平田　健司 (ヒラタ　ケンジ)

医学研究院　内科系部門　放射線科学分野准教授
北海道大学病院准教授
高等教育推進機構准教授
Last Updated :2025/06/10

■研究者基本情報

学位

  • 博士（医学）, 北海道大学, 2011年03月

プロフィール情報

  • 核医学を中心に、画像解析やディープ・ラーニングを利用した診断法、ヘルスケアに関する研究を行っています。ChatGPTなどの自然言語処理を生かした研究も行っています。コンピューターの高い計算能力をうまく利用し、人間は人間にしかできないことをするというのが目標です。

Researchmap個人ページ

ホームページURL

研究者番号

  • 30431365

J-Global ID

研究キーワード

  • 生成AI
  • 医療情報学
  • ChatGPT
  • 自然言語処理
  • RI内用療法
  • 人工知能
  • 放射線医学
  • コンピューター支援診断
  • 脳腫瘍
  • ポジトロン断層撮影法
  • FMISO
  • 低酸素
  • 核医学(PET,SPECT)
  • 画像診断学(含放射線診断学、核医学)
  • 分子イメージング

研究分野

  • ライフサイエンス, 腫瘍診断、治療学
  • ライフサイエンス, 放射線科学

担当教育組織

■経歴

経歴

  • 2020年04月 - 現在
    北海道大学病院, 核医学診療科, 診療科長, 日本国
  • 2020年04月 - 現在
    北海道大学大学院医学研究院, 画像診断学教室, 准教授
  • 2019年04月 - 2020年03月
    北海道大学大学院医学研究院, 画像診断学教室, 助教, 日本国
  • 2016年04月 - 2019年03月
    北海道大学大学院医学研究院, 核医学教室, 助教
  • 2014年11月 - 2016年03月
    北海道大学大学院医学研究科, 核医学分野, 特任助教, 日本国
  • 2012年11月 - 2014年10月
    カリフォルニア大学ロサンゼルス校, Department of Molecular and Medical Pharmacology, 博士研究員
  • 2012年04月 - 2012年10月
    北海道大学, 大学院医学研究科, 助教
  • 2006年04月 - 2012年03月
    北海道大学病院, 核医学診療科, 医員, 日本国

学歴

  • 2007年04月 - 2011年03月, 北海道大学, 大学院医学研究科, 日本国
  • 1996年04月 - 2002年03月, 北海道大学, 医学部, 医学科, 日本国
  • 1993年04月 - 1996年03月, 北海道岩見沢東高等学校, 日本国

委員歴

  • 2025年01月 - 現在
    日本医療情報学会, 評議員
  • 2024年04月 - 現在
    日本核医学会, ポジトロン核医学利用専門委員会, 学協会
  • 2024年 - 現在
    日本医学放射線学会, TOP GUN 第二期生
  • 2023年11月 - 現在
    日本核医学会, 評議員, 学協会
  • 2023年10月 - 現在
    European Journal of Nuclear Medicine and Molecular Imaging, Editorial Board, 学協会
  • 2023年07月 - 現在
    日本放射線科専門医会・医会, 人工知能診療委員会委員長
  • 2023年04月 - 現在
    日本メディカルAI学会, 評議員, 学協会
  • 2023年 - 現在
    日本医学放射線学会, 編集委員
  • 2022年 - 現在
    日本医学放射線学会, 放射線科業務量調査委員会
  • 2021年11月 - 現在
    北海道, 泊発電所環境保全監視協議会技術部会委員, 自治体
  • 2021年11月 - 現在
    日本核医学会, Annals of Nuclear Medicine編集委員, 学協会
  • 2021年11月 - 現在
    日本核医学会, PET撮像施設認証制度委員会委員, 学協会
  • 2021年11月 - 現在
    日本核医学会, 医療機器としての単体ソフトウェアの開発支援と診断指標の標準化に関する委員会, 学協会
  • 2021年07月 - 現在
    日本放射線科専門医会・医会, 理事, 学協会
  • 2020年06月 - 現在
    日本核医学会, 会員情報電子化推進作業部会委員, 学協会
  • 2017年10月 - 現在
    日本核医学会, 日中核医学交流運営委員, 学協会
  • 2015年09月 - 現在
    BMC Cancer, Associate Editor, 学協会
  • 2022年 - 2024年
    日本医学放射線学会, TOP GUN 第一期生
  • 2021年11月 - 2023年10月
    日本核医学会, 推薦評議員, 学協会
  • 2021年10月 - 2023年03月
    日本核医学会, 全国核医学診療実態調査専門委員
  • 2017年10月 - 2019年10月
    日本核医学会, 推薦評議員, 学協会
  • 2016年04月 - 2018年03月
    日本核医学会, 全国核医学診療実態調査専門委員, 学協会

■研究活動情報

受賞

  • 2025年04月, 日本医学放射線学会, JJR Promotion Award (Silver Medal)　　　　　　　　　　　　　　　
  • 2025年04月, 日本医学放射線学会, JJR Reviewer Award (Excellent Reviewer)　　　　　　　　　　　　　　　
  • 2023年09月, 北海道大学医学部, エクセレント・ティーチャー優秀賞　　　　　　　　　　　　　　　
  • 2022年07月, Japanese College of Radiology, Fellow of Japanese College of Radiology　　　　　　　　　　　　　　　
  • 2021年11月, 日本核医学会, 日本核医学会賞　　　　　　　　　　　　　　　
  • 2019年08月, 北海道大学医学部, エクセレント・ティーチャー優秀賞　　　　　　　　　　　　　　　
  • 2017年11月, 核医学画像解析研究会, 菅野賞　　　　　　　　　　　　　　　
  • 2016年05月, Asian School of Nuclear Medicine, Rising NM Professional Challenge, Gold Award　　　　　　　　　　　　　　　
  • 2016年04月, 日本医学放射線学会, 優秀論文賞　　　　　　　　　　　　　　　
  • 2015年11月, 日本核医学会, リターニー奨励賞　　　　　　　　　　　　　　　
  • 2015年04月, 日本医学放射線学会, CyPos賞Silver Medal　　　　　　　　　　　　　　　
  • 2013年11月, 日本核医学会, 研究奨励賞 最優秀賞　　　　　　　　　　　　　　　
  • 2013年06月, 米国核医学会, ポスター賞　　　　　　　　　　　　　　　
  • 2012年04月, 日本医学放射線学会, CyPos賞Gold Medal　　　　　　　　　　　　　　　

論文

  • Continual Self-supervised Learning Considering Medical Domain Knowledge in Chest CT Images
    Ren Tasai, Guang Li, Ren Togo, Minghui Tang, Takaaki Yoshimura, Hiroyuki Sugimori, Kenji Hirata, Takahiro Ogawa, Kohsuke Kudo, Miki Haseyama
    ICASSP 2025 - 2025 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 1, 5, IEEE, 2025年04月06日
    研究論文（国際会議プロシーディングス）
  • Factors and predictors affecting late external dose rates and isolation period in patients after lutetium-177-labeled DOTA-Tyr3-octreotate treatment for neuroendocrine tumors.
    Naoto Wakabayashi, Shiro Watanabe, Satoshi Takeuchi, Takahiro Tsuchikawa, Yamato Munakata, Kenji Hirata, Rina Kimura, Junki Takenaka, Hiroshi Ishii, Kohsuke Kudo
    Annals of nuclear medicine, 2025年04月05日, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: In peptide receptor radionuclide therapy (PRRT) using lutetium-177-labeled DOTA-Tyr3-octreotate ([177Lu] DOTATATE), isolation is required until the external dose rate at 1 m (EDR-1 m) from the body surface falls below the regulatory standards of each country. While it is known that renal function influences EDR-1 m reduction within 180 min post-administration, the factors affecting EDR-1 m on the day following administration (Late EDR-1 m) remain unclear. This study aimed to identify factors influencing Late EDR-1 m after PRRT using [177Lu] DOTATATE for neuroendocrine tumors and to predict Late EDR-1 m using pretreatment [111In] pentetreotide single-photon emission computed tomography/computed tomography (SPECT/CT) data. METHODS: This study analyzed 111 PRRT cycles administered to 36 patients between September 2021 and August 2024. Late EDR-1 m was set as the dependent variable, whereas total radiopharmaceutical uptake (LUTtotal), dose per body weight, creatinine clearance (CCr), and albumin-bilirubin (ALBI) score were set as the independent variables in the multiple regression analysis. LUTtotal was calculated using SPECT/CT data acquired after the patient left the radiation therapy room, defining the volume of interest (VOI) as the area with SUVmean + 2SD or higher in the skeletal muscle. The VOI volume multiplied by the SUVmean was used to define LUTtotal. In addition, using [111In] pentetreotide SPECT/CT data, the total radiopharmaceutical uptake (OCTtotal) was calculated in a manner similar to LUTtotal, and its correlation with LUTtotal was examined. A predictive equation for Late EDR-1 m was developed using the results of the multivariate analysis, and its performance was tested using subsequent cases between August 2024 and January 2025. RESULTS: The median measured Late EDR-1 m was 8.0 (range, 4.0-26.0) μSv/h. LUTtotal and dose per body weight were significantly correlated with Late EDR-1 m, whereas CCr and ALBI scores were not. Based on the results of the multivariate analysis, the predictive equation using the dose per body weight, assuming a dosage of 7400 MBq and OCTtotal, achieved a root mean square error (RMSE) of 2.24 μSv/h. In subsequent test cases, the RMSE was 3.47 μSv/h. CONCLUSIONS: Late EDR-1 m is significantly correlated with LUTtotal and dose per body weight. It can be accurately predicted using [111In] pentetreotide SPECT/CT data.
  • Artificial intelligence challenge of discriminating cutaneous arteritis and polyarteritis nodosa based on hematoxylin-and-eosin images of skin biopsy specimens
    Wataru Kashiwa, Kenji Hirata, Hiroki Endo, Kohsuke Kudo, Chietsugu Katoh, Tamihiro Kawakami, Hiroyuki Kanno, Kei Takahashi, Tatsuhiko Miyazaki, Eiji Ikeda, Toshiaki Oharaseki, Yayoi Ogawa, Mitsuho Onimaru, Mie Kurata, Daigo Nakazawa, Eri Muso, Yuka Nishibata, Sakiko Masuda, Utano Tomaru, Yoshihiro Matsuno, Shunsuke Furuta, Yoshiyuki Abe, Naoto Tamura, Masayoshi Harigai, Akihiro Ishizu
    Pathology - Research and Practice, 155915, 155915, Elsevier BV, 2025年03月
    研究論文（学術雑誌）
  • Recent topics in musculoskeletal imaging focused on clinical applications of AI: How should radiologists approach and use AI?
    Taiki Nozaki, Masahiro Hashimoto, Daiju Ueda, Shohei Fujita, Yasutaka Fushimi, Koji Kamagata, Yusuke Matsui, Rintaro Ito, Takahiro Tsuboyama, Fuminari Tatsugami, Noriyuki Fujima, Kenji Hirata, Masahiro Yanagawa, Akira Yamada, Tomoyuki Fujioka, Mariko Kawamura, Takeshi Nakaura, Shinji Naganawa
    La radiologia medica, Springer Science and Business Media LLC, 2025年02月24日, ［査読有り］, ［招待有り］
    英語, 研究論文（学術雑誌）
  • Urinary Dopamine Levels Can Predict the Avidity of Post-Therapy [131I]MIBG Scintigraphy in Unresectable or Metastatic Pheochromocytomas and Paragangliomas: A Preliminary Clinical Study
    Junki Takenaka, Shiro Watanabe, Takashige Abe, Satoshi Takeuchi, Kenji Hirata, Rina Kimura, Hiroshi Ishii, Naoto Wakabayashi, Mungunkhuyag Majigsuren, Kohsuke Kudo
    Pharmaceuticals, 18, 2, 165, 165, MDPI AG, 2025年01月26日
    研究論文（学術雑誌）, Background/Objectives: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that produce catecholamines. Unresectable or metastatic PPGLs are treated with [131I]metaiodobenzylguanidine (MIBG), but MIBG avidity is often heterogeneous. Identifying predictive factors for non-avid lesions on scintigraphy is clinically important. The primary objective of this study was to investigate the relationship between MIBG avidity and catecholamine secretion patterns in patients with unresectable or metastatic PPGLs. Methods: This retrospective study included 27 patients treated with [131I]MIBG for unresectable/metastatic PPGLs between 2001 and 2024. Patients received a single intravenous dose of [131I]MIBG (5.5–7.4 GBq), with post-therapy scintigraphy performed 3–7 days later. Non-avid lesions were assessed by imaging and confirmed using CT, MRI, and FDG-PET. Clinical factors, including age, sex, prior treatments, metastasis sites, and urine catecholamines, were evaluated using univariate logistic analysis. Predictive factors were assessed via receiver operating characteristic curves. Results: Non-avid lesions were found in nine patients (33.3%). These patients were younger (median age 38 vs. 62.5 years) and had higher urine dopamine levels (median 1510 vs. 779 μg/day) than those without non-avid lesions. Younger age (odds ratio: 0.892, p < 0.01) and higher urinary dopamine levels (odds ratio: 1.003, p < 0.01) were significantly associated with non-avid lesions. All patients > 45 years with urinary dopamine < 1190 μg/day had no non-avid lesions, whereas patients < 45 years with urinary dopamine > 1190 μg/day had non-avid lesions. Conclusions: Age and urinary dopamine levels may predict non-avid lesions in unresectable/metastatic PPGLs, aiding treatment decisions for [131I]MIBG therapy. This article is a revised and expanded version of a paper entitled “Urine dopamine level and age can predict non-avid lesion on scintigraphy after I-131 MIBG treatment for unresectable/metastatic PPGL”, which was presented at SNMMI 2024, Toronto, from 8 June to 11 June 2024.
  • Stereotactic arrhythmia radioablation for ventricular tachycardia: a review of clinical trials and emerging roles of imaging
    Mariko Kawamura, Masafumi Shimojo, Fuminari Tatsugami, Kenji Hirata, Shohei Fujita, Daiju Ueda, Yusuke Matsui, Yasutaka Fushimi, Tomoyuki Fujioka, Taiki Nozaki, Akira Yamada, Rintaro Ito, Noriyuki Fujima, Masahiro Yanagawa, Takeshi Nakaura, Takahiro Tsuboyama, Koji Kamagata, Shinji Naganawa
    Journal of Radiation Research, Oxford University Press (OUP), 2024年12月05日
    研究論文（学術雑誌）, ABSTRACT

    Ventricular tachycardia (VT) is a severe arrhythmia commonly treated with implantable cardioverter defibrillators, antiarrhythmic drugs and catheter ablation (CA). Although CA is effective in reducing recurrent VT, its impact on survival remains uncertain, especially in patients with extensive scarring. Stereotactic arrhythmia radioablation (STAR) has emerged as a novel treatment for VT in patients unresponsive to CA, leveraging techniques from stereotactic body radiation therapy used in cancer treatments. Recent clinical trials and case series have demonstrated the short-term efficacy and safety of STAR, although long-term outcomes remain unclear. Imaging techniques, such as electroanatomical mapping, contrast-enhanced magnetic resonance imaging and nuclear imaging, play a crucial role in treatment planning by identifying VT substrates and guiding target delineation. However, challenges persist owing to the complex anatomy and variability in target volume definitions. Advances in imaging and artificial intelligence are expected to improve the precision and efficacy of STAR. The exact mechanisms underlying the antiarrhythmic effects of STAR, including potential fibrosis and improvement in cardiac conduction, are still being explored. Despite its potential, STAR should be cautiously applied in prospective clinical trials, with a focus on optimizing dose delivery and understanding long-term outcomes. Collaborative efforts are necessary to standardize treatment strategies and enhance the quality of life for patients with refractory VT.
  • Advancing clinical MRI exams with artificial intelligence: Japan’s contributions and future prospects
    Shohei Fujita, Yasutaka Fushimi, Rintaro Ito, Yusuke Matsui, Fuminari Tatsugami, Tomoyuki Fujioka, Daiju Ueda, Noriyuki Fujima, Kenji Hirata, Takahiro Tsuboyama, Taiki Nozaki, Masahiro Yanagawa, Koji Kamagata, Mariko Kawamura, Akira Yamada, Takeshi Nakaura, Shinji Naganawa
    Japanese Journal of Radiology, Springer Science and Business Media LLC, 2024年11月16日
    研究論文（学術雑誌）, Abstract

    In this narrative review, we review the applications of artificial intelligence (AI) into clinical magnetic resonance imaging (MRI) exams, with a particular focus on Japan’s contributions to this field. In the first part of the review, we introduce the various applications of AI in optimizing different aspects of the MRI process, including scan protocols, patient preparation, image acquisition, image reconstruction, and postprocessing techniques. Additionally, we examine AI’s growing influence in clinical decision-making, particularly in areas such as segmentation, radiation therapy planning, and reporting assistance. By emphasizing studies conducted in Japan, we highlight the nation’s contributions to the advancement of AI in MRI. In the latter part of the review, we highlight the characteristics that make Japan a unique environment for the development and implementation of AI in MRI examinations. Japan’s healthcare landscape is distinguished by several key factors that collectively create a fertile ground for AI research and development. Notably, Japan boasts one of the highest densities of MRI scanners per capita globally, ensuring widespread access to the exam. Japan’s national health insurance system plays a pivotal role by providing MRI scans to all citizens irrespective of socioeconomic status, which facilitates the collection of inclusive and unbiased imaging data across a diverse population. Japan’s extensive health screening programs, coupled with collaborative research initiatives like the Japan Medical Imaging Database (J-MID), enable the aggregation and sharing of large, high-quality datasets. With its technological expertise and healthcare infrastructure, Japan is well-positioned to make meaningful contributions to the MRI–AI domain. The collaborative efforts of researchers, clinicians, and technology experts, including those in Japan, will continue to advance the future of AI in clinical MRI, potentially leading to improvements in patient care and healthcare efficiency.
  • Lung Cancer Classification Using Masked Autoencoder Pretrained on J-MID Database
    Ren Tasai, Guang Li, Ren Togo, Minghui Tang, Takaaki Yoshimura, Hiroyuki Sugimori, Kenji Hirata, Takahiro Ogawa, Kohsuke Kudo, Miki Haseyama
    2024 IEEE 13th Global Conference on Consumer Electronics (GCCE), 456, 457, IEEE, 2024年10月29日
    研究論文（国際会議プロシーディングス）
  • The Evolution and Clinical Impact of Deep Learning Technologies in Breast MRI.
    Tomoyuki Fujioka, Shohei Fujita, Daiju Ueda, Rintaro Ito, Mariko Kawamura, Yasutaka Fushimi, Takahiro Tsuboyama, Masahiro Yanagawa, Akira Yamada, Fuminari Tatsugami, Koji Kamagata, Taiki Nozaki, Yusuke Matsui, Noriyuki Fujima, Kenji Hirata, Takeshi Nakaura, Ukihide Tateishi, Shinji Naganawa
    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 2024年10月29日, ［国内誌］
    英語, 研究論文（学術雑誌）, The integration of deep learning (DL) in breast MRI has revolutionized the field of medical imaging, notably enhancing diagnostic accuracy and efficiency. This review discusses the substantial influence of DL technologies across various facets of breast MRI, including image reconstruction, classification, object detection, segmentation, and prediction of clinical outcomes such as response to neoadjuvant chemotherapy and recurrence of breast cancer. Utilizing sophisticated models such as convolutional neural networks, recurrent neural networks, and generative adversarial networks, DL has improved image quality and precision, enabling more accurate differentiation between benign and malignant lesions and providing deeper insights into disease behavior and treatment responses. DL's predictive capabilities for patient-specific outcomes also suggest potential for more personalized treatment strategies. The advancements in DL are pioneering a new era in breast cancer diagnostics, promising more personalized and effective healthcare solutions. Nonetheless, the integration of this technology into clinical practice faces challenges, necessitating further research, validation, and development of legal and ethical frameworks to fully leverage its potential.
  • Applications of artificial intelligence in interventional oncology: An up-to-date review of the literature
    Yusuke Matsui, Daiju Ueda, Shohei Fujita, Yasutaka Fushimi, Takahiro Tsuboyama, Koji Kamagata, Rintaro Ito, Masahiro Yanagawa, Akira Yamada, Mariko Kawamura, Takeshi Nakaura, Noriyuki Fujima, Taiki Nozaki, Fuminari Tatsugami, Tomoyuki Fujioka, Kenji Hirata, Shinji Naganawa
    Japanese Journal of Radiology, Springer Science and Business Media LLC, 2024年10月02日, ［査読有り］, ［招待有り］
    英語, 研究論文（学術雑誌）, Abstract

    Interventional oncology provides image-guided therapies, including transarterial tumor embolization and percutaneous tumor ablation, for malignant tumors in a minimally invasive manner. As in other medical fields, the application of artificial intelligence (AI) in interventional oncology has garnered significant attention. This narrative review describes the current state of AI applications in interventional oncology based on recent literature. A literature search revealed a rapid increase in the number of studies relevant to this topic recently. Investigators have attempted to use AI for various tasks, including automatic segmentation of organs, tumors, and treatment areas; treatment simulation; improvement of intraprocedural image quality; prediction of treatment outcomes; and detection of post-treatment recurrence. Among these, the AI-based prediction of treatment outcomes has been the most studied. Various deep and conventional machine learning algorithms have been proposed for these tasks. Radiomics has often been incorporated into prediction and detection models. Current literature suggests that AI is potentially useful in various aspects of interventional oncology, from treatment planning to post-treatment follow-up. However, most AI-based methods discussed in this review are still at the research stage, and few have been implemented in clinical practice. To achieve widespread adoption of AI technologies in interventional oncology procedures, further research on their reliability and clinical utility is necessary. Nevertheless, considering the rapid research progress in this field, various AI technologies will be integrated into interventional oncology practices in the near future.
  • Generative AI and large language models in nuclear medicine: current status and future prospects.
    Kenji Hirata, Yusuke Matsui, Akira Yamada, Tomoyuki Fujioka, Masahiro Yanagawa, Takeshi Nakaura, Rintaro Ito, Daiju Ueda, Shohei Fujita, Fuminari Tatsugami, Yasutaka Fushimi, Takahiro Tsuboyama, Koji Kamagata, Taiki Nozaki, Noriyuki Fujima, Mariko Kawamura, Shinji Naganawa
    Annals of nuclear medicine, 2024年09月25日, ［査読有り］, ［招待有り］, ［筆頭著者, 責任著者］, ［国内誌］
    英語, 研究論文（学術雑誌）, This review explores the potential applications of Large Language Models (LLMs) in nuclear medicine, especially nuclear medicine examinations such as PET and SPECT, reviewing recent advancements in both fields. Despite the rapid adoption of LLMs in various medical specialties, their integration into nuclear medicine has not yet been sufficiently explored. We first discuss the latest developments in nuclear medicine, including new radiopharmaceuticals, imaging techniques, and clinical applications. We then analyze how LLMs are being utilized in radiology, particularly in report generation, image interpretation, and medical education. We highlight the potential of LLMs to enhance nuclear medicine practices, such as improving report structuring, assisting in diagnosis, and facilitating research. However, challenges remain, including the need for improved reliability, explainability, and bias reduction in LLMs. The review also addresses the ethical considerations and potential limitations of AI in healthcare. In conclusion, LLMs have significant potential to transform existing frameworks in nuclear medicine, making it a critical area for future research and development.
  • Initial validation of the clinical significance of the NETest in Japanese gastroenteropancreatic neuroendocrine tumor patients.
    Hao Zhang, Takahiro Tsuchikawa, Satoshi Takeuchi, Kenji Hirata, Kimitaka Tanaka, Aya Matsui, Yoshitsugu Nakanishi, Toshimichi Asano, Takehiro Noji, Toru Nakamura, Shintaro Takeuchi, Masataka Wada, Satoshi Hirano
    Endocrine journal, 71, 9, 873, 880, 2024年09月02日, ［国内誌］
    英語, 研究論文（学術雑誌）, As novel biomarkers for gastroenteropancreatic neuroendocrine tumors (GEPNET) are in demand, we aimed to validate the clinical value of the NETest in Japanese patients. Between 2021 and 2023, blood and clinical data were collected from patients with GEPNET. Among 35 patients (median age: 59 [49-66] years), 27 cases originated from the pancreas and eight from the gastrointestinal tract. Of 69 samples sent to the laboratory, 56 (81.2%) underwent NETest. The diagnostic sensitivity was 97.1%. Among three patients who underwent R0 resection and four treated with peptide receptor radionuclide therapy, the changes in NETest scores closely correlated with disease progression. The NETest demonstrated high diagnostic efficacy and accurate therapeutic monitoring capabilities in a Japanese population.
  • Cardiovascular imaging in cardio-oncology
    Nagara Tamaki, Osamu Manabe, Kenji Hirata
    Japanese Journal of Radiology, Springer Science and Business Media LLC, 2024年08月29日, ［査読有り］, ［最終著者］
    英語, 研究論文（学術雑誌）, Abstract

    Advances in cancer treatment have improved in patient survival rate. On the other hand, management of cardiovascular complications has been increasingly required in cancer patients. Thus, cardio-oncology has attracted the attention by both oncologists and cardiologists. Cardiovascular imaging has played a key role for non-invasive assessment of cardiovascular alterations complimentary to biomarkers and clinical assessment. Suitable imaging selection and interpretation may allow early diagnosis of cardiovascular injury with potential implications for therapeutic management and improved outcomes after cancer therapy. Echocardiography has been commonly used to evaluate cardiac dysfunction in cardio-oncology area. Cardiac CT is valuable for assessing structural abnormalities of the myocardium, coronary arteries, and aorta. Molecular imaging has an important role in the assessment of the pathophysiology and future treatment strategy of cardiovascular dysfunction. Cardiac MRI is valuable for characterization of myocardial tissue. PET and SPECT molecular imaging has potential roles for quantitative assessment of cardiovascular disorders. Particularly, FDG-PET is considered as an elegant approach for simultaneous assessment of tumor response to cancer therapy and early detection of possible cardiovascular involvement as well. This review describes the promising potential of these non-invasive cardiovascular imaging modalities in cardio-oncology.
  • Recent trends in AI applications for pelvic MRI: a comprehensive review
    Takahiro Tsuboyama, Masahiro Yanagawa, Tomoyuki Fujioka, Shohei Fujita, Daiju Ueda, Rintaro Ito, Akira Yamada, Yasutaka Fushimi, Fuminari Tatsugami, Takeshi Nakaura, Taiki Nozaki, Koji Kamagata, Yusuke Matsui, Kenji Hirata, Noriyuki Fujima, Mariko Kawamura, Shinji Naganawa
    La radiologia medica, Springer Science and Business Media LLC, 2024年08月03日, ［査読有り］, ［招待有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Magnetic resonance imaging (MRI) is an essential tool for evaluating pelvic disorders affecting the prostate, bladder, uterus, ovaries, and/or rectum. Since the diagnostic pathway of pelvic MRI can involve various complex procedures depending on the affected organ, the Reporting and Data System (RADS) is used to standardize image acquisition and interpretation. Artificial intelligence (AI), which encompasses machine learning and deep learning algorithms, has been integrated into both pelvic MRI and the RADS, particularly for prostate MRI. This review outlines recent developments in the use of AI in various stages of the pelvic MRI diagnostic pathway, including image acquisition, image reconstruction, organ and lesion segmentation, lesion detection and classification, and risk stratification, with special emphasis on recent trends in multi-center studies, which can help to improve the generalizability of AI.
  • Interpretive Structure Modeling(ISM)による看護DX推進の阻害要因の分析および提案　　　　　　　　　　　　　　　
    杉村 直孝, 栗原 知己, 鵜飼 真千子, 大橋 和貴, 平田 健司, 小笠原 克彦
    日本医療情報学会看護学術大会論文集, 25回, 195, 196, 日本医療情報学会看護部会, 2024年08月
    日本語
  • The Effectiveness of Semi-Supervised Learning Techniques in Identifying Calcifications in X-ray Mammography and the Impact of Different Classification Probabilities
    Miu Sakaida, Takaaki Yoshimura, Minghui Tang, Shota Ichikawa, Hiroyuki Sugimori, Kenji Hirata, Kohsuke Kudo
    Applied Sciences, 14, 14, 5968, 5968, MDPI AG, 2024年07月09日, ［査読有り］
    研究論文（学術雑誌）, Identifying calcifications in mammograms is crucial for early breast cancer detection, and semi-supervised learning, which utilizes a small dataset for supervised learning combined with deep learning, is anticipated to be an effective approach for automating this identification process. This study explored the impact of semi-supervised learning on identifying mammographic calcifications by including 712 mammographic images from 252 patients in public datasets. Initially, 212 mammogram images were segmented into patches and classified visually for calcification presence. A subset of these patches, derived from 169 mammogram images, was used to train a ResNet50-based classifier. The classifier was evaluated using patches generated from 43 mammograms as a test data set. Additionally, 500 more mammogram images were processed into patches and analyzed using the trained ResNet50 model, with semi-supervised learning applied to patches exceeding certain classification probabilities. This process aimed to enhance the classifier’s accuracy and achieve improvements over the initial model. The findings indicated that semi-supervised learning significantly benefits the accuracy of calcification detection in mammography, underscoring its utility in enhancing diagnostic methodologies.
  • Safety and efficacy of multiple-dose versus single-dose MIBG therapy in patients with refractory pheochromocytoma and paraganglioma: a single-center retrospective analysis.
    Naoto Wakabayashi, Shiro Watanabe, Takashige Abe, Junki Takenaka, Kenji Hirata, Rina Kimura, Keita Sakamoto, Nobuo Shinohara, Kohsuke Kudo
    Annals of nuclear medicine, 38, 7, 553, 562, 2024年07月, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: To investigate the incidence of adverse events (AEs) following single and multiple administrations of I-131 metaiodobenzylguanidine (MIBG) therapy for inoperable pheochromocytomas and paragangliomas (PPGLs). METHODS: A single-center retrospective study was conducted on patients with inoperable PPGLs who underwent I-131 MIBG therapy between January 2000 and December 2020. A total of 28 patients with available electronic medical records were included. The treatment consisted of a single intravenous administration of 150 mCi (5.55 GBq) of I-131 MIBG. We evaluated the first MIBG treatment and repeated MIBG treatments performed within 200 days of the previous treatment. AEs for each treatment were evaluated using CTCAE version 4.0, and the statistical analysis was conducted at a significance level of p < 0.05. Objective response based on RECIST 1.1 criteria and biochemical response based on urinary catecholamines were assessed. RESULTS: The study included a total of 63 administrations, consisting of 28 single administrations (SAs), including the first administration for all 28 cases, and 35 multiple administrations (MAs), which included the second or later administrations. Hematological AEs were evaluable for 23 SAs and 29 MAs. Grade 3 or higher leukopenia occurred in 9.8% of all administrations, and Grade 3 or higher lymphopenia in 23.5%; both were manageable through observation. There were no significant differences in clinical AE Grades 1-2 (p = 0.32), hematological AE Grades 1-2 (p = 0.22), or hematological AE Grades 3-4 (p = 0.12) between MAs and SAs. Statistical analysis for each type of AE revealed significant increases in leukopenia (p < 0.01) and lymphopenia (p = 0.04). No significant difference in anemia, thrombocytopenia, or neutropenia was observed between MAs and SAs. There was no significant increase in the incidence rate of Grade 3 or higher hematological AEs for any of the parameters. The objective response rate was 0% for SAs and 36% for MAs. Biochemical response rates were 18% for SAs and 67% for MAs. CONCLUSION: In I-131 MIBG therapy for PPGLs, multiple administrations significantly increased only Grade 1 or 2 lymphopenia and leukopenia compared to single administration.
  • 福祉・医療の現場から ヘルスケア領域における教育用動画制作手法の検討 360度動画と3DCG動画の比較　　　　　　　　　　　　　　　
    コリー 紀代, 五十嵐 真里, 二宮 伸治, 平田 健司, 渡邊 祐介, 高橋 誠, 長 和俊, 中村 美鈴
    地域ケアリング, 26, 6, 62, 67, (株)北隆館, 2024年06月
    日本語
  • Climate change and artificial intelligence in healthcare: Review and recommendations towards a sustainable future
    Daiju Ueda, Shannon L Walston, Shohei Fujita, Yasutaka Fushimi, Takahiro Tsuboyama, Koji Kamagata, Akira Yamada, Masahiro Yanagawa, Rintaro Ito, Noriyuki Fujima, Mariko Kawamura, Takeshi Nakaura, Yusuke Matsui, Fuminari Tatsugami, Tomoyuki Fujioka, Taiki Nozaki, Kenji Hirata, Shinji Naganawa
    Diagnostic and Interventional Imaging, Elsevier BV, 2024年06月, ［査読有り］, ［招待有り］
    研究論文（学術雑誌）
  • 血液維持透析患者の甲状腺癌に対して放射性ヨウ素内用療法を施行した1例　　　　　　　　　　　　　　　
    江口 みな, 上田 雄翔, 中沢 大悟, 西尾 妙織, 竹中 淳規, 渡邊 史郎, 平田 健司, 村田 裕宣, 千葉 裕基, 武貞 敬介, 篠原 信雄
    日本透析医学会雑誌, 57, Suppl.1, 479, 479, (一社)日本透析医学会, 2024年05月
    日本語
  • Maximum standardized uptake value in 11C-methionine positron emission tomography may predict the prognosis of patients with oral squamous cell carcinoma
    Kuroshima T, Kitagawa Y, Sato J, Watanabe S, Asaka T, Abe T, Harada H, Hirata K, Kuge Y
    Odontologgy, PMID: 38703257, 2024年05月, ［査読有り］
  • 切除不能/転移性PPGLにおけるI-131 MIBG治療後シンチグラフィーで非集積病変を有する患者の予測因子に関する検討　　　　　　　　　　　　　　　
    竹中 淳規, 渡邊 史郎, 安部 崇重, 土川 貴裕, 竹内 啓, 平田 健司, 木村 理奈, 若林 直人, 篠原 信雄, 工藤 與亮
    日本内分泌外科学会雑誌, 41, Suppl.1, S202, S202, (一社)日本内分泌外科学会, 2024年04月
    日本語
  • Nuclear medicine practice in Japan: a report of the ninth nationwide survey in 2022.
    Atsutaka Okizaki, Yoshihiro Nishiyama, Yoshitaka Inui, Hideki Otsuka, Kentaro Takanami, Masatoyo Nakajo, Koya Nakatani, Munenobu Nogami, Kenji Hirata, Yukito Maeda, Mana Yoshimura, Hiroshi Wakabayashi
    Annals of nuclear medicine, 38, 4, 315, 327, 2024年04月, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, Subcommittee on Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to survey contemporary nuclear medicine practice and its changes over the years. The subcommittee sent questionnaires, including the number and category of examinations as well as the kind of the radiopharmaceuticals during the 30 days of June 2022 to all nuclear medicine institutes in Japan. The total numbers of them for the year 2022 were estimated depends on the 1-month data. A total of 1095 institutes responded to the survey, including 364 positron emission tomography (PET) centers. The recovery rate was 90.6%. The number of gamma cameras installed was 1299 in total, with 2.5% decrease in 5 years. Dual-head cameras and hybrid SPECT/CT scanners accounted for 83.8% and 35.5%, respectively. The number of single-photon tracer studies in 2022 was 1.11 million which means increase in 2.7% in 5 years. Bone scintigraphy was a leading examination (31.0%), followed by myocardial scintigraphy (27.1%) and cerebral perfusion study (23.8%) in order. The percentage of SPECT studies showed an increase from 63.5% in previous survey to 66.8% in this survey. PET centers have also increased from 389 to 412, as compared with the previous one. One hundred and twenty-two PET centers have installed one or two in-house cyclotrons. Increasing trends of the PET studies were observed from 1992 to 2017, the trend changed and PET studies showed 1.5% decrease in 5 years. 18F-FDG accounted for 98.6% (610,497 examinations). PET examinations using 11C-methionine, 13N-NH3 and 11C-PIB have decreased, with 1624, 2146 and 525 examinations, respectively in 2022. The total number of nuclear medicine examination was eventually increased by 1.0%. Therapies for pheochromocytoma or paraganglioma (PPGL) with 131I-MIBG and for neuroendocrine tumor with 177Lu-DOTA-TATE were newly started, however, a total number of targeted radionuclide therapy was decreased by 17.7% because 131I-radioiodine and 223Ra targeted therapies were decreased and supply of some radioisotopes was discontinued. 131I-radioiodine targeted therapy showed a decrease in 5 years (- 15.9%), including 4099 patients for thyroid cancer. The number of out-patient thyroid bed ablation therapy with 1110 MBq of 131I was also decreased to 1015 per year. The number of admission rooms specialized for radionuclide targeted therapy increased from 157 to 160. The number of 223Ra targeted therapies for castration-resistant metastatic prostate cancer (mCRPC) was 1041 patients. This survey was performed during COVID-19 pandemic, however, total number of nuclear medicine examinations was almost same as previous survey (+ 1.0%). Radionuclide therapies with 131I-MIBG and 177Lu-DOTA-TATE were newly started, and new radionuclide therapy will be available in future, therefore, the development of radionuclide therapy will be continued. We are convinced that this survey report is useful in understanding the current status of the nuclear medicine practice in Japan, and in devising the new strategy to strengthen a role of nuclear medicine.
  • The impact of large language models on radiology: a guide for radiologists on the latest innovations in AI.
    Takeshi Nakaura, Rintaro Ito, Daiju Ueda, Taiki Nozaki, Yasutaka Fushimi, Yusuke Matsui, Masahiro Yanagawa, Akira Yamada, Takahiro Tsuboyama, Noriyuki Fujima, Fuminari Tatsugami, Kenji Hirata, Shohei Fujita, Koji Kamagata, Tomoyuki Fujioka, Mariko Kawamura, Shinji Naganawa
    Japanese journal of radiology, 2024年03月29日, ［査読有り］, ［招待有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, The advent of Deep Learning (DL) has significantly propelled the field of diagnostic radiology forward by enhancing image analysis and interpretation. The introduction of the Transformer architecture, followed by the development of Large Language Models (LLMs), has further revolutionized this domain. LLMs now possess the potential to automate and refine the radiology workflow, extending from report generation to assistance in diagnostics and patient care. The integration of multimodal technology with LLMs could potentially leapfrog these applications to unprecedented levels.However, LLMs come with unresolved challenges such as information hallucinations and biases, which can affect clinical reliability. Despite these issues, the legislative and guideline frameworks have yet to catch up with technological advancements. Radiologists must acquire a thorough understanding of these technologies to leverage LLMs' potential to the fullest while maintaining medical safety and ethics. This review aims to aid in that endeavor.
  • Intracerebral transplantation of MRI-trackable autologous bone marrow stromal cells for patients with subacute ischemic stroke.
    Masahito Kawabori, Satoshi Kuroda, Hideo Shichinohe, Kaoru Kahata, Souichi Shiratori, Satoshi Ikeda, Taisuke Harada, Kenji Hirata, Khin Khin Tha, Masato Aragaki, Shunsuke Terasaka, Yoichi M Ito, Naoki Nishimoto, Shunsuke Ohnishi, Ichiro Yabe, Kohsuke Kudo, Kiyohiro Houkin, Miki Fujimura
    Med (New York, N.Y.), 2024年03月18日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Ischemic stroke is one of the leading causes of death and neurological disability worldwide, and stem cell therapy is highly expected to reverse the sequelae. This phase 1/2, first-in-human study evaluated the safety, feasibility, and monitoring of an intracerebral-transplanted magnetic resonance imaging (MRI)-trackable autologous bone marrow stromal cell (HUNS001-01) for patients with subacute ischemic stroke. METHODS: The study included adults with severe disability due to ischemic stroke. HUNS001-01 cultured with human platelet lysates and labeled with superparamagnetic iron oxide was stereotactically transplanted into the peri-infarct area 47-64 days after ischemic stroke onset (dose: 2 or 5 × 107 cells). Neurological and radiographic evaluations were performed throughout 1 year after cell transplantation. The trial was registered at UMIN Clinical Trial Registry (number UMIN000026130). FINDINGS: All seven patients who met the inclusion criteria successfully achieved cell expansion, underwent intracerebral transplantation, and completed 1 year of follow-up. No product-related adverse events were observed. The median National Institutes of Health Stroke Scale and modified Rankin scale scores before transplantation were 13 and 4, which showed improvements of 1-8 and 0-2, respectively. Cell tracking proved that the engrafted cells migrated toward the infarction border area 1-6 months after transplantation, and the quantitative susceptibility mapping revealed that cell signals at the migrated area constantly increased throughout the follow-up period up to 34% of that of the initial transplanted site. CONCLUSIONS: Intracerebral transplantation of HUNS001-01 was safe and well tolerated. Cell tracking shed light on the therapeutic mechanisms of intracerebral transplantation. FUNDING: This work was supported by the Japan Agency for Medical Research and Development (AMED; JP17bk0104045 and JP20bk0104011).
  • Improvement in the estimation of perfusable tissue fraction and myocardial flow reserve in the ischemic myocardial lesions using ECG-gated dynamic myocardial PET with 15O-water
    Ayaka Maruo, Keiichi Magota, Yamato Munakata, Kenji Hirata, Chietsugu Katoh
    Annals of Nuclear Medicine, Springer Science and Business Media LLC, 2024年03月13日, ［査読有り］
    研究論文（学術雑誌）
  • Prognostic Value of Combined Assessments of Late Gadolinium Enhancement and Fluorodeoxyglucose Uptake in Cardiac Sarcoidosis.
    Sho Kazui, Sakae Takenaka, Toshiyuki Nagai, Satonori Tsuneta, Kenji Hirata, Yoshiya Kato, Hirokazu Komoriyama, Yuta Kobayashi, Akinori Takahashi, Kiwamu Kamiya, Taro Temma, Takuma Sato, Atsushi Tada, Yutaro Yasui, Michikazu Nakai, Takahiro Sato, Ichizo Tsujino, Kohsuke Kudo, Satoshi Konno, Toshihisa Anzai
    JACC. Cardiovascular imaging, 2024年03月11日, ［査読有り］, ［国際誌］
    英語
  • Stability of standardized uptake values for quantitative bone SPECT for jawbone lesions: a single-center cross-sectional study.
    Hironobu Hata, Satoshi Shimomura, Kenji Imamachi, Jun Sato, Takuya Asaka, Kenji Hirata, Kyousuke Funayama, Yoichi Mori, Masashi Matsuzaka, Toshikazu Nambu, Yoshimasa Kitagawa
    BMC oral health, 24, 1, 305, 305, 2024年03月05日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: The long time required for bone uptake of radiopharmaceutical material after injection for bone scintigraphy is a burden for patients with poor health. Thus, to assess whether the uptake time could be reduced for single-photon emission computed tomography (SPECT) of the jawbone, this study evaluated differences in maximum standardized uptake values (SUVmax) within patients using SPECT imaging at 2 and 3 hours after radiopharmaceutical injection. METHODS: A total of 33 patients undergoing treatment or in post-treatment follow-up for medication-related osteonecrosis of the jaw, who visited our hospital between July 2020 and August 2021 and could receive SPECT twice on the same day, were enrolled in the study. Patients were injected with technetium-99 m hydroxymethylene diphosphonate (Tc-99 m HMDP) intravenously. The SUVmax for healthy parietal bones and jawbone lesions were calculated from the SPECT images using quantitative analysis software, and the SUVmax were compared between 2- and 3-hour uptake times. RESULTS: After exclusion, 30 patients were included in the study. In the 2-hour and 3-hour images, the median SUVmax of the parietal bones were 1.90 and 1.81, respectively, and those of the jawbone lesions were 9.25 and 9.39, respectively. The limits of agreement (LOA) ranged from - 0.33 to 0.25 in the parietal bones, and the %LOA ranged from - 9.8 to 17.3% in the jawbone lesions, showing high equivalence between the two uptake durations. The SUVmax showed no clinical differences between the 2- and 3-hour uptake durations for Tc-99 m HMDP SPECT of the jawbone. CONCLUSIONS: The results of this study justify a 2-3-hour uptake window when performing quantitative SPECT of the jawbone. Therefore, the minimum uptake time can potentially be reduced to only 2 hours.
  • 肺カルチノイド術後再発に対して放射性核種標識ペプチド療法を行った1例
    佐藤 祐麻, 榊原 純, 黒木 俊宏, 松野 吉宏, 平田 健司, 今野 哲
    日本呼吸器学会誌, 13, 2, 49, 53, (一社)日本呼吸器学会, 2024年03月
    日本語
  • MELASに類似した脳卒中様発作を生じた神経核内封入体病の1例　　　　　　　　　　　　　　　
    亀田 浩之, 原田 太以佑, 藤間 憲幸, 清水 幸衣, 池辺 洋平, 平田 健司, 矢部 一郎, 工藤 與亮
    北海道放射線医学雑誌, 4, 20, 24, (NPO)メディカルイメージラボ, 2024年03月
    日本語
  • Accumulation of Technetium-99m Tetrofosmin on Myocardial Perfusion Scintigraphy in a Patient With Immunoglobulin G4-Related Coronary Periarteritis
    Satonori Tsuneta, Kenichiro Suno, Yuichiro Fujieda, Masaya Watanabe, Shiro Watanabe, Kenji Hirata, Toshiyuki Nagai, Kohsuke Kudo
    Canadian Journal of Cardiology, 2024年03月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Sunburst appearanceを呈する頭蓋骨腫瘤を契機に発見された神経芽腫の1例　　　　　　　　　　　　　　　
    北川 悠, 竹中 淳規, 渡邊 史郎, 平田 健司, 内山 裕子, 木村 理奈, 中川 純一, 池辺 洋平, 工藤 與亮, 長谷河 昌孝, 澤井 彩織, 寺下 友佳代, 杉山 未奈子, 平林 真介, 長 祐子, 真部 淳
    Japanese Journal of Radiology, 42, Suppl., 5, 5, (公社)日本医学放射線学会, 2024年02月
    日本語
  • Diagnosis of skull-base invasion by nasopharyngeal tumors on CT with a deep-learning approach.
    Junichi Nakagawa, Noriyuki Fujima, Kenji Hirata, Taisuke Harada, Naoto Wakabayashi, Yuki Takano, Akihiro Homma, Satoshi Kano, Kazuyuki Minowa, Kohsuke Kudo
    Japanese journal of radiology, 2024年01月27日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, PURPOSE: To develop a convolutional neural network (CNN) model to diagnose skull-base invasion by nasopharyngeal malignancies in CT images and evaluate the model's diagnostic performance. MATERIALS AND METHODS: We divided 100 malignant nasopharyngeal tumor lesions into a training (n = 70) and a test (n = 30) dataset. Two head/neck radiologists reviewed CT and MRI images and determined the positive/negative skull-base invasion status of each case (training dataset: 29 invasion-positive and 41 invasion-negative; test dataset: 13 invasion-positive and 17 invasion-negative). Preprocessing involved extracting continuous slices of the nasopharynx and clivus. The preprocessed training dataset was used for transfer learning with Residual Neural Networks 50 to create a diagnostic CNN model, which was then tested on the preprocessed test dataset to determine the invasion status and model performance. Original CT images from the test dataset were reviewed by a radiologist with extensive head/neck imaging experience (senior reader: SR) and another less-experienced radiologist (junior reader: JR). Gradient-weighted class activation maps (Grad-CAMs) were created to visualize the explainability of the invasion status classification. RESULTS: The CNN model's diagnostic accuracy was 0.973, significantly higher than those of the two radiologists (SR: 0.838; JR: 0.595). Receiver operating characteristic curve analysis gave an area under the curve of 0.953 for the CNN model (versus 0.832 and 0.617 for SR and JR; both p < 0.05). The Grad-CAMs suggested that the invasion-negative cases were present predominantly in bone marrow, while the invasion-positive cases exhibited osteosclerosis and nasopharyngeal masses. CONCLUSIONS: This CNN technique would be useful for CT-based diagnosis of skull-base invasion by nasopharyngeal malignancies.
  • 神経内分泌腫瘍に対するLu-177 DOTATATE治療における投与翌日の体外線量率に影響を与える因子に関する検討　　　　　　　　　　　　　　　
    若林 直人, 渡邊 史郎, 竹内 啓, 土川 貴裕, 平田 健司, 木村 理奈, 竹中 淳規, 石井 宙史, 南部 敏和, 工藤 與亮
    核医学, 61, Suppl., S157, S157, (一社)日本核医学会, 2024年
    日本語
  • 切除不能/転移性PPGLにおけるMIBG治療前のFDG-PETの集積性に関する検討　　　　　　　　　　　　　　　
    竹中 淳規, 渡邊 史郎, 安部 崇重, 土川 貴裕, 竹内 啓, 平田 健司, 木村 理奈, 石井 宙史, 若林 直人, 工藤 與亮
    核医学, 61, Suppl., S169, S169, (一社)日本核医学会, 2024年
    日本語
  • 再発・転移を有する分化型甲状腺癌におけるソマトスタチンレセプター発現に関する検討　　　　　　　　　　　　　　　
    渡邊 史郎, 平田 健司, 竹中 淳規, 石井 宙史, 若林 直人, 宗像 大和, 孫田 惠一, 工藤 與亮
    核医学, 61, Suppl., S176, S176, (一社)日本核医学会, 2024年
    日本語
  • SurfaceMIP:FDG-PETで皮膚を観察するためのアルゴリズムの実装とパラメーター最適化　　　　　　　　　　　　　　　
    平田 健司, 木村 理奈, 唐 明輝, 渡邊 史郎, 竹中 淳規, 石井 宙史, 杉森 博行, 吉村 高明, 工藤 與亮
    核医学, 61, Suppl., S162, S162, (一社)日本核医学会, 2024年
    日本語
  • 2.5次元DDSRCNNを用いた低カウントPET画像の画質改善モデルの開発と定量性評価　　　　　　　　　　　　　　　
    遠藤 大輝, 吉村 高明, 唐 明輝, 杉森 博行, 孫田 惠一, 木村 理奈, 渡邊 史郎, 平田 健司, 工藤 與亮
    核医学, 61, Suppl., S188, S188, (一社)日本核医学会, 2024年
    日本語
  • Identifying G6PC3 as a Potential Key Molecule in Hypoxic Glucose Metabolism of Glioblastoma Derived from the Depiction of 18F-Fluoromisonidazole and 18F-Fluorodeoxyglucose Positron Emission Tomography.
    Michinari Okamoto, Shigeru Yamaguchi, Ryosuke Sawaya, Sumire Echizenya, Yukitomo Ishi, Sadahiro Kaneko, Hiroaki Motegi, Takuya Toyonaga, Kenji Hirata, Miki Fujimura
    BioMed research international, 2024, 2973407, 2973407, 2024年, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: Glioblastoma is the most aggressive primary brain tumor, characterized by its distinctive intratumoral hypoxia. Sequential preoperative examinations using fluorine-18-fluoromisonidazole (18F-FMISO) and fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) could depict the degree of glucose metabolism with hypoxic condition. However, molecular mechanism of glucose metabolism under hypoxia in glioblastoma has been unclear. The aim of this study was to identify the key molecules of hypoxic glucose metabolism. METHODS: Using surgically obtained specimens, gene expressions associated with glucose metabolism were analyzed in patients with glioblastoma (n = 33) who underwent preoperative 18F-FMISO and 18F-FDG PET to identify affected molecules according to hypoxic condition. Tumor in vivo metabolic activities were semiquantitatively evaluated by lesion-normal tissue ratio (LNR). Protein expression was confirmed by immunofluorescence staining. To evaluate prognostic value, relationship between gene expression and overall survival was explored in another independent nonoverlapping clinical cohort (n = 17) and validated by The Cancer Genome Atlas (TCGA) database (n = 167). RESULTS: Among the genes involving glucose metabolic pathway, mRNA expression of glucose-6-phosphatase 3 (G6PC3) correlated with 18F-FDG LNR (P = 0.03). In addition, G6PC3 mRNA expression in 18F-FMISO high-accumulated glioblastomas was significantly higher than that in 18F-FMISO low-accumulated glioblastomas (P < 0.01). Protein expression of G6PC3 was consistent with mRNA expression, which was confirmed by immunofluorescence analysis. These findings indicated that the G6PC3 expression might be facilitated by hypoxic condition in glioblastomas. Next, we investigated the clinical relevance of G6PC3 in terms of prognosis. Among the glioblastoma patients who received gross total resection, mRNA expressions of G6PC3 in the patients with poor prognosis (less than 1-year survival) were significantly higher than that in the patients who survive more than 3 years. Moreover, high mRNA expression of G6PC3 was associated with poor overall survival in glioblastoma, as validated by TCGA database. CONCLUSION: G6PC3 was affluently expressed in glioblastoma tissues with coincidentally high 18F-FDG and 18F-FMISO accumulation. Further, it might work as a prognostic biomarker of glioblastoma. Therefore, G6PC3 is a potential key molecule of glucose metabolism under hypoxia in glioblastoma.
  • Machine Learning-based Gait Analysis to Predict Clinical Frailty Scale in Elderly Patients with Heart Failure
    Yoshifumi Mizuguchi, Motoki Nakao, Toshiyuki Nagai, Yuki Takahashi, Takahiro Abe, Shigeo Kakinoki, Shogo Imagawa, Kenichi Matsutani, Takahiko Saito, Masashige Takahashi, Yoshiya Kato, Hirokazu Komoriyama, Hikaru Hagiwara, Kenji Hirata, Takahiro Ogawa, Takuto Shimizu, Manabu Otsu, Kunihiro Chiyo, Toshihisa Anzai
    European Heart Journal - Digital Health, Oxford University Press (OUP), 2023年12月20日, ［査読有り］
    研究論文（学術雑誌）, Abstract

    Aims

    Although frailty assessment is recommended for guiding treatment strategies and outcome prediction in elderly patients with heart failure (HF), most frailty scales are subjective and the scores vary among raters. We sought to develop a machine learning-based automatic rating method/system/model of the clinical frailty scale (CFS) for patients with HF.

    Methods and Results

    We prospectively examined 417 elderly (≥75 years) with symptomatic chronic HF patients from seven centers between January 2019 and October 2023. The patients were divided into derivation (n = 194) and validation (n = 223) cohorts. We obtained body-tracking motion data using a deep learning-based pose estimation library, on a smartphone camera. Predicted CFS was calculated from 128 key features, including gait parameters, using the Light Gradient Boosting Machine (LightGBM) model. To evaluate the performance of this model, we calculated Cohen’s weighted kappa (CWK) and intraclass correlation coefficient (ICC) between the predicted and actual CFSs. In the derivation and validation datasets, the LightGBM models showed excellent agreements between the actual and predicted CFSs (CWK 0.866, 95% CI 0.807-0.911; ICC 0.866, 95% CI 0.827-0.898; CWK 0.812, 95% CI 0.752-0.868; ICC 0.813, 95% CI 0.761-0.854, respectively). During a median follow-up period of 391 (IQR 273-617) days, the higher predicted CFS was independently associated with a higher risk of all-cause death (HR 1.60, 95% CI 1.02-2.50) after adjusting for significant prognostic covariates.

    Conclusion

    Machine learning-based algorithms of automatically CFS rating are feasible, and the predicted CFS is associated with the risk of all-cause death in elderly patients with HF.
  • Revolutionizing radiation therapy: the role of AI in clinical practice
    Mariko Kawamura, Takeshi Kamomae, Masahiro Yanagawa, Koji Kamagata, Shohei Fujita, Daiju Ueda, Yusuke Matsui, Yasutaka Fushimi, Tomoyuki Fujioka, Taiki Nozaki, Akira Yamada, Kenji Hirata, Rintaro Ito, Noriyuki Fujima, Fuminari Tatsugami, Takeshi Nakaura, Takahiro Tsuboyama, Shinji Naganawa
    Journal of Radiation Research, Oxford University Press (OUP), 2023年11月22日, ［査読有り］, ［招待有り］
    研究論文（学術雑誌）, Abstract

    This review provides an overview of the application of artificial intelligence (AI) in radiation therapy (RT) from a radiation oncologist’s perspective. Over the years, advances in diagnostic imaging have significantly improved the efficiency and effectiveness of radiotherapy. The introduction of AI has further optimized the segmentation of tumors and organs at risk, thereby saving considerable time for radiation oncologists. AI has also been utilized in treatment planning and optimization, reducing the planning time from several days to minutes or even seconds. Knowledge-based treatment planning and deep learning techniques have been employed to produce treatment plans comparable to those generated by humans. Additionally, AI has potential applications in quality control and assurance of treatment plans, optimization of image-guided RT and monitoring of mobile tumors during treatment. Prognostic evaluation and prediction using AI have been increasingly explored, with radiomics being a prominent area of research. The future of AI in radiation oncology offers the potential to establish treatment standardization by minimizing inter-observer differences in segmentation and improving dose adequacy evaluation. RT standardization through AI may have global implications, providing world-standard treatment even in resource-limited settings. However, there are challenges in accumulating big data, including patient background information and correlating treatment plans with disease outcomes. Although challenges remain, ongoing research and the integration of AI technology hold promise for further advancements in radiation oncology.
  • Comparative study of physiological FDG uptake in small structures between silicon photomultiplier-based PET and conventional PET.
    Shiro Watanabe, Kenji Hirata, Keiichi Magota, Junki Takenaka, Naoto Wakabayashi, Daiki Shinyama, Koichi Yasuda, Akihiro Homma, Kohsuke Kudo
    Annals of nuclear medicine, 2023年11月09日, ［査読有り］, ［責任著者］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: Silicon photomultiplier-based positron emission tomography/computed tomography (SiPM-PET/CT) has the superior spatial resolution to conventional PET/CT (cPET/CT). This head-to-head comparison study compared the images of physiological 18F-fluorodeoxyglucose (FDG) accumulation in small-volume structures between SiPM-PET/CT and cPET/CT in patients scanned with both modalities, and we investigated whether the thresholds that are reported to be useful for differentiating physiological accumulations from malignant lesions can also be applied to SiPM-PET/CT. METHODS: We enrolled 21 consecutive patients with head and neck malignancies who underwent whole-body FDG-PET/CT for initial staging or a follow-up evaluation (October 2020 to March 2022). After being injected with FDG, all patients underwent PET acquisition on both Vereos PET-CT and Gemini TF64 PET-CT systems (both Philips Healthcare) in random order. For each patient, the maximum standardized uptake value (SUVmax) was measured in the pituitary gland, esophagogastric junction (EGJ), adrenal glands, lumbar enlargement of the spinal cord, and epididymis. We measured the liver SUVmean and the blood pool SUVmean to calculate the target-to-liver ratio (TLR) and the target-to-blood ratio (TBR), respectively. Between-groups differences in each variable were examined by a paired t-test. We also investigated whether there were cases of target uptake greater than the reported threshold for distinguishing pathological from physiological accumulations. RESULTS: Data were available for 19 patients. Ten patients were in Group 1, i.e., the patients who underwent SiPM-PET first, and the remaining nine patients who underwent cPET first were in Group 2. In the SiPM-PET results, the SUVmax of all targets was significantly higher than that obtained by cPET in all patients, and this tendency was also observed when the patients were divided into Groups 1/2. The TLRs of all targets were significantly higher in SiPM-PET than in cPET in all patients, and SiPM-PET also showed significantly higher TBRs for all targets except the EGJ (p = 0.052). CONCLUSIONS: The physiological uptake in the small structures studied herein showed high accumulation on SiPM-PET. Our results also suggest that the thresholds reported for cPET to distinguish pathological accumulations likely lead to false-positive findings in SIPM-PET evaluations.
  • 労災疾病等医学研究令和5年度開始「じん肺」テーマについて　　　　　　　　　　　　　　　
    大塚 義紀, 平田 健司, 唐 明輝, 中川 純一, 宇佐美 郁治, 岸本 卓巳, 水橋 啓一, 飯塚 幹也, 五十嵐 毅, 横山 多佳子, 木村 清延
    日本職業・災害医学会会誌, 71, 臨増, 別96, 別96, (一社)日本職業・災害医学会, 2023年11月
    日本語
  • 腫瘍性骨軟化症における111Inペンテトレオチドを用いたソマトスタチン受容体シンチグラフィにてSPECT-CTが有用であった一例　　　　　　　　　　　　　　　
    平野 佑亮, 平田 健司, 渡邊 史郎, 竹中 淳規, 孫田 惠一, 宗像 大和, 前田 佑介
    北海道放射線技術雑誌, 95, 39, 39, (公社)日本放射線技術学会-北海道支部, 2023年11月
    日本語, 研究論文（学術雑誌）
  • 労災疾病等医学研究令和5年度開始「じん肺」テーマについて　　　　　　　　　　　　　　　
    大塚 義紀, 平田 健司, 唐 明輝, 中川 純一, 宇佐美 郁治, 岸本 卓巳, 水橋 啓一, 飯塚 幹也, 五十嵐 毅, 横山 多佳子, 木村 清延
    日本職業・災害医学会会誌, 71, 臨増, 別96, 別96, (一社)日本職業・災害医学会, 2023年11月
    日本語, 研究論文（研究会，シンポジウム資料等）
  • Bone Echinococcosis Mimicking Malignancy on FDG PET.
    Junki Takenaka, Kenji Hirata, Shiro Watanabe, Masahiko Takahata, Kohsuke Kudo
    Clinical nuclear medicine, 48, 11, e523-e525, 2023年11月01日, ［査読有り］, ［責任著者］, ［国際誌］
    英語, 研究論文（学術雑誌）, MRI revealed a thoracic vertebrae lesion in a 40-year-old woman with back pain. She was referred to our institution; MRI demonstrated a mass from the second to the fifth thoracic vertebra and compression fractures. CT revealed a splenic mass, multiple pulmonary nodules, and low-density masses in the liver. 18 F-FDG PET/CT showed increased uptake (SUV max , 10.6) in the peripheral rim of the thoracic vertebra mass, with central parts showing lower uptake than the peripheral rim. The splenic mass exhibited increased accumulation (SUV max , 4.8). The thoracic spine lesion was fixed; a biopsy was performed. Alveolar echinococcosis was confirmed immunologically. Alveolar echinococcosis can present with bone lesions. It must be differentiated from malignancy.
  • Convolutional neural network-based program to predict lymph node metastasis of non-small cell lung cancer using 18F-FDG PET.
    Eitaro Kidera, Sho Koyasu, Kenji Hirata, Masatsugu Hamaji, Ryusuke Nakamoto, Yuji Nakamoto
    Annals of nuclear medicine, 2023年09月27日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, PURPOSE: To develop a convolutional neural network (CNN)-based program to analyze maximum intensity projection (MIP) images of 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron emission tomography (PET) scans, aimed at predicting lymph node metastasis of non-small cell lung cancer (NSCLC), and to evaluate its effectiveness in providing diagnostic assistance to radiologists. METHODS: We obtained PET images of NSCLC from public datasets, including those of 435 patients with available N-stage information, which were divided into a training set (n = 304) and a test set (n = 131). We generated 36 maximum intensity projection (MIP) images for each patient. A residual network (ResNet-50)-based CNN was trained using the MIP images of the training set to predict lymph node metastasis. Lymph node metastasis in the test set was predicted by the trained CNN as well as by seven radiologists twice: first without and second with CNN assistance. Diagnostic performance metrics, including accuracy and prediction error (the difference between the truth and the predictions), were calculated, and reading times were recorded. RESULTS: In the test set, 67 (51%) patients exhibited lymph node metastases and the CNN yielded 0.748 predictive accuracy. With the assistance of the CNN, the prediction error was significantly reduced for six of the seven radiologists although the accuracy did not change significantly. The prediction time was significantly reduced for five of the seven radiologists with the median reduction ratio 38.0%. CONCLUSION: The CNN-based program could potentially assist radiologists in predicting lymph node metastasis by increasing diagnostic confidence and reducing reading time without affecting diagnostic accuracy, at least in the limited situations using MIP images.
  • From FDG and beyond: the evolving potential of nuclear medicine.
    Kenji Hirata, Koji Kamagata, Daiju Ueda, Masahiro Yanagawa, Mariko Kawamura, Takeshi Nakaura, Rintaro Ito, Fuminari Tatsugami, Yusuke Matsui, Akira Yamada, Yasutaka Fushimi, Taiki Nozaki, Shohei Fujita, Tomoyuki Fujioka, Takahiro Tsuboyama, Noriyuki Fujima, Shinji Naganawa
    Annals of nuclear medicine, 2023年09月25日, ［査読有り］, ［招待有り］, ［筆頭著者, 責任著者］, ［国内誌］
    英語, 研究論文（学術雑誌）, The radiopharmaceutical 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) has been dominantly used in positron emission tomography (PET) scans for over 20 years, and due to its vast utility its applications have expanded and are continuing to expand into oncology, neurology, cardiology, and infectious/inflammatory diseases. More recently, the addition of artificial intelligence (AI) has enhanced nuclear medicine diagnosis and imaging with FDG-PET, and new radiopharmaceuticals such as prostate-specific membrane antigen (PSMA) and fibroblast activation protein inhibitor (FAPI) have emerged. Nuclear medicine therapy using agents such as [177Lu]-dotatate surpasses conventional treatments in terms of efficacy and side effects. This article reviews recently established evidence of FDG and non-FDG drugs and anticipates the future trajectory of nuclear medicine.
  • Predictive factors of early FDG-PET response to [131I] MIBG treatment for unresectable or metastatic pheochromocytomas and paragangliomas (PPGLs).
    Junki Takenaka, Shiro Watanabe, Takashige Abe, Takahiro Tsuchikawa, Satoshi Takeuchi, Kenji Hirata, Rina Kimura, Naoto Wakabayashi, Nobuo Shinohara, Kohsuke Kudo
    Neuroendocrinology, 2023年09月19日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours that produce catecholamines. [131I] MIBG-avid unresectable or metastatic PPGLs are treated with [131I] MIBG therapy. A high metabolic tumour volume (MTV) and total lesion glycolysis (TLG) can be poor prognostic factors. Therefore, we evaluated the metabolic responses to [131I] MIBG therapy with respect to other clinical factors.A retrospective study was performed on a series of 20 patients who underwent FDG-PET before and after [131I] MIBG therapy. We administered a single dose comprising 5.5 GBq of [131I] MIBG. Semi-quantitative parameters (SUVmax, MTV, and TLG) were calculated using the liver SUV (mean + 3SD) as a threshold on Metavol software. The semi-quantitative FDG-PET parameters for determining response were complete response , partial remission, stable disease, and progressive disease (PD). We divided our study participants into the PD and non-PD groups and compared the overall survival between the two groups. Subsequently, we evaluated the relationships between metabolic response and age, sex, tumour type, metastatic site, chemotherapy or external radiation history, and 24-hour urine catecholamine levels by univariate logistic regression analyses. Both MTV-based and TLG-based criteria for PD vs. non-PD were significant prognostic factors (p = 0.014). However, treatment response as evaluated based on the SUVmax was not a significant predictor. Higher urinary dopamine levels were associated with poor metabolic response as assessed by MTV and TLG. The other clinical parameters were non-significant. Poor metabolic response (measured with MTV and TLG) to [131I] MIBG therapy in unresectable or metastatic PPGLs was related to shorter OS. The poor metabolic response can be predicted using the urinary dopamine level.
  • New trend in artificial intelligence-based assistive technology for thoracic imaging.
    Masahiro Yanagawa, Rintaro Ito, Taiki Nozaki, Tomoyuki Fujioka, Akira Yamada, Shohei Fujita, Koji Kamagata, Yasutaka Fushimi, Takahiro Tsuboyama, Yusuke Matsui, Fuminari Tatsugami, Mariko Kawamura, Daiju Ueda, Noriyuki Fujima, Takeshi Nakaura, Kenji Hirata, Shinji Naganawa
    La Radiologia medica, 128, 10, 1236, 1249, 2023年08月28日, ［査読有り］, ［招待有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Although there is no solid agreement for artificial intelligence (AI), it refers to a computer system with intelligence similar to that of humans. Deep learning appeared in 2006, and more than 10 years have passed since the third AI boom was triggered by improvements in computing power, algorithm development, and the use of big data. In recent years, the application and development of AI technology in the medical field have intensified internationally. There is no doubt that AI will be used in clinical practice to assist in diagnostic imaging in the future. In qualitative diagnosis, it is desirable to develop an explainable AI that at least represents the basis of the diagnostic process. However, it must be kept in mind that AI is a physician-assistant system, and the final decision should be made by the physician while understanding the limitations of AI. The aim of this article is to review the application of AI technology in diagnostic imaging from PubMed database while particularly focusing on diagnostic imaging in thorax such as lesion detection and qualitative diagnosis in order to help radiologists and clinicians to become more familiar with AI in thorax.
  • Fairness of artificial intelligence in healthcare: review and recommendations.
    Daiju Ueda, Taichi Kakinuma, Shohei Fujita, Koji Kamagata, Yasutaka Fushimi, Rintaro Ito, Yusuke Matsui, Taiki Nozaki, Takeshi Nakaura, Noriyuki Fujima, Fuminari Tatsugami, Masahiro Yanagawa, Kenji Hirata, Akira Yamada, Takahiro Tsuboyama, Mariko Kawamura, Tomoyuki Fujioka, Shinji Naganawa
    Japanese journal of radiology, 2023年08月04日, ［査読有り］, ［招待有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, In this review, we address the issue of fairness in the clinical integration of artificial intelligence (AI) in the medical field. As the clinical adoption of deep learning algorithms, a subfield of AI, progresses, concerns have arisen regarding the impact of AI biases and discrimination on patient health. This review aims to provide a comprehensive overview of concerns associated with AI fairness; discuss strategies to mitigate AI biases; and emphasize the need for cooperation among physicians, AI researchers, AI developers, policymakers, and patients to ensure equitable AI integration. First, we define and introduce the concept of fairness in AI applications in healthcare and radiology, emphasizing the benefits and challenges of incorporating AI into clinical practice. Next, we delve into concerns regarding fairness in healthcare, addressing the various causes of biases in AI and potential concerns such as misdiagnosis, unequal access to treatment, and ethical considerations. We then outline strategies for addressing fairness, such as the importance of diverse and representative data and algorithm audits. Additionally, we discuss ethical and legal considerations such as data privacy, responsibility, accountability, transparency, and explainability in AI. Finally, we present the Fairness of Artificial Intelligence Recommendations in healthcare (FAIR) statement to offer best practices. Through these efforts, we aim to provide a foundation for discussing the responsible and equitable implementation and deployment of AI in healthcare.
  • Current State of Artificial Intelligence in Clinical Applications for Head and Neck MR Imaging.
    Noriyuki Fujima, Koji Kamagata, Daiju Ueda, Shohei Fujita, Yasutaka Fushimi, Masahiro Yanagawa, Rintaro Ito, Takahiro Tsuboyama, Mariko Kawamura, Takeshi Nakaura, Akira Yamada, Taiki Nozaki, Tomoyuki Fujioka, Yusuke Matsui, Kenji Hirata, Fuminari Tatsugami, Shinji Naganawa
    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 22, 4, 401, 414, 2023年08月01日, ［査読有り］, ［招待有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, Due primarily to the excellent soft tissue contrast depictions provided by MRI, the widespread application of head and neck MRI in clinical practice serves to assess various diseases. Artificial intelligence (AI)-based methodologies, particularly deep learning analyses using convolutional neural networks, have recently gained global recognition and have been extensively investigated in clinical research for their applicability across a range of categories within medical imaging, including head and neck MRI. Analytical approaches using AI have shown potential for addressing the clinical limitations associated with head and neck MRI. In this review, we focus primarily on the technical advancements in deep-learning-based methodologies and their clinical utility within the field of head and neck MRI, encompassing aspects such as image acquisition and reconstruction, lesion segmentation, disease classification and diagnosis, and prognostic prediction for patients presenting with head and neck diseases. We then discuss the limitations of current deep-learning-based approaches and offer insights regarding future challenges in this field.
  • Early prediction of treatment outcome for lenvatinib using 18F-FDG PET/CT in patients with unresectable or advanced thyroid carcinoma refractory to radioiodine treatment: a prospective, multicentre, non-randomised study.
    Satoshi Takeuchi, Kenji Hirata, Keiichi Magota, Shiro Watanabe, Rika Moku, Akihiko Shiiya, Jun Taguchi, Shin Ariga, Tomohiro Goda, Yoshihito Ohhara, Takurou Noguchi, Yasushi Shimizu, Ichiro Kinoshita, Rio Honma, Yasushi Tsuji, Akihiro Homma, Hirotoshi Dosaka-Akita
    EJNMMI research, 13, 1, 69, 69, 2023年07月17日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Lenvatinib is widely used to treat unresectable and advanced thyroid carcinomas. We aimed to determine whether 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) performed 1 week after lenvatinib treatment initiation could predict treatment outcomes. RESULTS: This was a prospective, nonrandomised, multicentre study. Patients with pathologically confirmed differentiated thyroid carcinoma (DTC) and lesions refractory to radioiodine treatment were eligible for inclusion. Patients were treated with 24 mg lenvatinib as the initial dose and underwent PET/CT examination 1 week after treatment initiation. Contrast-enhanced CT was scheduled at least 4 weeks later as the gold standard for evaluation. The primary endpoint was to evaluate the discrimination power of maximum standardised uptake value (SUVmax) obtained by PET/CT compared to that obtained by contrast-enhanced CT. Evaluation was performed using the area under the receiver operating characteristic (ROC-AUC) curve. Twenty-one patients were included in this analysis. Receiver operating characteristic (ROC) curve analysis yielded an AUC of 0.714 for SUVmax after 1 week of lenvatinib treatment. The best cut-off value for the treatment response for SUVmax was 15.211. The sensitivity and specificity of this cut-off value were 0.583 and 0.857, respectively. The median progression-free survival was 26.3 months in patients with an under-cut-off value and 19.7 months in patients with an over-cut-off value (P = 0.078). CONCLUSIONS: The therapeutic effects of lenvatinib were detected earlier than those of CT because of decreased FDG uptake on PET/CT. PET/CT examination 1 week after the initiation of lenvatinib treatment may predict treatment outcomes in patients with DTC. TRIAL REGISTRATION: This trial was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (number UMIN000022592) on 6 June, 2016.
  • Recent advances in artificial intelligence for cardiac CT: Enhancing diagnosis and prognosis prediction.
    Fuminari Tatsugami, Takeshi Nakaura, Masahiro Yanagawa, Shohei Fujita, Koji Kamagata, Rintaro Ito, Mariko Kawamura, Yasutaka Fushimi, Daiju Ueda, Yusuke Matsui, Akira Yamada, Noriyuki Fujima, Tomoyuki Fujioka, Taiki Nozaki, Takahiro Tsuboyama, Kenji Hirata, Shinji Naganawa
    Diagnostic and interventional imaging, 2023年07月04日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Recent advances in artificial intelligence (AI) for cardiac computed tomography (CT) have shown great potential in enhancing diagnosis and prognosis prediction in patients with cardiovascular disease. Deep learning, a type of machine learning, has revolutionized radiology by enabling automatic feature extraction and learning from large datasets, particularly in image-based applications. Thus, AI-driven techniques have enabled a faster analysis of cardiac CT examinations than when they are analyzed by humans, while maintaining reproducibility. However, further research and validation are required to fully assess the diagnostic performance, radiation dose-reduction capabilities, and clinical correctness of these AI-driven techniques in cardiac CT. This review article presents recent advances of AI in the field of cardiac CT, including deep-learning-based image reconstruction, coronary artery motion correction, automatic calcium scoring, automatic epicardial fat measurement, coronary artery stenosis diagnosis, fractional flow reserve prediction, and prognosis prediction, analyzes current limitations of these techniques and discusses future challenges.
  • In vivo imaging of acute physiological responses after treatment of cancer with near-infrared photoimmunotherapy
    Kohei Nakajima, Akiyo Sugikawa, Hironobu Yasui, Kei Higashikawa, Chie Suzuki, Takahiro Natsume, Motofumi Suzuki, Hideo Takakura, Mayu Tomita, Sachi Takahashi, Kenji Hirata, Yasuhiro Magata, Yuji Kuge, Mikako Ogawa
    Molecular Imaging and Biology, Springer Science and Business Media LLC, 2023年05月16日, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Clinical applications of artificial intelligence in liver imaging.
    Akira Yamada, Koji Kamagata, Kenji Hirata, Rintaro Ito, Takeshi Nakaura, Daiju Ueda, Shohei Fujita, Yasutaka Fushimi, Noriyuki Fujima, Yusuke Matsui, Fuminari Tatsugami, Taiki Nozaki, Tomoyuki Fujioka, Masahiro Yanagawa, Takahiro Tsuboyama, Mariko Kawamura, Shinji Naganawa
    La Radiologia medica, 2023年05月10日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, This review outlines the current status and challenges of the clinical applications of artificial intelligence in liver imaging using computed tomography or magnetic resonance imaging based on a topic analysis of PubMed search results using latent Dirichlet allocation. LDA revealed that "segmentation," "hepatocellular carcinoma and radiomics," "metastasis," "fibrosis," and "reconstruction" were current main topic keywords. Automatic liver segmentation technology using deep learning is beginning to assume new clinical significance as part of whole-body composition analysis. It has also been applied to the screening of large populations and the acquisition of training data for machine learning models and has resulted in the development of imaging biomarkers that have a significant impact on important clinical issues, such as the estimation of liver fibrosis, recurrence, and prognosis of malignant tumors. Deep learning reconstruction is expanding as a new technological clinical application of artificial intelligence and has shown results in reducing contrast and radiation doses. However, there is much missing evidence, such as external validation of machine learning models and the evaluation of the diagnostic performance of specific diseases using deep learning reconstruction, suggesting that the clinical application of these technologies is still in development.
  • Safety and efficacy of tisagenlecleucel in patients with relapsed or refractory B-cell lymphoma: the first real-world evidence in Japan.
    Hideki Goto, Toshio Kitawaki, Nobuharu Fujii, Koji Kato, Yasushi Onishi, Noriko Fukuhara, Takuji Yamauchi, Kazunori Toratani, Hiroki Kobayashi, Shota Yoshida, Masatoshi Shimo, Koichi Onodera, Hajime Senjo, Masahiro Onozawa, Kenji Hirata, Isao Yokota, Takanori Teshima
    International journal of clinical oncology, 28, 6, 816, 826, 2023年04月18日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Tisagenlecleucel, an autologous CD19-directed T-cell immunotherapy, can induce a durable response in adult patients with relapsed/refractory (r/r) B-cell lymphoma. METHODS: To elucidate the outcome of chimeric antigen receptor (CAR) T-cell therapy in Japanese, we retrospectively analyzed the outcomes of 89 patients who received tisagenlecleucel for r/r diffuse large B-cell lymphoma (n = 71) or transformed follicular lymphoma (n = 18). RESULTS: With a median follow-up of 6.6-months, 65 (73.0%) patients achieved a clinical response. The overall survival (OS) and event-free survival (EFS) rates at 12 months were 67.0% and 46.3%, respectively. Overall, 80 patients (89.9%) had cytokine release syndrome (CRS), and 6 patients (6.7%) had a grade ≥ 3 event. ICANS occurred in 5 patients (5.6%); only 1 patient had grade 4 ICANS. Representative infectious events of any grade were cytomegalovirus viremia, bacteremia and sepsis. The most common other adverse events were ALT elevation, AST elevation, diarrhea, edema, and creatinine elevation. No treatment-related mortality was observed. A Sub-analysis showed that a high metabolic tumor volume (MTV; ≥ 80 ml) and stable disease /progressive disease before tisagenlecleucel infusion were both significantly associated with a poor EFS and OS in a multivariate analysis (P < 0.05). Notably, the combination of these 2 factors efficiently stratified the prognosis of these patients (HR 6.87 [95% CI 2.4-19.65; P < 0.05] into a high-risk group). CONCLUSION: We report the first real-world data on tisagenlecleucel for r/r B-cell lymphoma in Japan. Tisagenlecleucel is feasible and effective, even in late line treatment. In addition, our results support a new algorithm for predicting the outcomes of tisagenlecleucel.
  • (第9回)全国核医学診療実態調査報告書
    西山 佳宏, 沖崎 貴琢, 乾 好貴, 大塚 秀樹, 高浪 健太郎, 中條 正豊, 中谷 航也, 野上 宗伸, 平田 健司, 前田 幸人, 吉村 真奈, 若林 大志, (公社)日本アイソトープ協会医学・薬学部会全国核医学診療実態調査専門委員会
    Radioisotopes, 72, 1, 49, 100, (公社)日本アイソトープ協会, 2023年03月
    日本語
  • Sunburst appearanceを呈する頭蓋骨腫瘤を契機に発見された神経芽腫の1例　　　　　　　　　　　　　　　
    北川 悠, 竹中 淳規, 渡邊 史郎, 平田 健司, 内山 裕子, 木村 理奈, 中川 純一, 池辺 洋平, 長谷河 昌孝, 澤井 彩織, 寺下 友佳代, 杉山 未奈子, 平林 真介, 長 祐子, 山口 秀, 真部 淳, 工藤 與亮
    北海道放射線医学雑誌, 3, 33, 36, (NPO)メディカルイメージラボ, 2023年03月, ［査読有り］
    日本語
  • (第9回)全国核医学診療実態調査報告書
    西山 佳宏, 沖崎 貴琢, 乾 好貴, 大塚 秀樹, 高浪 健太郎, 中條 正豊, 中谷 航也, 野上 宗伸, 平田 健司, 前田 幸人, 吉村 真奈, 若林 大志, (公社)日本アイソトープ協会医学・薬学部会全国核医学診療実態調査専門委員会
    Radioisotopes, 72, 1, 49, 100, (公社)日本アイソトープ協会, 2023年03月
    日本語
  • Four-dimensional quantitative analysis using FDG-PET in clinical cardiology.
    Nagara Tamaki, Kenji Hirata, Tomoya Kotani, Yoshitomo Nakai, Shigenori Matsushima, Kei Yamada
    Japanese Journal of Radiology, 41, 8, 831, 842, Springer Science and Business Media LLC, 2023年03月, ［査読有り］
    英語, 研究論文（学術雑誌）, Abstract

    Positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) has been commonly used in many oncological areas. High-resolution PET permits a three-dimensional analysis of FDG distributions on various lesions in vivo, which can be applied for tissue characterization, risk analysis, and treatment monitoring after chemoradiotherapy and immunotherapy. Metabolic changes can be assessed using the tumor absolute FDG uptake as standardized uptake value (SUV) and metabolic tumor volume (MTV). In addition, tumor heterogeneity assessment can potentially estimate tumor aggressiveness and resistance to chemoradiotherapy. Attempts have been made to quantify intratumoral heterogeneity using radiomics. Recent reports have indicated the clinical feasibility of a dynamic FDG PET-computed tomography (CT) in pilot cohort studies of oncological cases. Dynamic imaging permits the assessment of temporal changes in FDG uptake after administration, which is particularly useful for differentiating pathological from physiological uptakes with high diagnostic accuracy. In addition, several new parameters have been introduced for the in vivo quantitative analysis of FDG metabolic processes. Thus, a four-dimensional FDG PET-CT is available for precise tissue characterization of various lesions. This review introduces various new techniques for the quantitative analysis of FDG distribution and glucose metabolism using a four-dimensional FDG analysis with PET-CT. This elegant study reveals the important role of tissue characterization and treatment strategies in oncology.
  • MIP類似アルゴリズムによるFDG-PET体表画像の有用性　　　　　　　　　　　　　　　
    平田 健司, 木村 理奈, 唐 明輝, 渡邊 史郎, 竹中 淳規, 若林 直人, 杉森 博行, 吉村 高明, 工藤 與亮
    核医学, 60, Suppl., S208, S208, (一社)日本核医学会, 2023年
    日本語
  • SRCNNを用いた短時間収集PET画像の画質改善モデルの開発と定量性評価　　　　　　　　　　　　　　　
    遠藤 大輝, 吉村 高明, 唐 明輝, 杉森 博行, 長谷川 淳, 小亀 翔揮, 孫田 惠一, 木村 理奈, 渡邊 史郎, 平田 健司, 工藤 與亮
    核医学, 60, Suppl., S209, S209, (一社)日本核医学会, 2023年
    日本語
  • 切除不能/転移性PPGLにおける初回I-131MIBG治療による総糖代謝量の変化と予後の関係性の解析　　　　　　　　　　　　　　　
    竹中 淳規, 渡邊 史郎, 安部 崇重, 土川 貴裕, 竹内 啓, 平田 健司, 木村 理奈, 若林 直人, 篠原 信雄, 工藤 與亮
    核医学, 60, Suppl., S216, S216, (一社)日本核医学会, 2023年
    日本語
  • 褐色細胞腫・傍神経節腫に対するI-131MIBG治療の単回投与と複数回投与での有害事象発生率の検討　　　　　　　　　　　　　　　
    若林 直人, 渡邊 史郎, 安部 崇重, 竹中 淳規, 平田 健司, 篠原 信雄, 工藤 與亮
    核医学, 60, Suppl., S216, S216, (一社)日本核医学会, 2023年
    日本語
  • Neuroblastoma-related severe hypoperfusion in the cerebellum of an infant: A case of opsoclonus-myoclonus syndrome.
    Junki Takenaka, Kenji Hirata, Shiro Watanabe, Hideaki Shiraishi, Kohsuke Kudo
    Asia Oceania journal of nuclear medicine & biology, 11, 1, 93, 96, 2023年, ［国際誌］
    英語, A 2-year-old girl started to wobble without any specific triggers, so the patient was admitted to our hospital's pediatric department. The entire cerebellum showed severe atrophy on MRI and much lower uptake than that in the cerebral cortex on perfusion SPECT. The diagnosis of opsoclonus-myoclonus syndrome (OMS) was suspected. MRI visualized a small mass behind the inferior vena cava. Although its uptake on I-123 MIBG scintigraphy was inconclusive, the mass was surgically removed, and the diagnosis of neuroblastoma was pathologically confirmed. OMS is one of the paraneoplastic neurological syndromes with cerebellar ataxia, myoclonus of the trunk and extremities, and opsoclonus as its main symptoms. Approximately 50% of children cases with OMS are associated with neuroblastoma. The prognosis for neuroblastoma itself with OMS is relatively good, but the neurological prognosis is very poor. If there is decreased blood flow in the cerebellum of an infant, it may be necessary to search for neuroblastoma.
  • MIP類似アルゴリズムによるFDG-PET体表画像の有用性　　　　　　　　　　　　　　　
    平田 健司, 木村 理奈, 唐 明輝, 渡邊 史郎, 竹中 淳規, 若林 直人, 杉森 博行, 吉村 高明, 工藤 與亮
    核医学, 60, Suppl., S208, S208, (一社)日本核医学会, 2023年
    日本語
  • SRCNNを用いた短時間収集PET画像の画質改善モデルの開発と定量性評価　　　　　　　　　　　　　　　
    遠藤 大輝, 吉村 高明, 唐 明輝, 杉森 博行, 長谷川 淳, 小亀 翔揮, 孫田 惠一, 木村 理奈, 渡邊 史郎, 平田 健司, 工藤 與亮
    核医学, 60, Suppl., S209, S209, (一社)日本核医学会, 2023年
    日本語
  • Estimation of Amyloid-β Positivity Using QSM Images Considering Age Information.
    Tsubasa Kunieda, Ren Togo, Noriko Nishioka, Yukie Shimizu, Shiro Watanabe, Kenji Hirata, Keisuke Maeda, Takahiro Ogawa 0001, Kohsuke Kudo, Miki Haseyama
    ICCE-Taiwan, 165, 166, 2023年
    研究論文（国際会議プロシーディングス）
  • Prognostic value of [18F]FDG-PET prior to [131I]MIBG treatment for pheochromocytoma and paraganglioma (PPGL).
    Junki Takenaka, Shiro Watanabe, Takashige Abe, Kenji Hirata, Yuko Uchiyama, Rina Kimura, Nobuo Shinohara, Kohsuke Kudo
    Annals of nuclear medicine, 2022年10月27日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: Pheochromocytomas and paragangliomas (PPGLs) are rare tumors arising from the neural crest cells that form the sympathetic and parasympathetic nervous systems. Radiotherapy with [131I]metaiodobenzylguanidine (MIBG) is recommended for unresectable PPGLs. We investigated the usefulness of the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) derived from [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET) for predicting the prognosis of patients with unresectable PPGL(s) before receiving [131I]MIBG therapy. PATIENTS AND METHODS: We retrospectively analyzed the cases of 25 patients with unresectable PPGLs treated with [131I]MIBG at our hospital between 2001 and 2020. The MTV and TLG were measured in reference to liver accumulation. We divided the patients into two groups based on median values for the maximum standardized uptake value (SUVmax), MTV, and TLG, and evaluated between-group differences using log-rank tests. Cox proportional hazards models were used to determine whether there were significant differences in prognosis with respect to tumor type (pheochromocytoma vs. paraganglioma), site of metastasis, age, past treatment (chemotherapy, external radiation or [131I]MIBG treatment before the current [131I]MIBG treatment), urinary catecholamine, SUVmax, MTV, and TLG. RESULTS: The median follow-up time was 42 months (range 2-136 months). The median overall survival was 63 months. The overall survival (OS) was significantly shorter in the high-MTV group (log-rank test, p = 0.049) and the high-TLG group (p = 0.049), with no significant difference between the high- and low-SUVmax groups (p = 0.19). Likewise, there was no significant difference in prognosis according to pheochromocytoma or paraganglioma, metastasis location, age, or prior chemotherapy. A history of external radiation before [131I]MIBG treatment was associated with a significantly worse prognosis (hazard ration [HR] = 7.95, p = 0.0018). Urinary adrenaline and noradrenaline were not significant prognostic factors (p = 0.70, p = 0.25, respectively), but urinary dopamine did predict a worse outcome (p = 0.022). There was no increased risk of death for higher SUVmax or TLG (p = 0.63 and 0.057, respectively), but higher MTV did predict a worse outcome (HR = 7.27, p = 0.029). CONCLUSION: High MTV and high TLG were significantly associated with a poor prognosis after [131I]MIBG therapy for PPGLs. Other treatment strategies for such patients may need to be explored.
  • Effect of radioactivity outside the field of view on image quality of dedicated breast positron emission tomography: preliminary phantom and clinical studies.
    Yoko Satoh, Masamichi Imai, Chihiro Ikegawa, Kenji Hirata, Norifumi Abo, Mao Kusuzaki, Noriko Oyama-Manabe, Hiroshi Onishi
    Annals of nuclear medicine, 36, 12, 1010, 1018, 2022年10月08日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: Semi-quantitative positron emission tomography (PET) values, such as the maximum standardized uptake value (SUVmax), are widely used to identify malignant lesions and evaluate the response to treatment. The image quality of ring-shaped dedicated breast positron emission tomography (dbPET) has been known to decrease the closer it is to the detector's edge. This study aimed to investigate the effect of radioactivity (RI) outside the detector field of view (FOV) on the image quality of the ring-shaped dbPET. METHODS: A breast phantom containing the left myocardium, which was prepared using a 3D printer, filled with 18F-fluorodeoxyglucose (FDG) solution with various RI concentration ratios (RCRs) of myocardium to background and scanned with the edge of an apex positioned exactly in line with the edge of the FOV of the dbPET scanner. The phantom image quality was visually and quantitatively evaluated. Following the phantom study, left-right breast differences (the left breast uptake ratio to the right breast (LUR)) on clinical dbPET images of 74 women were quantitatively evaluated. The relationships between these parameters, clinical indices, and FDG uptake in the left myocardium on PET/computed tomography (CT) images were analyzed. RESULTS: The phantom study showed that the higher the RCR of the myocardium and the closer it is to the top edge of the phantom, the higher is the pixel value of the dbPET images. In a clinical study, LUR was significantly correlated with myocardial SUVmax (r = 0.96, p < 0.0001) and metabolic myocardial volume (r = 0.63, p = 0.001) for whole-body PET/CT imaging. Although no significant correlations were found between LUR and age (r = 0.05, p = 0.6865), body mass index (r = 0.03, p = 0.8178), or distance between the left myocardial apex and chest wall (r = 0.16, p = 0.1667). CONCLUSIONS: FDG uptake in the myocardium affected dbPET images of the left breast, especially near the chest wall. Further, the effect of RI outside the FOV, such as in the myocardium, must be considered in the quantitative evaluation of breast cancer using dbPET.
  • Utility of the deep learning technique for the diagnosis of orbital invasion on CT in patients with a nasal or sinonasal tumor.
    Junichi Nakagawa, Noriyuki Fujima, Kenji Hirata, Minghui Tang, Satonori Tsuneta, Jun Suzuki, Taisuke Harada, Yohei Ikebe, Akihiro Homma, Satoshi Kano, Kazuyuki Minowa, Kohsuke Kudo
    Cancer imaging : the official publication of the International Cancer Imaging Society, 22, 1, 52, 52, 2022年09月22日, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: In nasal or sinonasal tumors, orbital invasion beyond periorbita by the tumor is one of the important criteria in the selection of the surgical procedure. We investigated the usefulness of the convolutional neural network (CNN)-based deep learning technique for the diagnosis of orbital invasion, using computed tomography (CT) images. METHODS: A total of 168 lesions with malignant nasal or sinonasal tumors were divided into a training dataset (n = 119) and a test dataset (n = 49). The final diagnosis (invasion-positive or -negative) was determined by experienced radiologists who carefully reviewed all of the CT images. In a CNN-based deep learning analysis, a slice of the square target region that included the orbital bone wall was extracted and fed into a deep-learning training session to create a diagnostic model using transfer learning with the Visual Geometry Group 16 (VGG16) model. The test dataset was subsequently tested in CNN-based diagnostic models and by two other radiologists who were not specialized in head and neck radiology. At approx. 2 months after the first reading session, two radiologists again reviewed all of the images in the test dataset, referring to the diagnoses provided by the trained CNN-based diagnostic model. RESULTS: The diagnostic accuracy was 0.92 by the CNN-based diagnostic models, whereas the diagnostic accuracies by the two radiologists at the first reading session were 0.49 and 0.45, respectively. In the second reading session by two radiologists (diagnosing with the assistance by the CNN-based diagnostic model), marked elevations of the diagnostic accuracy were observed (0.94 and 1.00, respectively). CONCLUSION: The CNN-based deep learning technique can be a useful support tool in assessing the presence of orbital invasion on CT images, especially for non-specialized radiologists.
  • AIによる肝臓セグメンテーションの性能評価と肝臓体積の経時的変化　　　　　　　　　　　　　　　
    木村 理奈, 平田 健司, 常田 慧徳, 竹中 淳規, 渡邊 史郎, 阿保 大介, 工藤 與亮
    日本医学放射線学会秋季臨床大会抄録集, 59回, S403, S403, (公社)日本医学放射線学会, 2022年09月
    日本語
  • Recent topics of the clinical utility of PET/MRI in oncology and neuroscience
    Yuji Nakamoto, Kazuhiro Kitajima, Akira Toriihara, Masatoyo Nakajo, Kenji Hirata
    Annals of Nuclear Medicine, 36, 9, 798, 803, Springer Science and Business Media LLC, 2022年09月
    研究論文（学術雑誌）
  • Identification of patients with Graves' disease who benefit from high-dose radioactive iodine therapy.
    Shiro Watanabe, Shozo Okamoto, Kazumasa Akikawa, Noriyuki Miyamoto, Miyuki Okamura-Kawasaki, Yuko Uchiyama, Junki Takenaka, Takuya Toyonaga, Kenji Hirata, Kohsuke Kudo
    Annals of nuclear medicine, 2022年08月16日, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: Radioactive iodine (RAI) therapy is a useful treatment for Graves' disease (GD). Most RAI sessions administer ≤ 500 MBq of iodine (I)-131. Sometimes patients require repeated RAI, often for longer periods of remission. We investigated the characteristics of patients for whom high dose (mostly 1110 MBq of I-131) RAI was effective as RAI therapy for GD. METHODS: We retrospectively analyzed the cases of 79 patients who underwent RAI for GD in a multicenter setting. We divided the patients into two groups based on the I-131 dose administered: the low dose (LD) group who received ≤ 500 MBq (n = 44) and the high dose (HD) group who received > 500 MBq (n = 35). The therapeutic effect was defined as achieving remission and reaching the point of participating in thyroid hormone replacement therapy within 1 year after RAI. We compared the LD and HD groups' remission rates and conducted a multivariate logistic regression analysis of predictive factors for remission. In a simulation, using the formula for predicting the probability of remission obtained from the analysis results, we estimated how much the remission rate would change if the I-131 dose is increased from 500 to 1110 MBq. RESULTS: The mean ± standard deviation I-131 dose administered in the LD group was 480 ± 6 MBq, and that of the HD group was 1054 ± 265 MBq. Thirty-five patients (80%) in the LD group and 26 patients (74%) in the HD group achieved remission; this difference in the remission rate was not significant. The multivariate analysis results demonstrated that the absorbed dose and thyroid-stimulating antibody (TSAb) were independent predictors of remission. Seven patients (8.9%) showed an increased probability of remission from < 50% to > 50% when the higher RAI dose was applied (1110 MBq instead of 500 MBq). The thyroid volume and TSAb values in these patients were relatively large at 54.7 ± 34.2 mL and 1378.4 ± 586.3%, respectively. CONCLUSION: Although the overall remission rate was not significantly different between the patients who received high- or low-dose I-131, treatment with high-dose RAI may improve the probability of remission in patients with a massive thyroid volume and/or high-TSAb Graves' disease.
  • バセドウ病に対するHigh dose I-131治療による治療効果の改善　　　　　　　　　　　　　　　
    渡邊 史郎, 岡本 祥三, 秋川 和聖, 内山 裕子, 竹中 淳規, 平田 健司, 工藤 與亮
    核医学, 59, Suppl., S463, S463, (一社)日本核医学会, 2022年08月
    日本語
  • 【脳腫瘍の放射線治療と画像診断:画像診断医が伝えたいこと】脳腫瘍に対する核医学の役割 再発・壊死の鑑別や核医学治療の可能性
    平田 健司, 竹中 淳規, 山口 秀, 志賀 哲, 豊永 拓哉, 工藤 與亮
    臨床放射線, 67, 7, 683, 692, 金原出版(株), 2022年07月
    日本語
  • Reduction of tumor hypoxia by anti-PD-1 therapy assessed using pimonidazole and [18F]FMISO
    Kohei Nakajima, Mitsunori Homma, Motofumi Suzuki, Yuta Yokouchi, Takuma Matsuda, Hideo Takakura, Kenji Hirata, Yuji Kuge, Mikako Ogawa
    Nuclear Medicine and Biology, 108-109, 85, 92, Elsevier BV, 2022年05月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, INTRODUCTION: Hypoxia is common in solid tumors and creates an immunosuppressive environment that leads to resistance to immunotherapy, such as an anti-programmed death receptor-1 (PD-1) therapy. It has been suggested that anti-PD-1 therapy may reduce tumor hypoxia by remodeling the tumor vasculature; however, it is unclear how anti-PD-1 therapy reduces hypoxia over time. Therefore, we investigated the relationship between hypoxia and immune activation by anti-PD-1 therapy in murine cancer models. METHODS: Anti-PD-1 antibody was injected to CT26- and MC38-tumor-bearing mice on days 0 and 5. Tumor hypoxia was non-invasively evaluated using positron emission tomography (PET) with [18F]fluoromisonidazole ([18F]FMISO) on days 3 and 7. Histological analysis was conducted to investigate the infiltration of immune cells in [18F]FMISO-accumulated hypoxic area. In addition, the immune cell population in tumors and the percentages of cancer and immune cells under hypoxic conditions were analyzed at single-cell level using flow cytometry. RESULTS: Flow cytometric analysis of CT26 tumors on day 3 showed that anti-PD-1 therapy reduced hypoxia without inhibition of tumor growth. In addition, the infiltration of CD8+ T cells was increased in treated tumors. In contrast to CT26 tumors, the percentage of hypoxic cells in MC38 tumors did not change on days 3 and 7, and there was minimal immune activation induced by anti-PD-1 antibody. Changes in hypoxia in CT26 tumors were not detected by [18F]FMISO-PET, but autoradiogram showed that [18F]FMISO accumulated in immunosuppressed areas, where the infiltration of immune cells was relatively low. CONCLUSION: Reduction of hypoxia was induced in CT26 tumor, in which adequate immune response to anti-PD-1 therapy was exhibited, at an early time point before suppression of tumor growth. Our findings suggest that anti-PD-1 therapy can create a tumor microenvironment that facilitates immune activation by reducing hypoxia.
  • Medical Radiation Exposure Reduction in PET via Super-Resolution Deep Learning Model
    Takaaki Yoshimura, Atsushi Hasegawa, Shoki Kogame, Keiichi Magota, Rina Kimura, Shiro Watanabe, Kenji Hirata, Hiroyuki Sugimori
    Diagnostics, 12, 4, 872, 872, MDPI AG, 2022年03月31日
    研究論文（学術雑誌）, In positron emission tomography (PET) imaging, image quality correlates with the injected [18F]-fluorodeoxyglucose (FDG) dose and acquisition time. If image quality improves from short-acquisition PET images via the super-resolution (SR) deep learning technique, it is possible to reduce the injected FDG dose. Therefore, the aim of this study was to clarify whether the SR deep learning technique could improve the image quality of the 50%-acquisition-time image to the level of that of the 100%-acquisition-time image. One-hundred-and-eight adult patients were enrolled in this retrospective observational study. The supervised data were divided into nine subsets for nested cross-validation. The mean peak signal-to-noise ratio and structural similarity in the SR-PET image were 31.3 dB and 0.931, respectively. The mean opinion scores of the 50% PET image, SR-PET image, and 100% PET image were 3.41, 3.96, and 4.23 for the lung level, 3.31, 3.80, and 4.27 for the liver level, and 3.08, 3.67, and 3.94 for the bowel level, respectively. Thus, the SR-PET image was more similar to the 100% PET image and subjectively improved the image quality, as compared to the 50% PET image. The use of the SR deep-learning technique can reduce the injected FDG dose and thus lower radiation exposure.
  • 肺癌の再発・転移が疑われた後縦隔FDG陽性病変の診断に骨髄シンチグラフィが有用であった一例　　　　　　　　　　　　　　　
    眞島 隆成, 竹中 淳規, 渡邊 史郎, 内山 裕子, 木村 理奈, 榊原 純, 平田 健司, 工藤 與亮
    北海道放射線医学雑誌, 2, 29, 33, (NPO)メディカルイメージラボ, 2022年03月
    日本語
  • 免疫チェックポイント阻害剤が腫瘍内の低酸素状態に及ぼす影響に関する検討　　　　　　　　　　　　　　　
    本間 充憲, 中島 孝平, 鈴木 基史, 横内 勇太, 松田 拓真, 高倉 栄男, 平田 健司, 久下 裕司, 小川 美香子
    日本薬学会年会要旨集, 142年会, 26H, pm06S, (公社)日本薬学会, 2022年03月
    日本語
  • 演繹法と帰納法の視点から見た医療AI　　　　　　　　　　　　　　　
    平田 健司, 杉森 博行, 唐 明輝, 中谷 純, 小笠原 克彦, 豊永 拓哉, 工藤 與亮
    北海道放射線医学雑誌, 2, 1, 6, (NPO)メディカルイメージラボ, 2022年03月
    日本語
  • An open-label, single-arm, multi-center, phase II clinical trial of single-dose [131I]meta-iodobenzylguanidine therapy for patients with refractory pheochromocytoma and paraganglioma
    Anri Inaki, Tohru Shiga, Yoshito Tsushima, Megumi Jinguji, Hiroshi Wakabayashi, Daiki Kayano, Norihito Akatani, Takafumi Yamase, Yuji Kunita, Satoru Watanabe, Tomo Hiromasa, Hiroshi Mori, Kenji Hirata, Shiro Watanabe, Tetsuya Higuchi, Hiroyasu Tomonaga, Seigo Kinuya
    Annals of Nuclear Medicine, 36, 3, 267, 278, Springer Science and Business Media LLC, 2022年03月, ［査読有り］
    研究論文（学術雑誌）, Abstract

    Objective

    In this phase II study, we aimed to investigate the efficacy and safety of single-dose [131I]meta-iodobenzylguanidine (131I-mIBG) therapy in patients with refractory pheochromocytoma and paraganglioma (PPGL).

    Patients and methods

    This study was designed as an open-label, single-arm, multi-center, phase II clinical trial. The enrolled patients were administered 7.4 GBq of 131I-mIBG. Its efficacy was evaluated 12 and 24 weeks later, and its safety was monitored continuously until the end of the study. We evaluated the biochemical response rate as the primary endpoint using the one-sided exact binomial test based on the null hypothesis (≤ 5%).

    Results

    Seventeen patients were enrolled in this study, of which 16 were treated. The biochemical response rate (≥ 50% decrease in urinary catecholamines) was 23.5% (90% confidence interval: 8.5–46.1%, p = 0.009). The radiographic response rates, determined with CT/MRI according to the response evaluation criteria in solid tumors (RECIST) version 1.1 and 123I-mIBG scintigraphy were 5.9% (0.3%–25.0%) and 29.4% (12.4%–52.2%), respectively. The most frequent non-hematologic treatment-emergent adverse events (TEAEs) were gastrointestinal symptoms including nausea, appetite loss, and constipation, which were, together, observed in 15 of 16 patients. Hematologic TEAEs up to grade 3 were observed in 14 of 16 patients. No grade 4 or higher TEAEs were observed. All patients had experienced at least one TEAE, but no fatal or irreversible TEAEs were observed.

    Conclusion

    A single dose 131I-mIBG therapy was well tolerated by patients with PPGL, and statistically significantly reduced catecholamine levels compared to the threshold response rate, which may lead to an improved prognosis for these patients.
  • Artificial intelligence for nuclear medicine in oncology.
    Kenji Hirata, Hiroyuki Sugimori, Noriyuki Fujima, Takuya Toyonaga, Kohsuke Kudo
    Annals of nuclear medicine, 36, 2, 123, 132, 2022年01月14日, ［査読有り］, ［招待有り］, ［筆頭著者, 責任著者］, ［国内誌］
    英語, 研究論文（学術雑誌）, As in all other medical fields, artificial intelligence (AI) is increasingly being used in nuclear medicine for oncology. There are many articles that discuss AI from the viewpoint of nuclear medicine, but few focus on nuclear medicine from the viewpoint of AI. Nuclear medicine images are characterized by their low spatial resolution and high quantitativeness. It is noted that AI has been used since before the emergence of deep learning. AI can be divided into three categories by its purpose: (1) assisted interpretation, i.e., computer-aided detection (CADe) or computer-aided diagnosis (CADx). (2) Additional insight, i.e., AI provides information beyond the radiologist's eye, such as predicting genes and prognosis from images. It is also related to the field called radiomics/radiogenomics. (3) Augmented image, i.e., image generation tasks. To apply AI to practical use, harmonization between facilities and the possibility of black box explanations need to be resolved.
  • DWI-related texture analysis for prostate cancer: differences in correlation with histological aggressiveness and data repeatability between peripheral and transition zones.
    Chie Tsuruta, Kenji Hirata, Kohsuke Kudo, Naoya Masumori, Masamitsu Hatakenaka
    European radiology experimental, 6, 1, 1, 1, 2022年01月12日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: We investigated the correlation between texture features extracted from apparent diffusion coefficient (ADC) maps or diffusion-weighted images (DWIs), and grade group (GG) in the prostate peripheral zone (PZ) and transition zone (TZ), and assessed reliability in repeated examinations. METHODS: Patients underwent 3-T pelvic magnetic resonance imaging (MRI) before radical prostatectomy with repeated DWI using b-values of 0, 100, 1,000, and 1,500 s/mm2. Region of interest (ROI) for cancer was assigned to the first and second DWI acquisition separately. Texture features of ROIs were extracted from comma-separated values (CSV) data of ADC maps generated from several sets of two b-value combinations and DWIs, and correlation with GG, discrimination ability between GG of 1-2 versus 3-5, and data repeatability were evaluated in PZ and TZ. RESULTS: Forty-four patients with 49 prostate cancers met the eligibility criteria. In PZ, ADC 10% and 25% based on ADC map of two b-value combinations of 100 and 1,500 s/mm2 and 10% based on ADC map with b-value of 0 and 1,500 s/mm2 showed significant correlation with GG, acceptable discrimination ability, and good repeatability. In TZ, higher-order texture feature of busyness extracted from ADC map of 100 and 1,500 s/mm2, and high gray-level run emphasis, short-run high gray-level emphasis, and high gray-level zone emphasis from DWI with b-value of 100 s/mm2 demonstrated significant correlation, excellent discrimination ability, but moderate repeatability. CONCLUSIONS: Some DWI-related features showed significant correlation with GG, acceptable to excellent discrimination ability, and moderate to good data repeatability in prostate cancer, and differed between PZ and TZ.
  • Prediction of Amyloid-β Positivity Using QSM Images Based on Bootstrap Your Own Latent.
    Tsubasa Kunieda, Ren Togo, Noriko Nishioka, Yukie Shimizu, Shiro Watanabe, Kenji Hirata, Keisuke Maeda, Takahiro Ogawa 0001, Kohsuke Kudo, Miki Haseyama
    GCCE, 137, 138, IEEE, 2022年
    研究論文（国際会議プロシーディングス）
  • An open-label, single-arm, multi-center, phase II clinical trial of single-dose [131I]meta-iodobenzylguanidine therapy for patients with refractory pheochromocytoma and paraganglioma.
    Anri Inaki, Tohru Shiga, Yoshito Tsushima, Megumi Jinguji, Hiroshi Wakabayashi, Daiki Kayano, Norihito Akatani, Takafumi Yamase, Yuji Kunita, Satoru Watanabe, Tomo Hiromasa, Hiroshi Mori, Kenji Hirata, Shiro Watanabe, Tetsuya Higuchi, Hiroyasu Tomonaga, Seigo Kinuya
    Annals of nuclear medicine, 36, 3, 267, 278, 2021年12月06日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: In this phase II study, we aimed to investigate the efficacy and safety of single-dose [131I]meta-iodobenzylguanidine (131I-mIBG) therapy in patients with refractory pheochromocytoma and paraganglioma (PPGL). PATIENTS AND METHODS: This study was designed as an open-label, single-arm, multi-center, phase II clinical trial. The enrolled patients were administered 7.4 GBq of 131I-mIBG. Its efficacy was evaluated 12 and 24 weeks later, and its safety was monitored continuously until the end of the study. We evaluated the biochemical response rate as the primary endpoint using the one-sided exact binomial test based on the null hypothesis (≤ 5%). RESULTS: Seventeen patients were enrolled in this study, of which 16 were treated. The biochemical response rate (≥ 50% decrease in urinary catecholamines) was 23.5% (90% confidence interval: 8.5-46.1%, p = 0.009). The radiographic response rates, determined with CT/MRI according to the response evaluation criteria in solid tumors (RECIST) version 1.1 and 123I-mIBG scintigraphy were 5.9% (0.3%-25.0%) and 29.4% (12.4%-52.2%), respectively. The most frequent non-hematologic treatment-emergent adverse events (TEAEs) were gastrointestinal symptoms including nausea, appetite loss, and constipation, which were, together, observed in 15 of 16 patients. Hematologic TEAEs up to grade 3 were observed in 14 of 16 patients. No grade 4 or higher TEAEs were observed. All patients had experienced at least one TEAE, but no fatal or irreversible TEAEs were observed. CONCLUSION: A single dose 131I-mIBG therapy was well tolerated by patients with PPGL, and statistically significantly reduced catecholamine levels compared to the threshold response rate, which may lead to an improved prognosis for these patients.
  • The prognostic improvement of add-on bevacizumab for progressive disease during concomitant temozolomide and radiation therapy in patients with glioblastoma and anaplastic astrocytoma
    Shigeru Yamaguchi, Yukitomo Ishi, Hiroaki Motegi, Michinari Okamoto, Hiroyuki Kobayashi, Kenji Hirata, Yoshitaka Oda, Shinya Tanaka, Shunsuke Terasaka, Kiyohiro Houkin
    Journal of Neurosurgical Sciences, 64, 6, 502, 508, Edizioni Minerva Medica, 2021年12月01日
    英語, 研究論文（学術雑誌）
  • SiPM-PET/CT装置を用いた冠動脈18F-FDG集積の再現性評価　　　　　　　　　　　　　　　
    渡邊 史郎, 納谷 昌直, 孫田 恵一, 真鍋 治, 新山 大樹, 平田 健司, 内山 裕子, 竹中 淳規, 工藤 與亮
    核医学, 58, Suppl., S210, S210, (一社)日本核医学会, 2021年10月
    日本語
  • FDG-PET/CTのレポート上のSUVmaxを利用して解剖学用語を機械学習させる検討　　　　　　　　　　　　　　　
    平田 健司, 渡邊 史郎, 内山 裕子, 竹中 淳規, 木村 理奈, 眞島 隆成, 孫田 恵一, 工藤 與亮
    核医学, 58, Suppl., S225, S225, (一社)日本核医学会, 2021年10月
    日本語
  • 待機時間2時間は充分か 顎骨SPECT定量解析における撮像待機時間の研究　　　　　　　　　　　　　　　
    秦 浩信, 下村 悟史, 今待 賢治, 舩山 恭祐, 浅香 卓哉, 佐藤 淳, 平田 健司, 松坂 方士, 盛 洋一, 南部 敏和, 北川 善政
    核医学, 58, Suppl., S216, S216, (一社)日本核医学会, 2021年10月
    日本語
  • Prognostic Impact of Metabolic Heterogeneity in Patients With Newly Diagnosed Multiple Myeloma Using 18F-FDG PET/CT.
    Toshiki Terao, Youichi Machida, Kenji Hirata, Ayumi Kuzume, Rikako Tabata, Takafumi Tsushima, Daisuke Miura, Kentaro Narita, Masami Takeuchi, Ukihide Tateishi, Kosei Matsue
    Clinical nuclear medicine, 46, 10, 790, 796, 2021年10月01日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: This study aimed to investigate the prognostic impact of metabolic heterogeneity (MH) in patients with multiple myeloma (MM). PATIENTS AND METHODS: We retrospectively analyzed MH with 18F-FDG PET/CT in 203 patients with newly diagnosed MM. Metabolic heterogeneity was estimated using the area under the curve of the cumulative SUV volume histogram. To evaluate MH, we selected 2 lesions: "MH-SUVmax," a lesion with SUVmax, and "MH-metabolic tumor volume (MTV)," a lesion with the largest MTV. RESULTS: Metabolic heterogeneity from an MH-SUVmax lesion showed more prognostic relevance than that from a lesion with the largest MTV. The progression-free survival (PFS) and overall survival (OS) rates were significantly lower in the high-MH-SUVmax group than in the low-MH-SUVmax group (median PFS: 25.2 vs 33.9 months; median OS: 41.6 vs 112.0 months; P = 0.004 and 0.046, respectively), whereas high MH-SUVmax retained independent prognostic power on multivariate analysis. Even among patients with high whole-body MTV, those with high MH-SUVmax tended to show poorer prognosis than those without (median PFS, 23.8 vs 30.2 months; P = 0.085). Moreover, patients with high MH-SUVmax and high-risk cytogenetic abnormalities showed dismal outcomes even with standard treatment (median PFS and OS, 10.0 and 33.3 months, respectively). CONCLUSIONS: Our results suggested that high MH-SUVmax based on pretreatment with 18F-FDG PET/CT is a novel prognostic factor for cases of MM.
  • Predicting tumor response and prognosis to neoadjuvant chemotherapy in esophageal squamous cell carcinoma patients using PERCIST: a multicenter study in Japan.
    Hayato Kaida, Kazuhiro Kitajima, Masatoyo Nakajo, Mana Ishibashi, Tomoyuki Matsunaga, Ryogo Minamimoto, Kenji Hirata, Koya Nakatani, Ao Hung, Satoshi Hattori, Takushi Yasuda, Kazunari Ishii
    European journal of nuclear medicine and molecular imaging, 48, 11, 3666, 3682, 2021年10月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: To investigate the usefulness of the positron emission tomography response criteria in solid tumors 1.0 (PERCIST1.0) for predicting tumor response to neoadjuvant chemotherapy and prognosis and determine whether PERCIST improvements are necessary for esophageal squamous cell carcinoma (ESCC) patients. PATIENTS AND METHODS: We analyzed the cases of 177 ESCC patients and examined the association between PERCIST and their pathological responses. Associations of whole-PERCIST with progression-free survival (PFS) and overall survival (OS) were evaluated by a Kaplan-Meier analysis and Cox proportional hazards model. To investigate potential PERCIST improvements, we used the survival tree technique to understand patients' prognoses. RESULTS: There were significant correlations between the pathologic response and PERCIST of primary tumor (p < 0.001). The optimal cutoff value of the primary tumors' SULpeak response to classify pathologic responses was -50.0%. The diagnostic accuracy of SULpeak response was 87.3% sensitivity, 54.1% specificity, 68.9% accuracy, positive predictive value 60.5%, and negative predictive value 84.1%. Whole-PERCIST was significantly associated with PFS and OS. The survival tree results indicated that a high reduction of the whole SULpeak response was significantly correlated with the patients' prognoses. The cutoff values for the separation of prognoses were - 52.5 for PFS and - 47.1% for OS. CONCLUSION: PERCIST1.0 can help predict tumor responses and prognoses. However, 18F-FDG-PET/CT tends to underestimate residual tumors in histopathological response evaluations. Modified PERCIST, in which the partial metabolic response is further classified by the SULpeak response (-50%), might be more appropriate than PERCIST1.0 for evaluating tumor responses and stratifying high-risk patients for recurrence and poor prognosis.
  • Determination of brain tumor recurrence using 11 C-methionine positron emission tomography after radiotherapy.
    Shigeru Yamaguchi, Kenji Hirata, Michinari Okamoto, Eku Shimosegawa, Jun Hatazawa, Ryuichi Hirayama, Naoki Kagawa, Haruhiko Kishima, Noboru Oriuchi, Masazumi Fujii, Kentaro Kobayashi, Hiroyuki Kobayashi, Shunsuke Terasaka, Ken-Ichi Nishijima, Yuji Kuge, Yoichi M Ito, Hiroshi Nishihara, Nagara Tamaki, Tohru Shiga
    Cancer science, 112, 10, 4246, 4256, 2021年10月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, We conducted a prospective multicenter trial to compare the usefulness of 11 C-methionine (MET) and 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for identifying tumor recurrence. Patients with clinically suspected tumor recurrence after radiotherapy underwent both 11 C-MET and 18 F-FDG PET. When a lesion showed a visually detected uptake of either tracer, it was surgically resected for histopathological analysis. Patients with a lesion negative to both tracers were revaluated by magnetic resonance imaging (MRI) at 3 months after the PET studies. The primary outcome measure was the sensitivity of each tracer in cases with histopathologically confirmed recurrence, as determined by the McNemar test. Sixty-one cases were enrolled, and 56 cases could be evaluated. The 38 cases where the lesions showed uptake of either 11 C-MET or 18 F-FDG underwent surgery; 32 of these cases were confirmed to be subject to recurrence. Eighteen cases where the lesions showed uptake of neither tracer received follow-up MRI; the lesion size increased in one of these cases. Among the cases with histologically confirmed recurrence, the sensitivities of 11 C-MET PET and 18 F-FDG PET were 0.97 (32/33, 95% confidence interval [CI]: 0.85-0.99) and 0.48 (16/33, 95% CI: 0.33-0.65), respectively, and the difference was statistically significant (P < .0001). The diagnostic accuracy of 11 C-MET PET was significantly better than that of 18 F-FDG PET (87.5% vs. 69.6%, P = .033). No examination-related adverse events were observed. The results of the study demonstrated that 11 C-MET PET was superior to 18 F-FDG PET for discriminating between tumor recurrence and radiation-induced necrosis.
  • Correlation of active contact location with weight gain after subthalamic nucleus deep brain stimulation: a case series.
    Katsuki Eguchi, Shinichi Shirai, Masaaki Matsushima, Takahiro Kano, Kazuyoshi Yamazaki, Shuji Hamauchi, Toru Sasamori, Toshitaka Seki, Kenji Hirata, Mayumi Kitagawa, Mika Otsuki, Tohru Shiga, Kiyohiro Houkin, Hidenao Sasaki, Ichiro Yabe
    BMC neurology, 21, 1, 351, 351, 2021年09月13日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Weight gain (WG) is a frequently reported side effect of subthalamic deep brain stimulation; however, the underlying mechanisms remain unclear. The active contact locations influence the clinical outcomes of subthalamic deep brain stimulation, but it is unclear whether WG is directly associated with the active contact locations. We aimed to determine whether WG is associated with the subthalamic deep brain stimulation active contact locations. METHODS: We enrolled 14 patients with Parkinson's disease who underwent bilateral subthalamic deep brain stimulation between 2013 and 2019. Bodyweight and body mass index were measured before and one year following the surgery. The Lead-DBS Matlab toolbox was used to determine the active contact locations based on magnetic resonance imaging and computed tomography. We also created sweet spot maps for WG using voxel-wise statistics, based on volume of tissue activation and the WG of each patient. Fluorodeoxyglucose-positron emission tomography data were also acquired before and one year following surgery, and statistical parametric mapping was used to evaluate changes in brain metabolism. We examined which brain regions' metabolism fluctuation significantly correlated with increased body mass index scores and positron emission tomography data. RESULTS: One year after surgery, the body mass index increase was 2.03 kg/m2. The sweet spots for WG were bilateral, mainly located dorsally outside of the subthalamic nucleus (STN). Furthermore, WG was correlated with increased metabolism in the left limbic and associative regions, including the middle temporal gyrus, inferior frontal gyrus, and orbital gyrus. CONCLUSIONS: Although the mechanisms underlying WG following subthalamic deep brain stimulation are possibly multifactorial, our findings suggest that dorsal stimulation outside of STN may lead to WG. The metabolic changes in limbic and associative cortical regions after STN-DBS may also be one of the mechanisms underlying WG. Further studies are warranted to confirm whether dorsal stimulation outside of STN changes the activities of these cortical regions.
  • Association of high serum soluble interleukin 2 receptor levels with risk of adverse events in cardiac sarcoidosis.
    Yuta Kobayashi, Takuma Sato, Toshiyuki Nagai, Kenji Hirata, Satonori Tsuneta, Yoshiya Kato, Hirokazu Komoriyama, Kiwamu Kamiya, Takao Konishi, Kazunori Omote, Hiroshi Ohira, Kohsuke Kudo, Satoshi Konno, Toshihisa Anzai
    ESC heart failure, 8, 6, 5282, 5292, 2021年09月12日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, AIMS: Although soluble interleukin 2 receptor (sIL-2R) is a potentially useful biomarker in the diagnosis and evaluation of disease severity in patients with sarcoidosis, its prognostic implication in patients with cardiac sarcoidosis (CS) is unclear. We sought to investigate whether sIL-2R was associated with clinical outcomes and to clarify the relationship between sIL-2R levels and disease activity in patients with CS. METHODS AND RESULTS: We examined 83 consecutive patients with CS in our hospital who had available serum sIL-2R data between May 2003 and February 2020. The primary outcome was a composite of advanced atrioventricular block, ventricular tachycardia or ventricular fibrillation, heart failure hospitalization, and all-cause death. Inflammatory activity in the myocardium and lymph nodes was assessed by 18 F-fluorideoxyglucose positron emission tomography/computed tomography. During a median follow-up period of 2.96 (IQR 2.24-4.27) years, the primary outcome occurred in 24 patients (29%). Higher serum sIL-2R levels (>538 U/mL, the median) were significantly related to increased incidence of primary outcome (P = 0.037). Multivariable Cox regression analysis showed that a higher sIL-2R was independently associated with an increased subsequent risk of adverse events (HR 3.71, 95% CI 1.63-8.44, P = 0.002), even after adjustment for significant covariates. sIL-2R levels were significantly correlated to inflammatory activity in lymph nodes (r = 0.346, P = 0.003) but not the myocardium (r = 0.131, P = 0.27). CONCLUSIONS: Increased sIL-2R is associated with worse long-term clinical outcomes accompanied by increased systemic inflammatory activity in CS patients.
  • Development and validation of a prediction model based on the organ-based metabolic tumor volume on FDG-PET in patients with differentiated thyroid carcinoma.
    Yuko Uchiyama, Kenji Hirata, Shiro Watanabe, Shozo Okamoto, Tohru Shiga, Kazufumi Okada, Yoichi M Ito, Kohsuke Kudo
    Annals of nuclear medicine, 35, 11, 1223, 1231, 2021年08月11日, ［査読有り］, ［責任著者］, ［国内誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Although patients with differentiated thyroid cancer (DTC) generally have a good prognosis, patients with a large metabolic tumor volume (MTV) on FDG-PET may experience poor clinical courses. We measured organ-based MTVs and tested its prognostic performance in comparison to conventional MTV (cMTV). METHODS: We retrospectively analyzed the cases of 280 patients who received their first I-131 therapy in 2003-2014 at our hospital and showed an FDG-avid metastatic lesion. We randomly divided the patients into training (n = 190) and validation (n = 90) datasets. We classified the MTVs as MTVneck-node, MTVdistant-node, MTVlung, MTVbone, and MTVother-organs and tested with/without dichotomization vis-à-vis overall survival (OS). Based on the estimated weighting coefficients of the organ-based MTVs, we propose a new index: the adjusted whole-body MTV (aMTV). Using the validation dataset, we compared the aMTV with cMTV for predicting OS. RESULTS: In a univariate analysis, MTVdistant-node and MTVother-organs were more strongly correlated with the OS than the dichotomized forms, whereas the dichotomized forms of MTVneck-node, MTVlung, and MTVbone were more strongly correlated with OS than the continuous variables. The aMTV was thus expressed as 0.69 × dic(MTVneck-node) + 0.02 × MTVdistant-node + 1.05 × dic(MTVlung) + 1.58 × dic(MTVbone) + 0.01 × MTVother-organs, where dic(x) represents 0 or 1 based on the optimized cut-off. In the model evaluation using the validation group, aMTV was a significant predictor of OS with a higher c-index (0.7676) than cMTV (0.7218). CONCLUSION: In DTC patients with FDG-avid metastasis before I-131 therapy, all organ-based MTVs were significant predictors of prognosis. As the aMTV outperformed the cMTV for predicting prognoses, we recommend measuring the MTV on an organ basis.
  • Prediction of the local treatment outcome in patients with oropharyngeal squamous cell carcinoma using deep learning analysis of pretreatment FDG-PET images.
    Noriyuki Fujima, V Carlota Andreu-Arasa, Sara K Meibom, Gustavo A Mercier, Minh Tam Truong, Kenji Hirata, Koichi Yasuda, Satoshi Kano, Akihiro Homma, Kohsuke Kudo, Osamu Sakai
    BMC cancer, 21, 1, 900, 900, 2021年08月06日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: This study aimed to assess the utility of deep learning analysis using pretreatment FDG-PET images to predict local treatment outcome in oropharyngeal squamous cell carcinoma (OPSCC) patients. METHODS: One hundred fifty-four OPSCC patients who received pretreatment FDG-PET were included and divided into training (n = 102) and test (n = 52) sets. The diagnosis of local failure and local progression-free survival (PFS) rates were obtained from patient medical records. In deep learning analyses, axial and coronal images were assessed by three different architectures (AlexNet, GoogLeNET, and ResNet). In the training set, FDG-PET images were analyzed after the data augmentation process for the diagnostic model creation. A multivariate clinical model was also created using a binomial logistic regression model from a patient's clinical characteristics. The test data set was subsequently analyzed for confirmation of diagnostic accuracy. Assessment of local PFS rates was also performed. RESULTS: Training sessions were successfully performed with an accuracy of 74-89%. ROC curve analyses revealed an AUC of 0.61-0.85 by the deep learning model in the test set, whereas it was 0.62 by T-stage, 0.59 by clinical stage, and 0.74 by a multivariate clinical model. The highest AUC (0.85) was obtained with deep learning analysis of ResNet architecture. Cox proportional hazards regression analysis revealed deep learning-based classification by a multivariate clinical model (P < .05), and ResNet (P < .001) was a significant predictor of the treatment outcome. In the Kaplan-Meier analysis, the deep learning-based classification divided the patient's local PFS rate better than the T-stage, clinical stage, and a multivariate clinical model. CONCLUSIONS: Deep learning-based diagnostic model with FDG-PET images indicated its possibility to predict local treatment outcomes in OPSCCs.
  • Extremely low 18F-fluorodeoxyglucose uptake in the brain of a patient with metastatic neuroblastoma and its recovery after chemotherapy: A case report.
    Yutaka Hoshino, Minako Sugiyama, Kenji Hirata, Shohei Honda, Hitoshi Saito, Atsushi Manabe, Kohsuke Kudo
    Acta radiologica open, 10, 7, 20584601211026810, 20584601211026810, 2021年07月, ［査読有り］, ［責任著者］, ［国際誌］
    英語, Commonly, physiological 18F-fluorodeoxyglucose (FDG) uptake in the brain can be observed in 18F-FDG positron emission tomography. Abnormal uptake of 18F-FDG in the brain suggests disorders of central nervous system. Here, we present a case of extremely low 18F-FDG uptake in the brain of a 4-year-old girl with whole-body metastatic neuroblastoma. Almost missing of physiological 18F-FDG uptake in the brain was ascribed at least partly to the metastatic neuroblastoma. The brain could regain physiological 18F-FDG uptake after chemotherapy.
  • 99mTc-GSA Scintigraphy Could Predict Post-Hepatectomy Liver Failure-Related Death in Biliary Surgery.
    Takehiro Noji, Ayano Inoue, Yoshitsugu Nakanishi, Takahiro Tsuchikawa, Keisuke Okamura, Kenji Hirata, Satoshi Hirano
    Journal of gastrointestinal surgery : official journal of the Society for Surgery of the Alimentary Tract, 25, 12, 3236, 3238, 2021年06月25日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）
  • Optimal relaxation parameters of dynamic row-action maximum likelihood algorithm and post-smoothing filter for image reconstruction of dedicated breast PET.
    Yoko Satoh, Masamichi Imai, Kenji Hirata, Yuzo Asakawa, Chihiro Ikegawa, Hiroshi Onishi
    Annals of nuclear medicine, 35, 5, 608, 616, 2021年03月27日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: This study aimed to determine the optimal β value of the relaxation control parameter and the post-smoothing filter in the list-mode dynamic row-action maximum likelihood algorithm (LM-DRAMA) to detect early stage breast cancer with high-resolution dedicated breast positron emission tomography (dbPET) in phantom and clinical studies. METHODS: A breast phantom containing four spheres (5, 7.5, 10, and 16 mm in diameter) was filled with 18F-fluorodeoxyglucose solution (sphere-to-background ratio, 8:1) and scanned on a dbPET scanner. The images were reconstructed using LM-DRAMA with different β values (5, 20, or 100) and Gaussian post-filters (0, 0.78, 1.17, 1.56, 1.95, or 2.34 mm). Other conditions were according to those routinely used (1 iteration and 128 subsets including attenuation and scatter correction). Image quality was evaluated visually and by computing the coefficient of variation of the background (CVBG), detectability index (DI), and contrast recovery coefficient. Parameters optimized in these phantom studies were applied to 25 clinical data sets. Variabilities for different reconstruction methods in visual scores, the maximum standardized uptake value of breast cancer, and the tumor-to-background uptake ratio were estimated. RESULTS: The reconstruction images of the phantom with higher β values and smaller post-filters yielded higher visual scores for detectability and DI and lower smoothness and CVBG scores. Based on the phantom study, the β values and post-filter were optimized for clinical dbPET images except for β5 and 2.34 mm post-filter. Applying the other reconstructions to clinical studies showed that β100 provided higher quantitative parameter values. The detectability of lesions was similar for β100 and β20 and decreased with larger post-filters. The lesion detection rate was similar for β100 and β20 and decreased with larger post-filter. CONCLUSION: The relaxation coefficient factor β20 and a 0.78- or 1.17-mm post-filter were optimal for dbPET image reconstruction with balanced spatial resolution and noise. However, they should be selected according to the impact on the dbPET image and the purpose of the examination.
  • Quantitative FDG PET Assessment for Oncology Therapy.
    Kenji Hirata, Nagara Tamaki
    Cancers, 13, 4, 2021年02月19日, ［査読有り］, ［筆頭著者］, ［国際誌］
    英語, 研究論文（学術雑誌）, Positron emission tomography (PET) has unique characteristics for quantitative assessment of tumour biology in vivo. Accumulation of F-18 fluorodeoxyglucose (FDG) may reflect tumour characteristics based on its metabolic activity. Quantitative assessment of FDG uptake can often be applied for treatment monitoring after chemotherapy or chemoradiotherapy. Numerous studies indicated biochemical change assessed by FDG PET as a more sensitive marker than morphological change estimated by CT or MRI. In addition, those with complete metabolic response after therapy may show better disease-free survival and overall survival than those with other responses. Assessment of metabolic change may be performed using absolute FDG uptake in the tumour (standardized uptake value: SUV). In addition, volumetric parameters such as metabolic tumour volume (MTV) have been introduced for quantitative assessment of FDG uptake in tumour. More recently, radiomics approaches that focus on image-based precision medicine have been applied to FDG PET, as well as other radiological imaging. Among these, texture analysis extracts intratumoral heterogeneity on a voxel-by-voxel basis. Combined with various machine learning techniques, these new quantitative parameters hold a promise for assessing tissue characterization and predicting treatment effect, and could also be used for future prognosis of various tumours, although multicentre clinical trials are needed before application in clinical settings.
  • Preoperative Texture Analysis Using 11C-Methionine Positron Emission Tomography Predicts Survival after Surgery for Glioma.
    Osamu Manabe, Shigeru Yamaguchi, Kenji Hirata, Kentaro Kobayashi, Hiroyuki Kobayashi, Shunsuke Terasaka, Takuya Toyonaga, Keiichi Magota, Yuji Kuge, Nagara Tamaki, Tohru Shiga, Kohsuke Kudo
    Diagnostics (Basel, Switzerland), 11, 2, 2021年01月28日, ［査読有り］, ［責任著者］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Positron emission tomography with 11C-methionine (MET) is well established in the diagnostic work-up of malignant brain tumors. Texture analysis is a novel technique for extracting information regarding relationships among surrounding voxels, in order to quantify their inhomogeneity. This study evaluated whether the texture analysis of MET uptake has prognostic value for patients with glioma. METHODS: We retrospectively analyzed adults with glioma who had undergone preoperative metabolic imaging at a single center. Tumors were delineated using a threshold of 1.3-fold of the mean standardized uptake value for the contralateral cortex, and then processed to calculate the texture features in glioma. RESULTS: The study included 42 patients (median age: 56 years). The World Health Organization classifications were grade II (7 patients), grade III (17 patients), and grade IV (18 patients). Sixteen (16.1%) all-cause deaths were recorded during the median follow-up of 18.8 months. The univariate analyses revealed that overall survival (OS) was associated with age (hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01-1.08, p = 0.0093), tumor grade (HR 3.64, 95% CI 1.63-9.63, p = 0.0010), genetic status (p < 0.0001), low gray-level run emphasis (LGRE, calculated from the gray-level run-length matrix) (HR 2.30 × 1011, 95% CI 737.11-4.23 × 1019, p = 0.0096), and correlation (calculated from the gray-level co-occurrence matrix) (HR 5.17, 95% CI 1.07-20.93, p = 0.041). The multivariate analyses revealed OS was independently associated with LGRE and correlation. The survival curves were also significantly different (both log-rank p < 0.05). CONCLUSION: Textural features obtained using preoperative MET positron emission tomography may compliment the semi-quantitative assessment for prognostication in glioma cases.
  • Preliminary study of AI-assisted diagnosis using FDG-PET/CT for axillary lymph node metastasis in patients with breast cancer.
    Zongyao Li, Kazuhiro Kitajima, Kenji Hirata, Ren Togo, Junki Takenaka, Yasuo Miyoshi, Kohsuke Kudo, Takahiro Ogawa, Miki Haseyama
    EJNMMI research, 11, 1, 10, 10, 2021年01月25日, ［査読有り］, ［責任著者］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: To improve the diagnostic accuracy of axillary lymph node (LN) metastasis in breast cancer patients using 2-[18F]FDG-PET/CT, we constructed an artificial intelligence (AI)-assisted diagnosis system that uses deep-learning technologies. MATERIALS AND METHODS: Two clinicians and the new AI system retrospectively analyzed and diagnosed 414 axillae of 407 patients with biopsy-proven breast cancer who had undergone 2-[18F]FDG-PET/CT before a mastectomy or breast-conserving surgery with a sentinel lymph node (LN) biopsy and/or axillary LN dissection. We designed and trained a deep 3D convolutional neural network (CNN) as the AI model. The diagnoses from the clinicians were blended with the diagnoses from the AI model to improve the diagnostic accuracy. RESULTS: Although the AI model did not outperform the clinicians, the diagnostic accuracies of the clinicians were considerably improved by collaborating with the AI model: the two clinicians' sensitivities of 59.8% and 57.4% increased to 68.6% and 64.2%, respectively, whereas the clinicians' specificities of 99.0% and 99.5% remained unchanged. CONCLUSIONS: It is expected that AI using deep-learning technologies will be useful in diagnosing axillary LN metastasis using 2-[18F]FDG-PET/CT. Even if the diagnostic performance of AI is not better than that of clinicians, taking AI diagnoses into consideration may positively impact the overall diagnostic accuracy.
  • Texture analysis of delayed contrast-enhanced computed tomography to diagnose cardiac sarcoidosis.
    Satonori Tsuneta, Noriko Oyama-Manabe, Kenji Hirata, Taisuke Harada, Tadao Aikawa, Osamu Manabe, Hiroshi Ohira, Kazuhiro Koyanagawa, Masanao Naya, Kohsuke Kudo
    Japanese journal of radiology, 39, 5, 442, 450, 2021年01月22日, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, PURPOSE: To investigate the diagnostic value of texture analysis to differentiate cardiac sarcoidosis (CS) from other non-ischemic cardiomyopathies (non-CS). MATERIALS AND METHODS: Twenty CS patients and 15 non-CS patients who had undergone myocardial CT delayed enhancement (CTDE) were included. A total of 36 texture features were calculated according to the CT attenuation of CTDE. We investigated the diagnostic value to differentiate CS from non-CS. We also assessed the intra- and inter-rater reproducibility for each feature and inter-observer agreement for visual assessment. RESULTS: Seven extracted features had significantly higher run length non-uniformity (RLNU) values (5.4 × 102 ± 6.2 × 102 vs. 11.2 × 102 ± 4.9 × 102, p = 0.037) and significantly lower low gray-level zone emphasis (LGZE) values (7.1 × 10-3 ± 8.6 × 10-3 vs. 18.1 × 10-3 ± 16.9 × 10-3, p = 0.017) in CS than in non-CS. Intra- and inter-rater reproducibility of RLNU and LGZE were excellent (ICCs > 0.8), while inter-observer agreement of visual assessment was poor (kappa = 0.19). The accuracies of texture analysis were 69% with RLNU and 71% with LGZE, which were better than that of visual assessment. CONCLUSION: Texture analysis of CTDE could differentiate CS from non-CS with high reproducibility.
  • A Preliminary Study to Use SUVmax of FDG PET-CT as an Identifier of Lesion for Artificial Intelligence.
    Kenji Hirata, Osamu Manabe, Keiichi Magota, Sho Furuya, Tohru Shiga, Kohsuke Kudo
    Frontiers in medicine, 8, 647562, 647562, 2021年, ［査読有り］, ［筆頭著者］, ［国際誌］
    英語, 研究論文（学術雑誌）, Background: Diagnostic reports contribute not only to the particular patient, but also to constructing massive training dataset in the era of artificial intelligence (AI). The maximum standardized uptake value (SUVmax) is often described in daily diagnostic reports of [18F] fluorodeoxyglucose (FDG) positron emission tomography (PET) - computed tomography (CT). If SUVmax can be used as an identifier of lesion, that would greatly help AI interpret diagnostic reports. We aimed to clarify whether the lesion can be localized using SUVmax strings. Methods: The institutional review board approved this retrospective study. We investigated a total of 112 lesions from 30 FDG PET-CT images acquired with 3 different scanners. SUVmax was calculated from DICOM files based on the latest Quantitative Imaging Biomarkers Alliance (QIBA) publication. The voxels showing the given SUVmax were exhaustively searched in the whole-body images and counted. SUVmax was provided with 5 different degrees of precision: integer (e.g., 3), 1st decimal places (DP) (3.1), 2nd DP (3.14), 3rd DP (3.142), and 4th DP (3.1416). For instance, when SUVmax = 3.14 was given, the voxels with 3.135 ≤ SUVmax < 3.145 were extracted. We also evaluated whether local maximum restriction could improve the identifying performance, where only the voxels showing the highest intensity within some neighborhood were considered. We defined that "identical detection" was achieved when only single voxel satisfied the criterion. Results: A total of 112 lesions from 30 FDG PET-CT images were investigated. SUVmax ranged from 1.3 to 49.1 (median = 5.6). Generally, when larger and more precise SUVmax values were given, fewer voxels satisfied the criterion. The local maximum restriction was very effective. When SUVmax was determined to 4 decimal places (e.g., 3.1416) and the local maximum restriction was applied, identical detection was achieved in 33.3% (lesions with SUVmax < 2), 79.5% (2 ≤ SUVmax < 5), and 97.8% (5 ≤ SUVmax) of lesions. Conclusion: In this preliminary study, SUVmax of FDG PET-CT could be used as an identifier to localize the lesion if precise SUVmax is provided and local maximum restriction was applied, although the lesions showing SUVmax < 2 were difficult to identify. The proposed method may have potential to make use of diagnostic reports retrospectively for constructing training datasets for AI.
  • Herpes zoster infection mimicking pelvic lymph node metastasis on FDG-PET/CT in a patient with cervical cancer.
    Kazutaka Harashima, Shiro Watanabe, Nanase Okazaki, Daisuke Endo, Yuko Uchiyama, Fumi Kato, Kenji Hirata, Kohsuke Kudo
    Asia Oceania journal of nuclear medicine & biology, 9, 2, 183, 187, 2021年, ［査読有り］, ［国際誌］
    英語, Although 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is an established method for the staging of malignancies, benign lesions (e.g, active inflammatory lesions) often show increased metabolic activity. Herpes zoster is the clinical manifestation of the activation and replication of dormant varicella-zoster virus (VZV) in individuals with decreased cell-mediated immunity. Although the diagnosis of herpes zoster is clinical, it is sometimes observed incidentally during imaging for another disease. We describe the case of a 67-year-old Japanese female patient diagnosed with cervical cancer in whom FDG-PET/CT revealed herpes zoster manifestations: hypermetabolic cutaneous lesions in the buttock and pelvic lymph node involvement. The resected lymph nodes showed no malignant lesions but revealed lymphoid follicle formation, probably related to viral infection. There has been no report comparing FDG-PET findings of lymph nodes with histologic findings; the present findings are compatible with a clinically VZV-induced inflammatory reaction in regional lymph nodes, which increased FDG accumulation. Active infection with VZV displays increased FDG uptake in regional lymph nodes and may lead to incorrect malignant disease management in oncology. Misdiagnoses can be avoided by a careful interpretation by experienced nuclear medicine physicians as well as proper clinical evaluation.
  • Halo artifacts of indwelling urinary catheter by inaccurate scatter correction in 18F-FDG PET/CT imaging: incidence, mechanism, and solutions.
    Keiichi Magota, Naoto Numata, Daiki Shinyama, Junya Katahata, Yamato Munakata, Piotr J Maniawski, Kentaro Kobayashi, Osamu Manabe, Kenji Hirata, Ukihide Tateishi, Kohsuke Kudo, Tohru Shiga
    EJNMMI physics, 7, 1, 66, 66, 2020年11月13日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Halo artifacts from urinary catheters can occur due to inaccurate scatter correction, and the artifacts affect the tumor visibility in 18F-FDG PET/CT images. We investigated the incidence rate and the mechanisms of halo-artifact generation and explored several scatter correction techniques to prevent artifacts. METHODS: We conducted patient and phantom studies. (1) We retrospectively reviewed the cases of patients who had undergone 18F-FDG PET/CT scans. To determine the frequency of halo-artifact generation, we used the patients' PET images with a standard scatter correction based on a tail-fitted single-scatter simulation (TF-SSS) using 4-mm voxel μ-maps (TFS 4-mm). (2) We performed phantom studies to evaluate the effects of a urine catheter and two scatter correction techniques, i.e., TF-SSS with 2-mm voxel μ-maps (TFS 2-mm) and a Monte Carlo-based single-scatter simulation (MC-SSS) using 4-mm voxel μ-maps (MCS 4-mm). The average standardized uptake values (SUVs) were measured for axial PET images. (3) Using the patients' data, we investigated whether TFS 2-mm and MCS 4-mm can eliminate the artifacts in the clinical images. RESULTS: (1) There were 61 patients with urinary catheters; in five (8.2%), halo artifacts were observed in the TFS 4-mm PET images. (2) The phantom study clearly reproduced the halo artifacts in the TFS 4-mm PET images. The halo artifacts were generated when urine moved in the interval between the CT and PET imaging, and when the urinary catheter was placed in a circular shape. The SUVs for the TFS 4-mm and TFS-2mm PET images were underestimated at the halo-artifact regions, whereas the SUVs for the MCS 4-mm PET images were close to the true values. (3) The halo artifacts disappeared in the TFS 2-mm PET images in 4/5 patients but not 1/5 patient, whereas the halo artifacts were completely absent in the MCS 4-mm PET images in 5/5 patients. CONCLUSIONS: These data suggest that halo artifacts are caused if the PET images do not correspond to the physical material in the μ-maps, which induces the scatter correction error. With the MC-SSS, it was possible to accurately estimate the scatter without generating halo artifacts.
  • Quantitative bone single photon emission computed tomography analysis of the effects of duration of bisphosphonate administration on the parietal bone.
    Hironobu Hata, Tomoka Kitao, Jun Sato, Takuya Asaka, Kenji Imamachi, Masaaki Miyakoshi, Kenji Hirata, Keiichi Magota, Yamato Munakata, Tohru Shiga, Yutaka Yamazaki, Yoshimasa Kitagawa
    Scientific reports, 10, 1, 17461, 17461, 2020年10月15日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Effects of long-term bisphosphonate (BP) administration on the metabolism of healthy bone and the concomitant changes in imaging are unclear. Hence, we aimed to retrospectively investigate the effects of long-term BP administration on the intact parietal bone using the standardised uptake value (SUV) derived from single photon emission computed tomography (SPECT). We enrolled 29 patients who had odontogenic infection, osteoporosis, bone metastasis cancer, or rheumatoid arthritis, and classified them into BP-naïve: A (14 patients) and BP-treated: B, < 4 years (7 patients) and C, ≥ 4 years (8 patients) groups. We measured the maximum bilateral SUV (SUVmax) of the parietal bone using quantitative bone SPECT software. There were significant differences in the duration of BP administration and SUVmax of the parietal bone among the diseases (P < 0.0001 and P = 0.0086, respectively). There was a positive correlation between the duration of BP administration and SUVmax of the parietal bone (rs = 0.65, P = 0.0002). The SUVmax was significantly different between A and B (P = 0.02) and between A and C (P = 0.0024) groups. This is the first report on the correlation between long-term BP administration and the SUVmax of the parietal bone using the quantitative bone SPECT analysis.
  • 食道癌の術前化学療法に対するFDG-PET/CTの有用性 多施設共同研究　　　　　　　　　　　　　　　
    甲斐田 勇人, 北島 一宏, 中條 正豊, 石橋 愛, 南本 亮吾, 平田 健司, 中谷 航也, Ao Hung, 服部 聡, 安田 卓司, 石井 一成
    核医学, 57, Suppl., S144, S144, (一社)日本核医学会, 2020年10月
    日本語
  • 【Q&Aでまとめる! 予後予測・治療効果予測の画像検査】胸部(呼吸器・循環器・乳腺) 心臓サルコイドーシス疑い患者の予後を予測する画像検査法は何か?
    真鍋 治, 小梁川 和宏, 納谷 昌直, 相川 忠夫, 平田 健司, 小林 健太郎, 古家 翔, 真鍋 徳子, 立石 宇貴秀
    臨床放射線, 65, 8, 825, 830, 金原出版(株), 2020年08月
    日本語
  • Biodistribution and internal radiation dosimetry of a novel probe for thymidine phosphorylase imaging, [123I]IIMU, in healthy volunteers.
    Shiro Watanabe, Ken-Ichi Nishijima, Shozo Okamoto, Keiichi Magota, Kenji Hirata, Takuya Toyonaga, Tohru Shiga, Yuji Kuge, Nagara Tamaki
    Annals of nuclear medicine, 34, 8, 595, 599, 2020年08月, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: We evaluated the radiation dosage, biodistribution, human safety, and tolerability of the injection of a single dose of [123I] 5-iodo-6-[ (2-iminoimidazolidinyl)methyl]uracil (IIMU), a new radiotracer targeting thymidine phosphorylase (TP), in healthy volunteers. METHODS: Potential participants were tested at our hospital to confirm their eligibility. Two healthy male adults passed the screening tests. They were injected with 56 and 111 MBq of [123I]IIMU, respectively. Safety assessments were performed before and at 1, 3, 6, 9, 24, 48 h, and 1-week post-injection. Whole-body emission scans were conducted at 1, 3, 6, 24, and 48 h post-injection. Regions of interest were manually drawn to enclose the entire body at each time point, identifying high-uptake organs to obtain the time-activity curves. Urine and blood samples were collected at 1, 2, 3, 4, 5, 6, 9, 24, and 48 h post-injection. The radiation dose for each organ and the effective doses were estimated using OLINDA/EXM 1.1 software. RESULTS: No adverse events were observed as of the follow-up visit > 1-week post-injection. In both subjects, the highest uptake of [123I]IIMU occurred in the liver, with peak injected activity (%IA) values of 17.7% and 15.1%, respectively. The second highest uptake was in the thyroid (0.35% and 0.66% IA). The %IA decreased gradually toward the end of the study (48 h) in all organs except the liver and thyroid. By the end of the study, 52.5% and 51.5% of the injected activity of [123I]IIMU had been excreted via the subjects' renal systems. The estimated mean effective doses of [123I]IIMU were 9.19 μSv/MBq and 10.1 μSv/MBq, respectively. CONCLUSION: In this preliminary study, [123I]IIMU was safely administered to healthy adults, and its potential clinical use in TP imaging was revealed.
  • Monitoring indices of bone inflammatory activity of the jaw using SPECT bone scintigraphy: a study of ARONJ patients.
    Hironobu Hata, Tomoka Kitao, Jun Sato, Takuya Asaka, Noritaka Ohga, Kenji Imamachi, Kenji Hirata, Tohru Shiga, Yutaka Yamazaki, Yoshimasa Kitagawa
    Scientific reports, 10, 1, 11385, 11385, 2020年07月09日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Development of quantitative analysis software has enabled application of several standardised uptake values (SUV) for bone analysis in single photon emission computed tomography (SPECT). The present retrospective study aimed to develop a reliable method of monitoring bone inflammatory activity in antiresorptive agent-related osteonecrosis of the jaw (ARONJ) using SPECT quantitative analysis software. Fifteen ARONJ patients underwent SPECT before and after anti-inflammatory therapy. We calculated the mean maximum SUV (SUVmax) of the bilateral cranial bones using quantitative analysis software and used this as the control [C]. We attempted to adjust the SUVmax of the lesion [L] as follows: adjusted SUVmax (aSUVmax) = [L] - [C]. The optimum threshold to calculate the metabolic bone volume (MBV) (cm3) was [C] + 3. The threshold values obtained for each case were input to calculate MBV at each osteomyelitis site. Retrospectively, we compared aSUVmax and MBV of each patient's ARONJ before and after anti-inflammatory therapy. The patients' high aSUVmax or large MBV of the ARONJ reduced rapidly, reflecting individual clinical findings after treatment. Application of SPECT quantitative analysis software to monitor bone inflammatory activity in ARONJ could improve the prognosis-deciding abilities of clinicians and enable them to treat ARONJ effectively.
  • High metabolic heterogeneity on baseline 18FDG-PET/CT scan as a poor prognostic factor for newly diagnosed diffuse large B-cell lymphoma.
    Hajime Senjo, Kenji Hirata, Koh Izumiyama, Koichiro Minauchi, Eriko Tsukamoto, Kazuo Itoh, Minoru Kanaya, Akio Mori, Shuichi Ota, Daigo Hashimoto, Takanori Teshima
    Blood advances, 4, 10, 2286, 2296, 2020年05月26日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Metabolic heterogeneity (MH) can be measured using 18F-fluorodeoxyglucose (18FDG) positron emission tomography/computed tomography (PET/CT), and it indicates an inhomogeneous tumor microenvironment. High MH has been shown to predict a worse prognosis for primary mediastinal B-cell lymphoma, whereas its prognostic value in diffuse large B-cell lymphoma (DLBCL) remains to be determined. In the current study, we investigated the prognostic values of MH evaluated in newly diagnosed DLBCL. In the training cohort, 86 patients treated with cyclophosphamide, doxorubicin, vincristine, and prednisone-like chemotherapies were divided into low-MH and high-MH groups using receiver operating characteristic analysis. MH was not correlated with metabolic tumor volume of the corresponding lesion, indicating that MH was independent of tumor burden. At 5 years, overall survivals were 89.5% vs 61.2% (P = .0122) and event-free survivals were 73.1% vs 51.1% (P = .0327) in the low- and high-MH groups, respectively. A multivariate Cox-regression analysis showed that MH was an independent predictive factor for overall survival. The adverse prognostic impacts of high MH were confirmed in an independent validation cohort with 64 patients. In conclusion, MH on baseline 18FDG-PET/CT scan predicts treatment outcomes for patients with newly diagnosed DLBCL.
  • Evaluation of non-Gaussian model-based diffusion-weighted imaging in oral squamous cell carcinoma: comparison with tumour functional information derived from positron-emission tomography.
    T Shima, N Fujima, S Yamano, K Kudo, K Hirata, K Minowa
    Clinical radiology, 75, 5, 397.e15-397.e21, 2020年05月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, AIM: To evaluate and compare diffusion-weighted imaging (DWI) parameters derived from a non-Gaussian fitting model and positron-emission tomography (PET) parameters derived from 18F-fluoromisonidazole-PET (FMISO-PET) in patients with oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: Primary sites were evaluated prospectively in 18 patients. DWI was performed using six b-values (0-2,500). Diffusion-related parameters of kurtosis value (K), the kurtosis-corrected diffusion coefficient (DK), diffusion heterogeneity (α), distributed diffusion coefficient (DDC), the slow diffusion coefficient (Dslow), and the apparent diffusion coefficient (ADC) were calculated from four diffusion-fitting models. Maximal standardised uptake values (SUVmax), mean standardised uptake values (SUVmean), and the tumour-to-muscle ration (TMR) of the SUV value were calculated for FMISO-PET. Spearman's correlation coefficient was used to evaluate the correlation between each non-Gaussian diffusion model parameters and PET parameter. RESULTS: There was moderate correlation between FMISO-PET SUVmax and Dslow (ρ=-0.45, p=0.06). In addition, there was good correlation between TMRmax and five non-Gaussian diffusion model parameters (K: ρ=0.65, p=0.004, DK: ρ=-0.72, p=0.0008, DDC: ρ=-0.75, p=0.0003, ADC: ρ=-0.74, p=0.0005, and Dslow: ρ= -0.65, p=0.003), and between TMRmean and five non-Gaussian model parameters (K: ρ=0.64, p=0.005, DK: ρ=-0.61, p=0.007, DDC: ρ=-0.63, p=0.005, ADC: ρ=-0.61, p=0.007, and Dslow: ρ=-0.56, p=0.015). CONCLUSION: Non-Gaussian diffusion model parameters can be related to tumour hypoxia.
  • Prognostic Value of 18F-FDG PET Using Texture Analysis in Cardiac Sarcoidosis.
    Osamu Manabe, Kazuhiro Koyanagawa, Kenji Hirata, Noriko Oyama-Manabe, Hiroshi Ohira, Tadao Aikawa, Sho Furuya, Masanao Naya, Ichizo Tsujino, Yuuki Tomiyama, Yuka Otaki, Toshihisa Anzai, Nagara Tamaki
    JACC. Cardiovascular imaging, 13, 4, 1096, 1097, 2020年04月, ［査読有り］, ［国際誌］
    英語
  • A convolutional neural network-based system to classify patients using FDG PET/CT examinations.
    Keisuke Kawauchi, Sho Furuya, Kenji Hirata, Chietsugu Katoh, Osamu Manabe, Kentaro Kobayashi, Shiro Watanabe, Tohru Shiga
    BMC cancer, 20, 1, 227, 227, 2020年03月17日, ［査読有り］, ［責任著者］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: As the number of PET/CT scanners increases and FDG PET/CT becomes a common imaging modality for oncology, the demands for automated detection systems on artificial intelligence (AI) to prevent human oversight and misdiagnosis are rapidly growing. We aimed to develop a convolutional neural network (CNN)-based system that can classify whole-body FDG PET as 1) benign, 2) malignant or 3) equivocal. METHODS: This retrospective study investigated 3485 sequential patients with malignant or suspected malignant disease, who underwent whole-body FDG PET/CT at our institute. All the cases were classified into the 3 categories by a nuclear medicine physician. A residual network (ResNet)-based CNN architecture was built for classifying patients into the 3 categories. In addition, we performed a region-based analysis of CNN (head-and-neck, chest, abdomen, and pelvic region). RESULTS: There were 1280 (37%), 1450 (42%), and 755 (22%) patients classified as benign, malignant and equivocal, respectively. In the patient-based analysis, CNN predicted benign, malignant and equivocal images with 99.4, 99.4, and 87.5% accuracy, respectively. In region-based analysis, the prediction was correct with the probability of 97.3% (head-and-neck), 96.6% (chest), 92.8% (abdomen) and 99.6% (pelvic region), respectively. CONCLUSION: The CNN-based system reliably classified FDG PET images into 3 categories, indicating that it could be helpful for physicians as a double-checking system to prevent oversight and misdiagnosis.
  • Probing Estrogen Sulfotransferase-Mediated Inflammation with [11C]-PiB in the Living Human Brain.
    Andrew J Surmak, Koon-Pong Wong, Graham B Cole, Kenji Hirata, Alexander A Aabedi, Omid Mirfendereski, Payam Mirfendereski, Amy S Yu, Sung-Cheng Huang, John M Ringman, David S Liebeskind, Jorge R Barrio
    Journal of Alzheimer's disease : JAD, 73, 3, 1023, 1033, 2020年, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: 2-(4'- [11C]Methylaminophenyl)-6-hydroxybenzothiazole ([11C]-PiB), purportedly a specific imaging agent for cerebral amyloid-β plaques, is a specific, high affinity substrate for estrogen sulfotransferase (SULT1E1), an enzyme that regulates estrogen homeostasis. OBJECTIVE: In this work, we use positron emission tomography (PET) imaging with [11C]-PiB to assess the functional activity of SULT1E1 in the brain of moyamoya disease patients. METHODS: Ten moyamoya subjects and five control patients were evaluated with [11C]-PiB PET and structural MRI scans. Additionally, a patient with relapsing-remitting multiple sclerosis (RRMS) received [11C]-PiB PET scans before and after steroidal and immunomodulatory therapy. Parametric PET images were established to assess SULT1E1 distribution in the inflamed brain tissue. RESULTS: Increased [11C]-PiB SRTM DVR in the thalamus, pons, corona radiata, and internal capsule of moyamoya cohort subjects was observed in comparison with controls (p ≤ 0.01). This was observed in patients without treatment, with collateralization, and also after radiation. The post-treatment [11C]-PiB PET scan in one RRMS patient also revealed substantially reduced subcortical brain inflammation. In validation studies, [11C]-PiB autoradiography signal in the peri-infarct area of the rat middle cerebral arterial occlusion stroke model was shown to correlate with SULT1E1 immunohistochemistry. CONCLUSION: Strong [11C]-PiB PET signal associated with intracranial inflammation in the moyamoya syndrome cohort and a single RRMS patient appears consistent with functional imaging of SULT1E1 activity in the human brain. This preliminary work offers substantial and direct evidence that significant [11C]-PiB PET focal signals can be obtained from the living human brain with intracranial inflammation, signals not attributable to amyloid-β plaques.
  • Texture Analysis in the Diagnosis of Primary Breast Cancer: Comparison of High-Resolution Dedicated Breast Positron Emission Tomography (dbPET) and Whole-Body PET/CT.
    Yoko Satoh, Kenji Hirata, Daiki Tamada, Satoshi Funayama, Hiroshi Onishi
    Frontiers in medicine, 7, 603303, 603303, 2020年, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Objective: This retrospective study aimed to compare the ability to classify tumor characteristics of breast cancer (BC) of positron emission tomography (PET)-derived texture features between dedicated breast PET (dbPET) and whole-body PET/computed tomography (CT). Methods: Forty-four BCs scanned by both high-resolution ring-shaped dbPET and whole-body PET/CT were analyzed. The primary BC was extracted with a standardized uptake value (SUV) threshold segmentation method. On both dbPET and PET/CT images, 38 texture features were computed; their ability to classify tumor characteristics such as tumor (T)-category, lymph node (N)-category, molecular subtype, and Ki67 levels was compared. The texture features were evaluated using univariate and multivariate analyses following principal component analysis (PCA). AUC values were used to evaluate the diagnostic power of the computed texture features to classify BC characteristics. Results: Some texture features of dbPET and PET/CT were different between Tis-1 and T2-4 and between Luminal A and other groups, respectively. No association with texture features was found in the N-category or Ki67 level. In contrast, receiver-operating characteristic analysis using texture features' principal components showed that the AUC for classification of any BC characteristics were equally good for both dbPET and whole-body PET/CT. Conclusions: PET-based texture analysis of dbPET and whole-body PET/CT may have equally good classification power for BC.
  • Development of Combination Methods for Detecting Malignant Uptakes Based on Physiological Uptake Detection Using Object Detection With PET-CT MIP Images.
    Masashi Kawakami, Kenji Hirata, Sho Furuya, Kentaro Kobayashi, Hiroyuki Sugimori, Keiichi Magota, Chietsugu Katoh
    Frontiers in medicine, 7, 616746, 616746, 2020年, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Deep learning technology is now used for medical imaging. YOLOv2 is an object detection model using deep learning. Here, we applied YOLOv2 to FDG-PET images to detect the physiological uptake on the images. We also investigated the detection precision of abnormal uptake by a combined technique with YOLOv2. Using 3,500 maximum intensity projection (MIP) images of 500 cases of whole-body FDG-PET examinations, we manually drew rectangular regions of interest with the size of each physiological uptake to create a dataset. Using YOLOv2, we performed image training as transfer learning by initial weight. We evaluated YOLOv2's physiological uptake detection by determining the intersection over union (IoU), average precision (AP), mean average precision (mAP), and frames per second (FPS). We also developed a combination method for detecting abnormal uptake by subtracting the YOLOv2-detected physiological uptake. We calculated the coverage rate, false-positive rate, and false-negative rate by comparing the combination method-generated color map with the abnormal findings identified by experienced radiologists. The APs for physiological uptakes were: brain, 0.993; liver, 0.913; and bladder, 0.879. The mAP was 0.831 for all classes with the IoU threshold value 0.5. Each subset's average FPS was 31.60 ± 4.66. The combination method's coverage rate, false-positive rate, and false-negative rate for detecting abnormal uptake were 0.9205 ± 0.0312, 0.3704 ± 0.0213, and 0.1000 ± 0.0774, respectively. The physiological uptake of FDG-PET on MIP images was quickly and precisely detected using YOLOv2. The combination method, which can be utilized the characteristics of the detector by YOLOv2, detected the radiologist-identified abnormalities with a high coverage rate. The detectability and fast response would thus be useful as a diagnostic tool.
  • 18F-FMISO PET/CT detects hypoxic lesions of cardiac and extra-cardiac involvement in patients with sarcoidosis.
    Sho Furuya, Masanao Naya, Osamu Manabe, Kenji Hirata, Hiroshi Ohira, Tadao Aikawa, Kazuhiro Koyanagawa, Keiichi Magota, Ichizo Tsujino, Toshihisa Anzai, Yuji Kuge, Noriko Oyama-Manabe, Kohsuke Kudo, Tohru Shiga, Nagara Tamaki
    Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology, 28, 5, 2141, 2148, 2019年12月09日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: 18F-fluoromisonidazole (FMISO) is a hypoxia positron emission tomography (PET) tracer. Here, we evaluated cardiac and extra-cardiac sarcoidosis using both FMISO and 18F-fluorodeoxyglucose (FDG) PET/CT in a prospective cohort of patients with sarcoidosis. METHODS: Ten consecutive sarcoidosis patients with suspected cardiac involvement were prospectively enrolled. Each patient fasted overnight (for ≥ 18 hours) preceded by a low-carbohydrate diet before FDG PET/CT but not given special dietary instructions before the FMISO PET/CT scan. We visually and semiquantitatively assessed the uptakes of FMISO and FDG using the maximal standardized uptake value (SUVmax). The metabolic volume (MV) of FDG was calculated as the volume within the boundary determined by the threshold (mean SUV of blood pool × 1.5). RESULTS: Nine patients showed focal FDG uptake in the myocardium and were diagnosed with cardiac sarcoidosis. Among the patients with extra-cardiac lesions, FDG uptake was seen in 8 lymph nodes and 3 lung lesions. FMISO uptake was seen in the 7 cardiac (77.8%) and 6 extra-cardiac (54.5%) lesions. None of the patients showed physiological FMISO uptake in the myocardium. The SUVmax values of the lesions with FMISO uptake were higher than those of the lesions without FMISO uptake in both the cardiac (SUVmax: 9.9, IQR: 8.4-10.0 vs 7.3, IQR: 6.3-8.2) and non-cardiac lesions (SUVmax: 17.6, IQR: 14.5-19.3 vs 6.1, IQR: 5.9-6.2; P = 0.006). The MV values of the lesions with FMISO uptake were significantly higher than those of the lesions without FMISO uptake (111.3, IQR: 78.3-135.7 vs 6.4, IQR: 1.9-23.3; P = 0.0009). CONCLUSIONS: FMISO showed no physiological myocardial uptake and did not require special preparation. FMISO PET has the potential to detect hypoxic lesions in patients with sarcoidosis.
  • Combination of FDG-PET and FMISO-PET as a treatment strategy for patients undergoing early-stage NSCLC stereotactic radiotherapy.
    Shiro Watanabe, Tetsuya Inoue, Shozo Okamoto, Keiichi Magota, Ayumi Takayanagi, Jun Sakakibara-Konishi, Norio Katoh, Kenji Hirata, Osamu Manabe, Takuya Toyonaga, Yuji Kuge, Hiroki Shirato, Nagara Tamaki, Tohru Shiga
    EJNMMI research, 9, 1, 104, 104, 2019年12月04日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: We investigated the prognostic predictive value of the combination of fluorodeoxyglucose (FDG)- and fluoromisonidazole (FMISO)-PET in patients with non-small cell lung carcinoma (NSCLC) treated with stereotactic body radiation therapy (SBRT). PATIENTS AND METHODS: We prospectively examined patients with pathologically proven NSCLC; all underwent FDG and FMISO PET/CT scans before SBRT. PET images were acquired using a whole-body time-of-flight PET-CT scanner with respiratory gating. We classified them into recurrent and non-recurrent groups based on their clinical follow-ups and compared the groups' tumor diameters and PET parameters (i.e., maximum of the standardized uptake value (SUVmax), metabolic tumor volume, tumor-to-muscle ratio, and tumor-to-blood ratio). We performed univariate analysis to evaluate the impact of the PET variables on the patients' progression-free survival (PFS). We divided the patients by thresholds of FDG SUVmax and FMISO SUVmax obtained from receiver operating characteristic analysis for assessment of recurrence rate and PFS. RESULTS: Thirty-two NSCLC patients (19 male and 13 females; median age, 83 years) were enrolled. All received SBRT. At the study endpoint, 23 patients (71.9%) were non-recurrent and nine patients (28.1%) had recurrent disease. Significant between-group differences were observed in tumor diameter and all the PET parameters, demonstrating that those were significant predictors of the recurrence in all patients. In the 22 patients with tumors > 2 cm, tumor diameter and FDG SUVmax were not significant predictors. Thirty-two patients were divided into three patterns from the thresholds of FDG SUVmax (6.81) and FMISO SUVmax (1.89); A, low FDG and low FMISO (n = 14); B, high FDG and low FMISO (n = 8); C, high FDG and high FMISO (n = 10). No pattern A patient experienced tumor recurrence, whereas two pattern B patients (25%) and seven pattern C patients (70%) exhibited recurrence. A Kaplan-Meier analysis of all patients revealed a significant difference in PFS between patterns A and B (p = 0.013) and between patterns A and C (p < 0.001). In the tumors > 2 cm patients, significant differences in PFS were demonstrated between pattern A and C patients (p = 0.002). CONCLUSION: The combination of FDG- and FMISO-PET can identify patients with a baseline risk of recurrence and indicate whether additional therapy might be performed to improve survival.
  • Influence of the scan time point when assessing hypoxia in 18F-fluoromisonidazole PET: 2 vs. 4 h.
    Kentaro Kobayashi, Osamu Manabe, Kenji Hirata, Shigeru Yamaguchi, Hiroyuki Kobayashi, Shunsuke Terasaka, Takuya Toyonaga, Sho Furuya, Keiichi Magota, Yuji Kuge, Kohsuke Kudo, Tohru Shiga, Nagara Tamaki
    European journal of nuclear medicine and molecular imaging, 47, 8, 1833, 1842, 2019年11月28日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: 18F-fluoromisonidazole (18F-FMISO) is the most widely used positron emission tomography (PET) tracer for imaging tumor hypoxia. Previous reports suggested that the time from injection to the scan may affect the assessment of 18F-FMISO uptake. Herein, we directly compared the images at 2 h and 4 h after a single injection of 18F-FMISO. METHODS: Twenty-three patients with or suspected of having a brain tumor were scanned twice at 2 and 4 h following an intravenous injection of 18F-FMISO. We estimated the mean standardized uptake value (SUV) of the gray matter and white matter and the gray-to-white matter ratio in the background brain tissue from the two scans. We also performed a semi-quantitative analysis using the SUVmax and maximum tumor-to-normal ratio (TNR) for the tumor. RESULTS: At 2 h, the SUVmean of gray matter was significantly higher than that of white matter (median 1.23, interquartile range (IQR) 1.10-1.32 vs. 1.04, IQR 0.95-1.16, p < 0.0001), whereas at 4 h, it significantly decreased to approach that of the white matter (1.10, IQR 1.00-1.23 vs. 1.02, IQR 0.93-1.13, p = NS). The gray-to-white matter ratio thus significantly declined from 1.17 (IQR 1.14-1.19) to 1.09 (IQR 1.07-1.10) (p < 0.0001). All 7 patients with glioblastoma showed significant increases in the SUVmax (2.20, IQR 1.67-3.32 at 2 h vs. 2.65, IQR 1.74-4.41 at 4 h, p = 0.016) and the TNR (1.75, IQR 1.40-2.38 at 2 h vs. 2.34, IQR 1.67-3.60 at 4 h, p = 0.016). CONCLUSION: In the assessment of hypoxic tumors, 18F-FMISO PET for hypoxia imaging should be obtained at 4 h rather than 2 h after the injection.
  • Nuclear medicine practice in Japan: a report of the eighth nationwide survey in 2017
    Yoshihiro Nishiyama, Seigo Kinuya, Takashi Kato, Daiki Kayano, Shuhei Sato, Manabu Tashiro, Mitsuaki Tatsumi, Teisuke Hashimoto, Shingo Baba, Kenji Hirata, Mana Yoshimura, Hiroto Yoneyama
    Annals of Nuclear Medicine, 33, 10, 725, 732, Springer Science and Business Media LLC, 2019年10月, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: Subcommittee on Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to survey contemporary nuclear medicine practice and its changes over the years. METHODS: The subcommittee sent questionnaires, including the number and category of examinations as well as the kind and dose of the radiopharmaceuticals during the 30 days of June 2017, to all nuclear medicine institutes. The total numbers for the year 2017 were then estimated. RESULTS: A total of 1132 institutes responded to the survey, including 351 PET centers. The recovery rate was 90.6%. The number of gamma cameras installed was 1332 in total, with 7.0% decrease in 5 years. Dual-head cameras and hybrid SPECT/CT scanners accounted for 88.2 and 23.6%, respectively. The number of single-photon tracer studies in 2017 was 1.08 million which means a decrease in 5.7% in 5 years and 23.6% in 10 years. All but neurotransmitter system, sentinel lymph node, and liver scintigraphy decreased. Bone scintigraphy was a leading examination (32.3%), followed by myocardial scintigraphy (24.1%) and cerebral perfusion study (18.0%) in order. SPECT studies showed an increase from 47.2% to 63.5%. PET centers have also increased from 295 to 389, as compared to the last survey. The 112 PET centers have installed one or two in-house cyclotrons. PET studies showed 24.5% increase in 5 years, with oncology accounting for 88.9%. 18F-FDG accounted for 98.2% (630,570 examinations). PET examinations using 11C-methionine have decreased, with 2440 examinations in 2017. PET examinations using 13N-NH3 have been increasing, with 2363 examinations in 2017. The number of PET studies using 11C-PIB was 904. 131I-radioiodine targeted therapies showed an increase in 5 years (23.1%), including 4487 patients for thyroid cancer. Out-patient thyroid bed ablation therapy with 1,110 MBq of 131I accounted for 36.6% of cancer patients. The number of admission rooms increased from 135 to 157 in 5 years. The number of 223Ra targeted therapies for castration-resistant metastatic prostate cancer was 1194 patients. CONCLUSIONS: Single-photon examinations showed a continuous tendency toward a decline in the survey. In contrast, the number of hybrid SPECT/CT scanner examinations has increased. PET/CT study and radionuclide targeted therapy have steadily increased.
  • The Roles of Hypoxia Imaging Using 18F-Fluoromisonidazole Positron Emission Tomography in Glioma Treatment.
    Hirata K, Yamaguchi S, Shiga T, Kuge Y, Tamaki N
    Journal of clinical medicine, 8, 8, 2019年07月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Glioma is the most common malignant brain tumor. Hypoxia is closely related to the malignancy of gliomas, and positron emission tomography (PET) can noninvasively visualize the degree and the expansion of hypoxia. Currently, 18F-fluoromisonidazole (FMISO) is the most common radiotracer for hypoxia imaging. The clinical usefulness of FMISO PET has been established; it can distinguish glioblastomas from lower-grade gliomas and can predict the microenvironment of a tumor, including necrosis, vascularization, and permeability. FMISO PET provides prognostic information, including survival and treatment response information. Because hypoxia decreases a tumor's sensitivity to radiation therapy, dose escalation to an FMISO-positive volume is an attractive strategy. Although this idea is not new, an insufficient amount of evidence has been obtained regarding this concept. New tracers for hypoxia imaging such as 18F-DiFA are being tested. In the future, hypoxia imaging will play an important role in glioma management.
  • Biodistribution and radiation dosimetry of the novel hypoxia PET probe [18F]DiFA and comparison with [18F]FMISO.
    Watanabe S, Shiga T, Hirata K, Magota K, Okamoto S, Toyonaga T, Higashikawa K, Yasui H, Kobayashi J, Nishijima KI, Iseki K, Matsumoto H, Kuge Y, Tamaki N
    EJNMMI research, 9, 1, 60, 60, 2019年07月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: To facilitate hypoxia imaging in a clinical setting, we developed 1-(2,2-dihydroxymethyl-3-[18F]-fluoropropyl)-2-nitroimidazole ([18F]DiFA) as a new tracer that targets tumor hypoxia with its lower lipophilicity and efficient radiosynthesis. Here, we evaluated the radiation dosage, biodistribution, human safety, tolerability, and early elimination after the injection of [18F]DiFA in healthy subjects, and we performed a preliminary clinical study of patients with malignant tumors in a comparison with [18F]fluoromisonidazole ([18F]FMISO). RESULTS: The single administration of [18F]DiFA in 8 healthy male adults caused neither adverse events nor abnormal clinical findings. Dynamic and sequential whole-body scans showed that [18F]DiFA was rapidly cleared from all of the organs via the hepatobiliary and urinary systems. The whole-body mean effective dose of [18F]DiFA estimated by using the medical internal radiation dose (MIRD) schema with organ level internal dose assessment/exponential modeling (OLINDA/EXM) computer software 1.1 was 14.4 ± 0.7 μSv/MBq. Among the organs, the urinary bladder received the largest absorbed dose (94.7 ± 13.6 μSv/MBq). The mean absorbed doses of the other organs were equal to or less than those from other hypoxia tracers. The excretion of radioactivity via the urinary system was very rapid, reaching 86.4 ± 7.1% of the administered dose. For the preliminary clinical study, seven patients were subjected to [18F]FMISO and [18F]DiFA positron emission tomography (PET) at 48-h intervals to compare the two tracers' diagnostic ability for tumor hypoxia. The results of the tumor hypoxia evaluation by [18F]DiFA PET at 1 h and 2 h were not significantly different from those obtained with [18F]FMISO PET at 4 h ([18F]DiFA at 1 h, p = 0.32; [18F]DiFA at 2 h, p = 0.08). Moreover, [18F]DiFA PET at both 1 h (k = 0.68) and 2 h (k = 1.00) showed better inter-observer reproducibility than [18F]FMISO PET at 4 h (k = 0.59). CONCLUSION: [18F]DiFA is well tolerated, and its radiation dose is comparable to those of other hypoxia tracers. [18F]DiFA is very rapidly cleared via the urinary system. [18F]DiFA PET generated comparable images to [18F]FMISO PET in hypoxia imaging with shorter waiting time, demonstrating the promising potential of [18F]DiFA PET for hypoxia imaging and for a multicenter trial.
  • Volume-based glucose metabolic analysis of FDG PET/CT: The optimum threshold and conditions to suppress physiological myocardial uptake.
    Osamu Manabe, Markus Kroenke, Tadao Aikawa, Atsuto Murayama, Masanao Naya, Atsuro Masuda, Noriko Oyama-Manabe, Kenji Hirata, Shiro Watanabe, Tohru Shiga, Chietsugu Katoh, Nagara Tamaki
    Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology, 26, 3, 909, 918, 2019年06月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: FDG PET/CT plays a significant role in the diagnosis of inflammatory heart diseases and cardiac tumors. We attempted to determine the optimal FDG uptake threshold for volume-based analyses and to evaluate the relationship between the myocardial physiological uptake volume in FDG PET and several clinical factors. METHODS: A total of 190 patients were retrospectively analyzed. The cardiac metabolic volume (CMV) was defined as a volume within the boundary determined by a threshold (SUVmean of blood pool × 1.5). RESULTS: The SUVmean of the blood pool measured in the descending aorta (DA) (r = 0.86, intraclass correlation coefficient [ICC] = 0.93, P < 0.0001) and that in the left ventricle (LV) cavity (r = 0.87, ICC = 0.90, P < 0.0001) showed high inter-operator reproducibility. However, the SUVmean in the LV cavity showed a significant correlation with the CMV (P = 0.0002, r = 0.26). The CMV in the patients who fasted < 18 hours were significantly higher (49.7  ±  73.2 vs. 18.0  ±  53.8 mL, P = 0.0013) compared to the patients with > 18-hour fasting. The multivariate analysis demonstrated that only the fasting period > 18 hours was independently associated with CMV = 0. CONCLUSION: Our findings revealed that the DA is suitable to decide the threshold for the volume-based analysis. The fasting time was significantly associated with the cardiac FDG uptake.
  • Use of 18F-FDG PET/CT texture analysis to diagnose cardiac sarcoidosis.
    Osamu Manabe, Hiroshi Ohira, Kenji Hirata, Souichiro Hayashi, Masanao Naya, Ichizo Tsujino, Tadao Aikawa, Kazuhiro Koyanagawa, Noriko Oyama-Manabe, Yuuki Tomiyama, Keiichi Magota, Keiichiro Yoshinaga, Nagara Tamaki
    European journal of nuclear medicine and molecular imaging, 46, 6, 1240, 1247, 2019年06月, ［査読有り］, ［国際誌］
    英語, PURPOSE: 18F-fluorodeoxyglocose positron emission tomography (FDG PET) plays a significant role in the diagnosis of cardiac sarcoidosis (CS). Texture analysis is a group of computational methods for evaluating the inhomogeneity among adjacent pixels or voxels. We investigated whether texture analysis applied to myocardial FDG uptake has diagnostic value in patients with CS. METHODS: Thirty-seven CS patients (CS group), and 52 patients who underwent FDG PET/CT to detect malignant tumors with any FDG cardiac uptake (non-CS group) were studied. A total of 36 texture features from the histogram, gray-level co-occurrence matrix (GLCM), gray-level run length matrix (GLRLM), gray-level zone size matrix (GLZSM) and neighborhood gray-level difference matrix (NGLDM), were computed using polar map images. First, the inter-operator and inter-scan reproducibility of the texture features of the CS group were evaluated. Then, texture features of the patients with CS were compared to those without CS lesions. RESULTS: Twenty-eight of the 36 texture features showed high inter-operator reproducibility with intraclass correlation coefficients (ICCs) over 0.80. In addition, 17 of the 36 showed high inter-scan reproducibility with ICCs over 0.80. The SUVmax showed no difference between the CS and non-CS group [7.36 ± 2.77 vs. 8.78 ± 4.65, p = 0.45, area under the curve (AUC) = 0.60]. By contrast, 16 of the 36 texture features could distinguish CS from non-CS grsoup with AUC > 0.80. Multivariate logistic regression analysis after hierarchical clustering concluded that long-run emphasis (LRE; P = 0.0004) and short-run low gray-level emphasis (SRLGE; P = 0.016) were significant independent factors that could distinguish between the CS and non-CS groups. Specifically, LRE was significantly higher in CS than in non-CS (30.1 ± 25.4 vs. 11.4 ± 4.6, P < 0.0001), with high diagnostic ability (AUC = 0.91), and had high inter-operator reproducibility (ICC = 0.98). CONCLUSIONS: The texture analysis had high inter-operator and high inter-scan reproducibility. Some of texture features showed higher diagnostic value than SUVmax for CS diagnosis. Therefore, texture analysis may have a role in semi-automated systems for diagnosing CS.
  • A convolutional neural network-based system to prevent patient misidentification in FDG-PET examinations.
    Keisuke Kawauchi, Kenji Hirata, Chietsugu Katoh, Seiya Ichikawa, Osamu Manabe, Kentaro Kobayashi, Shiro Watanabe, Sho Furuya, Tohru Shiga
    Scientific reports, 9, 1, 7192, 7192, 2019年05月10日, ［査読有り］, ［国際誌］
    英語, Patient misidentification in imaging examinations has become a serious problem in clinical settings. Such misidentification could be prevented if patient characteristics such as sex, age, and body weight could be predicted based on an image of the patient, with an alert issued when a mismatch between the predicted and actual patient characteristic is detected. Here, we tested a simple convolutional neural network (CNN)-based system that predicts patient sex from FDG PET-CT images. This retrospective study included 6,462 consecutive patients who underwent whole-body FDG PET-CT at our institute. The CNN system was used for classifying these patients by sex. Seventy percent of the randomly selected images were used to train and validate the system; the remaining 30% were used for testing. The training process was repeated five times to calculate the system's accuracy. When images for the testing were given to the learned CNN model, the sex of 99% of the patients was correctly categorized. We then performed an image-masking simulation to investigate the body parts that are significant for patient classification. The image-masking simulation indicated the pelvic region as the most important feature for classification. Finally, we showed that the system was also able to predict age and body weight. Our findings demonstrate that a CNN-based system would be effective to predict the sex of patients, with or without age and body weight prediction, and thereby prevent patient misidentification in clinical settings.
  • Extraction of regions related to cardiac sarcoidosis in polar map images
    Ren Togo, Takahiro Ogawa, Osamu Manabe, Kenji Hirata, Tohru Shiga, Miki Haseyama
    2019 IEEE 1st Global Conference on Life Sciences and Technologies, LifeTech 2019, 237, 238, 2019年03月, ［査読有り］
    研究論文（国際会議プロシーディングス）
  • メルケル細胞癌におけるPET-CTのFDG集積に関する細胞学的検討　　　　　　　　　　　　　　　
    北村 真也, 柳 輝希, 高島 有香, 今福 恵輔, 秦 洋郎, 清水 宏, 平田 健司, 上原 治朗, 石田 雄大, 大塚 篤司
    日本皮膚科学会雑誌, 129, 3, 353, 353, (公社)日本皮膚科学会, 2019年03月
    日本語
  • Serum level of soluble interleukin-2 receptor is positively correlated with metabolic tumor volume on 18 F-FDG PET/CT in newly diagnosed patients with diffuse large B-cell lymphoma.
    Hajime Senjo, Minoru Kanaya, Koh Izumiyama, Koichiro Minauchi, Kenji Hirata, Akio Mori, Makoto Saito, Masanori Tanaka, Hiroaki Iijima, Eriko Tsukamoto, Kazuo Itoh, Shuichi Ota, Masanobu Morioka, Daigo Hashimoto, Takanori Teshima
    Cancer medicine, 8, 3, 953, 962, 2019年03月, ［国際誌］
    英語, 研究論文（学術雑誌）, Diffuse large B-cell lymphoma (DLBCL) is the most frequent subtype of non-Hodgkin lymphoma. High total metabolic tumor volume (TMTV) calculated using 18 F-FDG PET/CT images at diagnosis predicts poor prognosis of patients with DLBCL. However, high cost and poor access to the imaging facilities hamper wider use of 18 F-FDG PET/CT. In order to explore a surrogate marker for TMTV, we evaluated the correlation between the serum levels of soluble interleukin-2 receptor (sIL-2R) and TMTV in 64 patients with DLBCL, and the results were verified in an independent validation cohort of 86 patients. Serum levels of sIL-2R were significantly correlated with TMTV. ROC analysis revealed that the cutoff value of TMTV ≥150 cm3 or sIL-2R ≥ 1300 U/mL could predict failure to achieve EFS24 with areas under the curve (AUC) 0.706 and 0.758, respectively. Each of TMTV ≥150 cm3 and sIL-2R ≥1300 U/mL was significantly associated with worse 5-year overall survival and event-free survival. Importantly, each of sIL-2R <1300 U/mL or TMTV <150 cm3 identified patients with favorable prognosis among NCCN-IPI high-intermediate and high-risk group. Serum level of sIL-2R represents a convenient surrogate marker to estimate metabolic tumor burden measured by 18 F-FDG PET/CT that can predict treatment outcomes of patients with DLBCL.
  • A Nodular Lesion of the Foot Detected by 18F-FDG PET/CT in Mycosis Fungoides: A Plantar Wart.
    Yasuyuki Fujita, Ken Natsuga, Osamu Manabe, Kenji Hirata, Hiroshi Shimizu
    Clinical nuclear medicine, 44, 3, 244, 245, 2019年03月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, A 34-year-old Japanese woman presented with widespread scaly erythema that had enlarged over 2 years. A skin biopsy revealed the diagnosis of mycosis fungoides (patch stage, T1b N0 M0 B0), a most frequent cutaneous T-cell lymphoma. F-FDG PET/CT scan unexpectedly showed intense uptake on the left sole, which suggested a tumorous mycosis fungoides lesion (SUVmax = 6.2). Careful examination revealed the mass to be a typical plantar wart of 2 cm in diameter that the patient had not recognized. With repeated cryotherapy, the wart disappeared in 6 months, and follow-up F-FDG PET/CT showed no abnormal uptake on the left sole.
  • Voxel based comparison and texture analysis of 18F-FDG and 18F-FMISO PET of patients with head-and-neck cancer.
    Kroenke M, Hirata K, Gafita A, Watanabe S, Okamoto S, Magota K, Shiga T, Kuge Y, Tamaki N
    PloS one, 14, 2, e0213111, 2019年, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Hypoxia can induce radiation resistance and is an independent prognostic marker for outcome in head and neck cancer. As 18F-FMISO (FMISO), a hypoxia tracer for PET, is far less common than 18F-FDG (FDG) and two separate PET scans result in doubled cost and radiation exposure to the patient, we aimed to predict hypoxia from FDG PET with new techniques of voxel based analysis and texture analysis. METHODS: Thirty-eight patients with head-and-neck cancer underwent consecutive FDG and FMISO PET scans before any treatment. ROIs enclosing the primary cancer were compared in a voxel-by-voxel manner between FDG and FMISO PET. Tumour hypoxia was defined as the volume with a tumour-to-muscle ratio (TMR) > 1.25 in the FMISO PET and hypermetabolic volume was defined as >50% SUVmax in the FDG PET. The concordance rate was defined as percentage of voxels within the tumour which were both hypermetabolic and hypoxic. 38 different texture analysis (TA) parameters were computed based on the ROIs and correlated with presence of hypoxia. RESULTS: Within the hypoxic tumour regions, the FDG uptake was twice as high as in the non-hypoxic tumour regions (SUVmean 10.9 vs. 5.4; p<0.001). A moderate correlation between FDG and FMISO uptake was found by a voxel-by-voxel comparison (r = 0.664 p<0.001). The average concordance rate was 25% (± 22%). Entropy was the TA parameter showing the highest correlation with hypoxia (r = 0.524 p<0.001). CONCLUSION: FDG uptake was higher in hypoxic tumour regions than in non-hypoxic regions as expected by tumour biology. A moderate correlation between FDG and FMISO PET was found by voxel-based analysis. TA yielded similar results in FDG and FMISO PET. However, it may not be possible to predict tumour hypoxia even with the help of texture analysis.
  • Cardiac sarcoidosis classification with deep convolutional neural network-based features using polar maps.
    Ren Togo, Kenji Hirata, Osamu Manabe, Hiroshi Ohira, Ichizo Tsujino, Keiichi Magota, Takahiro Ogawa, Miki Haseyama, Tohru Shiga
    Computers in biology and medicine, 104, 81, 86, 2019年01月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, AIMS: The aim of this study was to determine whether deep convolutional neural network (DCNN)-based features can represent the difference between cardiac sarcoidosis (CS) and non-CS using polar maps. METHODS: A total of 85 patients (33 CS patients and 52 non-CS patients) were analyzed as our study subjects. One radiologist reviewed PET/CT images and defined the left ventricle region for the construction of polar maps. We extracted high-level features from the polar maps through the Inception-v3 network and evaluated their effectiveness by applying them to a CS classification task. Then we introduced the ReliefF algorithm in our method. The standardized uptake value (SUV)-based classification method and the coefficient of variance (CoV)-based classification method were used as comparative methods. RESULTS: Sensitivity, specificity and the harmonic mean of sensitivity and specificity of our method with the ReliefF algorithm were 0.839, 0.870 and 0.854, respectively. Those of the SUVmax-based classification method were 0.468, 0.710 and 0.564, respectively, and those of the CoV-based classification method were 0.655, 0.750 and 0.699, respectively. CONCLUSION: The DCNN-based high-level features may be more effective than low-level features used in conventional quantitative analysis methods for CS classification.
  • Integrating quantitative morphological and intratumoural textural characteristics in FDG-PET for the prediction of prognosis in pharynx squamous cell carcinoma patients.
    N Fujima, K Hirata, T Shiga, R Li, K Yasuda, R Onimaru, K Tsuchiya, S Kano, T Mizumachi, A Homma, K Kudo, H Shirato
    Clinical radiology, 73, 12, 1059.e1-1059.e8, 2018年12月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, AIM: To assess potential prognostic factors in pharynx squamous cell carcinoma (SCC) patients by quantitative morphological and intratumoural characteristics obtained by 2-[18F]-fluoro-2-deoxy-d-glucose positron-emission tomography/computed tomography (FDG-PET/CT). MATERIALS AND METHODS: The cases of 54 patients with pharynx SCC who underwent chemoradiation therapy were analysed retrospectively. Using their FDG-PET data, the quantitative morphological and intratumoural characteristics of 14 parameters were calculated. The progression-free survival (PFS) and overall survival (OS) information was obtained from patient medical records. Univariate and multivariate analyses were performed to assess the 14 quantitative parameters as well as the T-stage, N-stage, and tumour location data for their relation to PFS and OS. When an independent predictor was suggested in the multivariate analysis, the parameter was further assessed using the Kaplan-Meier method. RESULTS: In the assessment of PFS, the univariate and multivariate analyses indicated the following as independent predictors: the texture parameter of homogeneity and the morphological parameter of sphericity. In the Kaplan-Meier analysis, the PFS rate was significantly improved in the patients who had both a higher value of homogeneity (p=0.01) and a higher value of sphericity (p=0.002). With the combined use of homogeneity and sphericity, the patients with different PFS rates could be divided more clearly. CONCLUSION: The quantitative parameters of homogeneity and sphericity obtained by FDG-PET can be useful for the prediction of the PFS of pharynx SCC patients, especially when used in combination.
  • 15O-水心筋血流PETにおけるMonte Carlo scaling複合型SSS散乱補正の検討　　　　　　　　　　　　　　　
    孫田 惠一, 志賀 哲, 真鍋 治, 納谷 昌直, 相川 忠夫, 新山 大樹, 平田 健司, 加藤 千恵次, 藤田 勝久, 玉木 長良
    核医学, 55, Suppl., S212, S212, (一社)日本核医学会, 2018年11月, ［査読有り］
    日本語
  • Which is the proper reference tissue for measuring the change in FDG PET metabolic volume of cardiac sarcoidosis before and after steroid therapy?
    Sho Furuya, Osamu Manabe, Hiroshi Ohira, Kenji Hirata, Tadao Aikawa, Masanao Naya, Ichizo Tsujino, Kazuhiro Koyanagawa, Toshihisa Anzai, Noriko Oyama-Manabe, Tohru Shiga
    EJNMMI research, 8, 1, 94, 94, 2018年10月05日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Cardiac sarcoidosis (CS) is a rare but potentially life-threatening disease that causes conduction disturbance, systolic dysfunction, and, most notably, sudden cardiac death. 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) plays important roles not only in diagnosing CS but also in evaluating the effects of anti-inflammatory therapy. A volume-based analysis of parameters measured by FDG PET, so-called cardiac metabolic volume (CMV), has emerged as a new assessment tool. CMV is measured as the volume within the boundary determined by a reference tissue such as the liver and the blood pool uptake. However, there is a possibility that oral steroid therapy could lead to variations of the liver and the blood pool uptake. Here, we attempted to evaluate the steroid effects on the liver and the blood pool uptake. A total of 38 CS patients who underwent FDG PET/CT before and during steroid therapy were retrospectively enrolled. Volumes of interest (VOIs) were placed in the right lobe of the liver and descending aorta (DA). The maximum standardized uptake value (SUVmax), SUVmean, and SUVpeak of the liver and DA were compared between time points before and during steroid therapy. RESULTS: The SUVmax, SUVmean, and SUVpeak of the liver during steroid therapy significantly increased from the time point before the therapy (SUVmax 3.5 ± 0.4 vs. 3.8 ± 0.6, p = 0.014; SUVmean 2.7 ± 0.3 vs. 3.0 ± 0.5, p = 0.0065; SUVpeak 3.0 ± 0.4 vs. 3.4 ± 0.6, p = 0.006). However, the SUVmax, SUVmean, and SUVpeak in the DA did not significantly change (SUVmax 2.2 ± 0.3 vs. 2.2 ± 0.4, p = 0.46; SUVmean 1.9 ± 0.3 vs. 2.0 ± 0.4, p = 0.56; SUVpeak 2.0 ± 0.3 vs. 2.0 ± 0.3, p = 0.70). CONCLUSIONS: We measured FDG uptake in the liver and blood pool before and during steroid therapy. Steroid therapy increased the liver uptake but not the blood pool uptake. Our findings suggested that the DA uptake is a more suitable threshold than liver uptake to evaluate therapeutic effects using volume-based analysis of cardiac FDG PET.
  • Volume-based parameters on FDG PET may predict the proliferative potential of soft-tissue sarcomas.
    Kitao T, Shiga T, Hirata K, Sekizawa M, Takei T, Yamashiro K, Tamaki N
    Annals of nuclear medicine, 33, 1, 22, 31, 2018年09月, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, INTRODUCTION: Soft-tissue sarcomas (STS) are rare types of tumors that have variable levels of tumor differentiation. F-18 fluorodeoxyglucose positron emission tomography (FDG PET) has been established as an useful tool for STS patients, and the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are reported to be useful in various cancers. We compared the diagnostic value of four PET parameters (maximum standardized uptake value [SUVmax], SUVmean, MTV, and TLG) from two acquisition timings for predicting the expression of the pathological marker of cell proliferation Ki-67, based on pathological investigation. MATERIALS AND METHODS: In this retrospective study, we investigated 20 patients (59 ± 19 years old, 18-87 years old) with pathologically confirmed STS who underwent FDG PET before surgical intervention. The patients fasted ≥ 6 h before the intravenous injection of FDG. The whole body was scanned twice; at an early phase (61.5 ± 2.6 min) and at a delayed phase (118.0 ± 2.1 min) post-injection. The SUVmax, SUVmean, MTV, and TLG of the primary lesion were measured with a tumor boundary determined by SUV ≥ 2.0. Ki-67 was measured using MIB-1 immunohistochemistry. We used Pearson's correlation coefficient to analyze the relationships between the PET parameters and Ki-67 expressions. The Kaplan-Meier analysis with the log-rank test was performed to compare overall survival between high-group and low-group at each of the four PET parameters and Ki-67 expression. RESULTS: All four PET parameters at each phase showed significant correlations with Ki-67. Among them, the Pearson's correlation coefficient (r) was largest for TLG (r = 0.76 and 0.77 at the early and delayed phases, respectively), followed by MTV (0.70 and 0.72), SUVmax (r = 0.65 and 0.66), and SUVmean (r = 0.62 and r = 0.64). From early to delayed phases, the SUVmax and SUVmean both increased in all 20 patients, whereas the MTV and TLG increased in 13/20 (65%) and 16/20 (80%) patients, respectively. None of the %increases of the PET parameters were significantly correlated with Ki-67. The overall survival was shorter for high-SUVmax, high-SUVmean, high-TLG, and high-Ki-67 groups than the other groups, although the difference did not reach statistical significance. CONCLUSION: The SUVmax, SUVmean, MTV, and TLG acquired at both 1 and 2 h after injection showed significant correlations with Ki-67. Among them, correlation coefficient with Ki-67 expression was highest for TLG, although the best parameter should be determined in a larger population. The delayed-phase FDG PET was equally useful as that of early-phase to predict tumor aggressiveness in STS.
  • Semi-quantitative analysis of pre-treatment morphological and intratumoral characteristics using 18F-fluorodeoxyglucose positron-emission tomography as predictors of treatment outcome in nasal and paranasal squamous cell carcinoma.
    Noriyuki Fujima, Kenji Hirata, Tohru Shiga, Koichi Yasuda, Rikiya Onimaru, Kazuhiko Tsuchiya, Satoshi Kano, Takatsugu Mizumachi, Akihiro Homma, Kohsuke Kudo, Hiroki Shirato
    Quantitative imaging in medicine and surgery, 8, 8, 788, 795, 2018年09月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Background: To investigate the utility of quantitative morphological and intratumoral characteristics obtained by 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) for the prediction of treatment outcome in patients with nasal or paranasal cavity squamous cell carcinoma (SCC). Methods: Twenty-four patients with nasal or paranasal cavity SCC who received curative non-surgical therapy (a combination of super-selective arterial cisplatin infusion and radiotherapy) were retrospectively analyzed. From pre-treatment FDG-PET data, a total of 13 parameters of quantitative morphological characteristics (tumor volume, surface area and sphericity), intratumoral characteristics (the maximum and mean standard uptake value, three intratumoral histogram and four textural parameters) and total lesion glycolysis (TLG) were respectively calculated. Information regarding the treatment outcome was determined from the histological diagnosis or clinical follow-up. Each of the 13 quantitative parameters as well as T- and N-stage was assessed for its relation to treatment outcome of local control or failure. Results: In univariate analysis, significant differences in surface area and sphericity between the local control and failure groups were observed. The receiver operating characteristic (ROC) curve analysis showed that sphericity had the highest accuracy of 0.88. In the multivariate analysis, sphericity was revealed as an independent predictor of the local control or failure. Conclusions: The quantitative parameters of sphericity are useful to predict the treatment outcome in patients with nasal or paranasal SCC.
  • Early prediction of lenvatinib treatment efficacy by using 18F-FDG PET/CT in patients with unresectable or advanced thyroid carcinoma that is refractory to radioiodine treatment: a protocol for a non-randomized single-arm multicenter observatio
    Takeuchi S, Shiga T, Hirata K, Taguchi J, Magota K, Ariga S, Gouda T, Ohhara Y, Homma R, Shimizu Y, Kinoshita I, Tsuji Y, Homma A, Iijima H, Tamaki N, Dosaka-Akita H
    BMJ open, 8, 8, e021001, 2018年08月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, INTRODUCTION: Lenvatinib, an oral molecular targeted drug, is used to treat patients with unresectable or advanced thyroid carcinoma that is refractory to radioiodine treatment. Effective methods for evaluating molecular targeted drugs are a critical unmet need owing to their expensive costs and unique adverse events. The aim of this study is to determine whether 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT at 1 week after commencing lenvatinib can predict treatment outcomes. DESIGN AND METHODS: This study is planned as a non-randomised single-arm multicentre study; patients with pathologically confirmed differentiated thyroid carcinoma (DTC) with lesions that are refractory to radioiodine treatment are eligible. The main exclusion criteria are medullary or anaplastic carcinoma, prior treatment with chemotherapy, poor general condition and thromboembolism-requiring treatment. Patients to be included in the study will be treated with lenvatinib and undergo FDG-PET/CT examination twice: before and 1 week after the initiation of treatment. Contrast-enhanced CT, the gold standard for evaluation, will be performed at least 4 weeks after the initiation of treatment. The primary objective is to evaluate the ability of the lesion maximum standard uptake value for FDG PET/CT performed 1 week after the initiation of treatment to predict outcomes compared with the response evaluation obtained via contrast-enhanced CT performed at least 4 weeks after the initiation of treatment. ETHICS AND DISSEMINATION: This study is conducted in accordance with the Declaration of Helsinki and has received ethical approval from the institutional review board of the Hokkaido University Hospital (approval number: 015-402). The results of this study will be disseminated through a presentation at a conference and the publication of the data in a peer-reviewed journal. The study will be implemented and reported in line with the SPIRIT statement. TRIAL REGISTRATION NUMBER: UMIN000022592.
  • The prognostic improvement of add-on bevacizumab for progressive disease during concomitant temozolomide and radiation therapy in the patients with glioblastoma and anaplastic astrocytoma.
    Shigeru Yamaguchi, Yukitomo Ishi, Hiroaki Motegi, Michinari Okamoto, Hiroyuki Kobayashi, Kenji Hirata, Yoshitaka Oda, Shinya Tanaka, Shunsuke Terasaka, Kiyohiro Houkin
    Journal of neurosurgical sciences, 64, 6, 502, 508, 2018年07月09日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Although newly diagnosed high-grade glioma patients in Japan can receive bevacizumab (BEV) as first-line chemotherapy, randomized clinical trials have not shown a survival benefit for BEV for these patients. In this study, we investigated whether selective add-on BEV for patients with newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA) improves prognosis, in cases where tumors were continuously growing during radiotherapy concomitant with temozolomide (TMZ). METHODS: We conducted a retrospective survey of the overall survival (OS) of patients with GBM/AAs who were treated in our institution between 2006 and 2016. Patients whose tumors were continuously growing regardless of radiotherapy were categorized as the "progressive" group; remaining patients were categorized as the "non-progressive" group. Since 2013, patients in the "progressive" group received add-on BEV therapy with the Stupp regimen during or just after radiotherapy. RESULTS: Of 151 GBM/AA patients, 34 (22.5%) were categorized in the "progressive" group. Median OSs of the "progressive" and "non-progressive" groups were 13.2 months and 25.3 months, respectively (P < 0.001). Twelve patients in the "progressive" group received add-on BEV therapy, and their median OS was 20.2 months; whereas for the remaining 22 patients in the "progressive" group who were treated before the BEV era, their median OS was 10.5 months. In the "progressive" group, add-on BEV significantly extended OS (P = 0.018) and was the lone clinical factor of better prognosis. CONCLUSIONS: We found that, for patients with GBM/AAs whose tumors were continuously growing during radiotherapy, add-on BEV treatment resulted in survival benefits.
  • 第8回全国核医学診療実態調査報告書
    絹谷 清剛, 西山 佳宏, 加藤 隆司, 萱野 大樹, 佐藤 修平, 田代 学, 巽 光朗, 橋本 禎介, 馬場 眞吾, 平田 健司, 吉村 真奈, 米山 寛人, (公社)日本アイソトープ協会医学・薬学部会全国核医学診療実態調査専門委員会
    Radioisotopes, 67, 7, 339, 387, (公社)日本アイソトープ協会, 2018年07月
    日本語
  • Use of deep convolutional neural network-based features for detection of cardiac sarcoidosis from polar map　　　　　　　　　　　　　　　
    Ren Togo, Kenji Hirata, Osamu Manabe, Hiroshi Ohira, Ichizo Tsujino, Takahiro Ogawa, Miki Haseyama, Tohru Shiga
    Society of Nuclear Medicine and Molecular Imaging Annual Meeting (SNMMI), 2018年06月, ［査読有り］
    英語, 研究論文（国際会議プロシーディングス）
  • Strategy to develop convolutional neural network-based classifier for diagnosis of whole-body FDG PET images
    Keisuke Kawauchi, Kenji Hirata, Seiya Ichikawa, Osamu Manabe, Kentaro Kobayashi, Shiro Watanabe, Miki Haseyama, Takahiro Ogawa, Ren Togo, Tohru Shiga, Chietsugu Katoh
    JOURNAL OF NUCLEAR MEDICINE, 59, 2018年05月, ［査読有り］
    英語, 研究論文（国際会議プロシーディングス）
  • Hypoxic volume evaluated by 18 F-fluoromisonidazole positron emission tomography (FMISO-PET) may be a prognostic factor in patients with oral squamous cell carcinoma: preliminary analyses
    J. Sato, Y. Kitagawa, S. Watanabe, T. Asaka, N. Ohga, K. Hirata, T. Shiga, A. Satoh, N. Tamaki
    International Journal of Oral and Maxillofacial Surgery, 47, 5, 553, 560, 2018年05月01日
    研究論文（学術雑誌）
  • Relationship between intelligence quotient (IQ) and cerebral metabolic rate of oxygen in patients with neurobehavioural disability after traumatic brain injury.
    Abiko K, Shiga T, Katoh C, Hirata K, Kuge Y, Kobayashi K, Ikeda S, Ikoma K
    Brain injury, 32, 11, 1367, 1372, 2018年, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: Cerebral metabolism may play a significant role in neurobehavioural disability following traumatic brain injury (TBI). In this study, we examined the relationship between intelligence quotient (IQ) and the cerebral metabolic rate of oxygen (CMRO2) in the lateral prefrontal cortex, which was measured by 15O-labelled gas positron emission tomography (PET), in patients with TBI. MATERIALS AND METHODS: The subjects were 12 patients (eight males and four females) who suffered from neurobehavioural disability following TBI. Their mean age was 33.3 years. The cause of injury was traffic accidents in all patients and the mean period after injury was 44.8 months. These patients underwent 15O-labelled gas PET and tests using either the Wechsler Adult Intelligence Scale-Revised (WAIS-R) or the Wechsler Intelligence Scale for Children-Revised (WISC-R). Pearson's correlation between CMRO2 and total IQ (TIQ) was calculated. RESULTS: A statistically significant correlation was observed between TIQ and CMRO2 in the right Brodmann areas (BAs) 44 and 45. The lower the WAIS score, the higher the CMRO2 in both areas. CONCLUSION: Neurological function negatively correlated with the metabolism of oxygen. It was possible that changes in brain networks increased the neuronal activity in the undamaged areas and that the increased activity compensated for the function decline.
  • Quantification of myocardial blood flow with 11C-hydroxyephedrine dynamic PET: comparison with 15O-H2O PET.
    Yuji Hiroshima, Osamu Manabe, Masanao Naya, Yuuki Tomiyama, Keiichi Magota, Masahiko Obara, Tadao Aikawa, Noriko Oyama-Manabe, Keiichiro Yoshinaga, Kenji Hirata, Markus Kroenke, Nagara Tamaki, Chietsugu Katoh
    Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology, 27, 4, 1118, 1125, 2017年12月21日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: 11C-hydroxyephedrine (HED) PET has been used to evaluate the myocardial sympathetic nervous system (SNS). Here we sought to establish a simultaneous approach for quantifying both myocardial blood flow (MBF) and the SNS from a single HED PET scan. METHODS: Ten controls and 13 patients with suspected cardiac disease were enrolled. The inflow rate of 11C-HED (K1) was obtained using a one-tissue-compartment model. We compared this rate with the MBF derived from 15O-H2O PET. In the controls, the relationship between K 1 from 11C-HED PET and the MBF from 15O-H2O PET was linked by the Renkin-Crone model. RESULTS: The relationship between K 1 from 11C-HED PET and the MBF from 15O-H2O PET from the controls' data was approximated as follows: K 1  =  (1 - 0.891 * exp(- 0.146/MBF)) * MBF. In the validation set, the correlation coefficient demonstrated a significantly high relationship for both the whole left ventricle (r = 0.95, P < 0.001) and three coronary territories (left anterior descending artery: r = 0.96, left circumflex artery: r = 0.81, right coronary artery: r =  0.86; P < 0.001, respectively). CONCLUSION: 11C-HED can simultaneously estimate MBF and sympathetic nervous function without requiring an additional MBF scan for assessing mismatch areas between MBF and SNS.
  • Characteristics of immunoglobulin G4-related aortitis/periaortitis and periarteritis on fluorodeoxyglucose positron emission tomography/computed tomography co-registered with contrast-enhanced computed tomography.
    Satoshi Yabusaki, Noriko Oyama-Manabe, Osamu Manabe, Kenji Hirata, Fumi Kato, Noriyuki Miyamoto, Yoshihiro Matsuno, Kohsuke Kudo, Nagara Tamaki, Hiroki Shirato
    EJNMMI research, 7, 1, 20, 20, 2017年12月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: We aimed to assess the positivity, distribution, quantitative degree of vessel inflammation, and clinical characteristics of IgG4-related aortitis/periarteritis and periarteritis (IgG4-aortitis), and to examine the difference in these characteristics between cases with and without IgG4-aortitis, using fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) co-registered with contrast-enhanced CT (CECT). We retrospectively evaluated 37 patients with IgG4-related disease (IgG4-RD) who underwent both FDG-PET/CT and CECT. The arterial SUVmax and its value normalized to the background venous blood pool (BP)-the target-to-background ratio (TBR) in the entire aorta and the major first branches-were measured. Active vascular inflammation was considered in cases with a higher FDG uptake than BP and a thickened arterial wall (>2 mm). RESULTS: Fifteen (41%) patients exhibited IgG4-aortitis. Most patients (80%) showed multiple region involvement. The entire aorta, including the major first branches, were involved, typically showing a thickened wall and high FDG uptakes. The most common site was the iliac arteries (35%), followed by the infrarenal abdominal aorta (33%), thoracic aorta (8%), first branches of the thoracic aorta (8%), suprarenal abdominal aorta (6%), and the first branches of the abdominal aorta (5%). The IgG4-aortitis-positive vessel regions were thickened, with an average maximal wall thickness of 6.3 ± 2.9 mm. The SUVmax and TBR values were significantly higher in the IgG4-aortitis-positive regions (median 3.7 [1.6-5.5] and 2.1 [1.4-3.7], respectively) than in the IgG4-aortitis-negative regions (median 2.1 [1.2-3.7] and 1.3 [0.9-2.3], respectively; p < 0.0001). The IgG4-aortitis-positive group patients were older (69.5 ± 6.0 vs. 63.3 ± 12.6 years, respectively) and had a higher male predominance (80 vs. 55%, respectively) than the negative group, although the differences were not significant (p = 0.17 and p = 0.06, respectively). CONCLUSIONS: We investigated the image characteristics of IgG4-aortitis. The entire aorta and major branches can be involved with more than 2-fold higher FDG uptake than the venous background pool, and with wall thickening. The most common involved site is the iliac arteries, followed by the infrarenal abdominal aorta.
  • PET/CT scanning with 3D acquisition is feasible for quantifying myocardial blood flow when diagnosing coronary artery disease.
    Osamu Manabe, Masanao Naya, Tadao Aikawa, Masahiko Obara, Keiichi Magota, Markus Kroenke, Noriko Oyama-Manabe, Kenji Hirata, Daiki Shinyama, Chietsugu Katoh, Nagara Tamaki
    EJNMMI research, 7, 1, 52, 52, 2017年12月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: The quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR) are useful approaches for evaluating the functional severity of coronary artery disease (CAD). 15O-water positron emission tomography (PET) is considered the gold standard method for MBF quantification. However, MBF measurements in 15O-water PET with three-dimensional (3D) data acquisition, attenuation correction using computed tomography (CT), and time of flight have not been investigated in detail or validated. We conducted this study to evaluate the diagnostic potential of MBF measurements using PET/CT for a comparison of a control group and patients suspected of having CAD. RESULTS: Twenty-four patients with known or suspected CAD and eight age-matched healthy volunteers underwent rest and pharmacological stress perfusion studies with 15O-water PET/CT. The whole and three regional (left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) territory) MBF values were estimated. The CFR was computed as the ratio of the MBF during adenosine triphosphate-induced stress to the MBF at rest. The inter-observer variability was assessed by two independent observers. PET/CT using a 15O-water dose of 500 MBq and 3D data acquisition showed good image quality. A strong inter-observer correlation was detected in both the whole MBF analysis and the regional analysis with high intra-class correlation coefficients (r > 0.90, p < 0.001). Regional MBF at rest (LAD, 0.82 ± 0.15 ml/min/g; LCX, 0.83 ± 0.17 ml/min/g; RCA, 0.71 ± 0.20 ml/min/g; p = 0.74), MBF at stress (LAD, 3.77 ± 1.00 ml/min/g; LCX, 3.56 ± 1.01 ml/min/g; RCA, 3.27 ± 1.04 ml/min/g; p = 0.62), and CFR (LAD, 4.64 ± 0.90; LCX, 4.30 ± 0.64; RCA, 4.64 ± 0.96; p = 0.66) of the healthy volunteers showed no significant difference among the three regions. The global CFR of the patients was significantly lower than that of the volunteers (2.75 ± 0.81 vs. 4.54 ± 0.66, p = 0.0002). The regional analysis of the patients demonstrated that the CFR tended to be lower in the stenotic region compared to the non-stenotic region (2.43 ± 0.81 vs. 2.95 ± 0.92, p = 0.052). CONCLUSIONS: 15O-water PET/CT with 3D data acquisition can be reliably used for the quantification of functional MBF and CFR in CAD patients.
  • Scatter Correction with Combined Single-Scatter Simulation and Monte Carlo Simulation Scaling Improved the Visual Artifacts and Quantification in 3-Dimensional Brain PET/CT Imaging with O-15-Gas Inhalation
    Keiichi Magota, Tohru Shiga, Yukari Asano, Daiki Shinyama, Jinghan Ye, Amy E. Perkins, Piotr J. Maniawski, Takuya Toyonaga, Kentaro Kobayashi, Kenji Hirata, Chietsugu Katoh, Naoya Hattori, Nagara Tamaki
    JOURNAL OF NUCLEAR MEDICINE, 58, 12, 2020, 2025, 2017年12月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Present and future roles of FDG-PET/CT imaging in the management of gastrointestinal cancer: an update.
    Kazuhiro Kitajima, Masatoyo Nakajo, Hayato Kaida, Ryogo Minamimoto, Kenji Hirata, Masakatsu Tsurusaki, Hiroshi Doi, Yoshiko Ueno, Keitaro Sofue, Yukihisa Tamaki, Koichiro Yamakado
    Nagoya journal of medical science, 79, 4, 527, 543, 2017年11月, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, Positron emission tomography/computed tomography (PET/CT) integrated with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) is a useful tool for acquisition of both glucose metabolism and anatomic imaging data, as only a single device and one diagnostic session is required, thus opening a new field in clinical oncologic imaging. FDG-PET/CT has been successfully used for initial staging, restaging, assessment of early treatment response, evaluation of metastatic disease response, and prognostication of intestinal cancer as well as various malignant tumors. We reviewed the current status and role of FDG-PET/CT for management of patients with esophageal cancer, gastric cancer, and colorectal cancer, with focus on both its usefulness and limitations.
  • Players of 'hypoxia orchestra' - what is the role of FMISO?
    Takuya Toyonaga, Kenji Hirata, Tohru Shiga, Tamaki Nagara
    EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, 44, 10, 1679, 1681, 2017年09月, ［査読有り］
    英語
  • Dual Isotope SPECT Study With Epilepsy Patients Using Semiconductor SPECT System
    Tohru Shiga, Atsuro Suzuki, Kotarou Sakurai, Tsugiko Kurita, Wataru Takeuchi, Takuya Toyonaga, Kenji Hirata, Keiji Kobashi, Chietsugu Katoh, Naoki Kubo, Nagara Tamaki
    CLINICAL NUCLEAR MEDICINE, 42, 9, 663, 668, 2017年09月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • F-18-Fluoromisonidazole positron emission tomography (FMISO-PET) may reflect hypoxia and cell proliferation activity in oral squamous cell carcinoma
    Jun Sato, Yoshimasa Kitagawa, Shiro Watanabe, Takuya Asaka, Noritaka Ohga, Kenji Hirata, Shozo Okamoto, Tohru Shiga, Masanobu Shindoh, Yuji Kuge, Nagara Tamaki
    ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY ORAL RADIOLOGY, 124, 3, 261, 270, 2017年09月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • 心サルコイドーシスにおけるFDG集積定量評価の再現性　　　　　　　　　　　　　　　
    真鍋 治, 平田 健司, 大平 洋, 納谷 昌直, 相川 忠夫, 真鍋 徳子, 志賀 哲
    核医学, 54, Suppl., S174, S174, (一社)日本核医学会, 2017年09月, ［査読有り］
    日本語
  • Breast cancer detected as an incidental finding on 99mTc-MIBI scintigraphy.
    Toshihiro Homma, Osamu Manabe, Kazuomi Ichinokawa, Hiroko Yamashita, Noriko Oyama-Manabe, Fumi Kato, Kenji Hirata, Markus Kroenke, Nagara Tamaki
    Acta radiologica open, 6, 7, 2058460117715665, 2058460117715665, 2017年07月, ［査読有り］, ［国際誌］
    英語, We report a case of breast cancer detected as an incidental finding on 99mTc-MIBI scintigraphy. 99mTc-MIBI scintigraphy is usually used to evaluate cardiac perfusion or to detect ectopic parathyroid adenomas; however, it is also known to sensitively detect breast cancer. Accordingly, a few reports have described the incidental detection of breast cancer by 99mTc-MIBI scintigraphy performed to detect parathyroid adenoma. Our present case underscores the importance of attending to any incidental findings when searching for parathyroid adenomas using 99mTc-MIBI scintigraphy.
  • F-18-FDG PET findings of pericardial lymphangiohemangioma
    Tadao Aikawa, Masanao Naya, Noriko Oyama-Manabe, Satoshi Maekawa, Hideo Nambu, Hirofumi Mitsuyama, Kenji Hirata, Hiromi Kanno-Okada, Hiroyuki Tsutsui
    JOURNAL OF NUCLEAR CARDIOLOGY, 24, 3, 1107, 1109, 2017年06月, ［査読有り］
    英語
  • Predicting hypoxia using texture parameters on CT in patients with non-small cell lung cancer
    Shiro Watanabe, Tohru Shiga, Kenji Hirata, Tetsuya Inoue, Shozo Okamoto, Takuya Toyonaga, Keiichi Magota, Ken-ichi Nishijima, Yuji Kuge, Nagara Tamaki
    JOURNAL OF NUCLEAR MEDICINE, 58, 2017年05月, ［査読有り］
    英語
  • Convolutional neural network (CNN) of MRI and FDG-PET images may predict hypoxia in glioblastoma.
    Takuya Toyonaga, Tohru Shiga, Kenji Hirata, Shigeru Yamaguchi, Wataru Takeuchi, Kohsuke Kudo, Keiichi Magota, Osamu Manabe, Kentaro Kobayashi, Shiro Watanabe, Yuji Kuge, Nagara Tamaki
    JOURNAL OF NUCLEAR MEDICINE, 58, 2017年05月, ［査読有り］
    英語
  • Hypoxic glucose metabolism in glioblastoma as a potential prognostic factor.
    Takuya Toyonaga, Shigeru Yamaguchi, Kenji Hirata, Kentaro Kobayashi, Osamu Manabe, Shiro Watanabe, Shunsuke Terasaka, Hiroyuki Kobayashi, Naoya Hattori, Tohru Shiga, Yuji Kuge, Shinya Tanaka, Yoichi M Ito, Nagara Tamaki
    European journal of nuclear medicine and molecular imaging, 44, 4, 611, 619, 2017年04月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: Metabolic activity and hypoxia are both important factors characterizing tumor aggressiveness. Here, we used F-18 fluoromisonidazole (FMISO) and F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) to define metabolically active hypoxic volume, and investigate its clinical significance in relation to progression free survival (PFS) and overall survival (OS) in glioblastoma patients. EXPERIMENTAL DESIGN: Glioblastoma patients (n = 32) underwent FMISO PET, FDG PET, and magnetic resonance imaging (MRI) before surgical intervention. FDG and FMISO PET images were coregistered with gadolinium-enhanced T1-weighted MR images. Volume of interest (VOI) of gross tumor volume (GTV) was manually created to enclose the entire gadolinium-positive areas. The FMISO tumor-to-normal region ratio (TNR) and FDG TNR were calculated in a voxel-by-voxel manner. For calculating TNR, standardized uptake value (SUV) was divided by averaged SUV of normal references. Contralateral frontal and parietal cortices were used as the reference region for FDG, whereas the cerebellar cortex was used as the reference region for FMISO. FDG-positive was defined as the FDG TNR ≥1.0, and FMISO-positive was defined as FMISO TNR ≥1.3. Hypoxia volume (HV) was defined as the volume of FMISO-positive and metabolic tumor volume in hypoxia (hMTV) was the volume of FMISO/FDG double-positive. The total lesion glycolysis in hypoxia (hTLG) was hMTV × FDG SUVmean. The extent of resection (EOR) involving cytoreduction surgery was volumetric change based on planimetry methods using MRI. These factors were tested for correlation with patient prognosis. RESULTS: All tumor lesions were FMISO-positive and FDG-positive. Univariate analysis indicated that hMTV, hTLG, and EOR were significantly correlated with PFS (p = 0.007, p = 0.04, and p = 0.01, respectively) and that hMTV, hTLG, and EOR were also significantly correlated with OS (p = 0.0028, p = 0.037, and p = 0.014, respectively). In contrast, none of FDG TNR, FMISO TNR, GTV, HV, patients' age, or Karnofsky performance scale (KPS) was significantly correlated with PSF or OS. The hMTV and hTLG were found to be independent factors affecting PFS and OS on multivariate analysis. CONCLUSIONS: We introduced hMTV and hTLG using FDG and FMISO PET to define metabolically active hypoxic volume. Univariate and multivariate analyses demonstrated that both hMTV and hTLG are significant predictors for PFS and OS in glioblastoma patients.
  • MRI and 18F-FDG PET/CT of Laryngeal Cartilaginous Tumor.
    Junichi Nakagawa, Osamu Manabe, Takatsugu Mizumachi, Hiromi Kanno-Okada, Kanako C Hatanaka, Tomoko Mitsuhashi, Noriko Oyama-Manabe, Kenji Hirata, Nagara Tamaki
    Clinical nuclear medicine, 42, 3, e157-e160, e160, 2017年03月, ［査読有り］, ［国際誌］
    英語, Cartilaginous tumors of the larynx are uncommon neoplasms that sometimes mimic laryngeal cancers. There has been no report of F-FDG PET/CT for the evaluation of laryngeal cartilaginous tumors. We reported 3 cases of laryngeal cartilaginous tumors with the image findings, including CT, FDG PET/CT, and MRI and reviewed literatures. We concluded that the combination of a very high-signal mass on T2-weighted magnetic resonance images and lower FDG uptake might be diagnostic image characteristics for distinguishing laryngeal cartilaginous tumor from laryngeal cancer.
  • I-123 iomazenil single photon emission computed tomography for detecting loss of neuronal integrity in patients with traumatic brain injury
    Kagari Abiko, Katsunori Ikoma, Tohru Shiga, Chietsugu Katoh, Kenji Hirata, Yuji Kuge, Kentaro Kobayashi, Nagara Tamaki
    EJNMMI RESEARCH, 7, 1, 28, 2017年03月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Cardiac fibroma with high 18F-FDG uptake mimicking malignant tumor.
    Atsuro Masuda, Osamu Manabe, Noriko Oyama-Manabe, Masanao Naya, Masahiko Obara, Mamoru Sakakibara, Kenji Hirata, Satoshi Yamada, Tomoaki Naka, Hiroyuki Tsutsui, Nagara Tamaki
    Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology, 24, 1, 323, 324, 2017年02月, ［査読有り］, ［国際誌］
    英語
  • 18F-fluoromisonidazole (FMISO) PET may have the potential to detect cardiac sarcoidosis.
    Osamu Manabe, Kenji Hirata, Okamoto Shozo, Tohru Shiga, Yuko Uchiyama, Kentaro Kobayashi, Shiro Watanabe, Takuya Toyonaga, Hisaya Kikuchi, Noriko Oyama-Manabe, Nagara Tamaki
    Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology, 24, 1, 329, 331, 2017年02月, ［査読有り］, ［国際誌］
    英語, 18F-fluoromisonidazole (FMISO) is a positron emission tomography (PET) tracer that accumulates in hypoxic tissues. We here present a case of suspected cardiac sarcoidosis which was detected with increased FMISO uptake.
  • Change in F-18-Fluoromisonidazole PET Is an Early Predictor of the Prognosis in the Patients with Recurrent High-Grade Glioma Receiving Bevacizumab Treatment
    Shigeru Yamaguchi, Kenji Hirata, Takuya Toyonaga, Kentaro Kobayashi, Yukitomo Ishi, Hiroaki Motegi, Hiroyuki Kobayashi, Tohru Shiga, Nagara Tamaki, Shunsuke Terasaka, Kiyohiro Houkin
    PLOS ONE, 11, 12, e0167917, 2016年12月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • The reoxygenation of hypoxia and the reduction of glucose metabolism in head and neck cancer by fractionated radiotherapy with intensity-modulated radiation therapy
    Shozo Okamoto, Tohru Shiga, Koichi Yasuda, Shiro Watanabe, Kenji Hirata, Ken-ichi Nishijima, Keiichi Magota, Katsuhiko Kasai, Rikiya Onimaru, Kazuhiko Tuchiya, Yuji Kuge, Hiroki Shirato, Nagara Tamaki
    EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, 43, 12, 2147, 2154, 2016年11月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Glucose Metabolism and Its Complicated Relationship with Tumor Growth and Perfusion in Head and Neck Squamous Cell Carcinoma
    Noriyuki Fujima, Tomohiro Sakashita, Akihiro Homma, Kenji Hirata, Tohru Shiga, Kohsuke Kudo, Hiroki Shirato
    PLOS ONE, 11, 11, e0166236, 2016年11月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • The usefulness of (18)F-FDG PET/CT for assessing methotrexate-associated lymphoproliferative disorder (MTX-LPD).
    Shiro Watanabe, Osamu Manabe, Kenji Hirata, Noriko Oyama-Manabe, Naoya Hattori, Yasuka Kikuchi, Kentaro Kobayashi, Takuya Toyonaga, Nagara Tamaki
    BMC cancer, 16, 635, 635, 2016年08月15日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Methotrexate-associated lymphoproliferative disorder (MTX-LPD) is a benign lymphoid proliferation or malignant lymphoma in patients who have been treated with MTX. MTX withdrawal and observation for a short period should be considered in the initial management of patients who develop LPD while on MTX therapy. Here we evaluated the diagnostic accuracy and predictive value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for MTX-LPD. METHODS: We retrospectively investigated the cases of 15 patients clinically suspected of having MTX-LPD. A total of 324 anatomic regions (207 nodal and 117 extranodal regions) were assessed by (18)F-FDG PET/CT and by multi-detector row CT (MDCT). Each anatomic region was classified as either malignant or benign. The uptake of (18)F-FDG was assessed semi-quantitatively with the standardized uptake value maximum (SUVmax), the whole-body metabolic tumor volume (WBMTV), and the whole-body total lesion glycolysis (WBTLG) in order to investigate predictive factors of spontaneous regression after the withdrawal of MTX. RESULTS: MTX-LPD lesions were observed in 92/324 (28.4 %) regions. (18)F-FDG PET/CT showed 90.2 % sensitivity, 97.4 % specificity, and 95.4 % accuracy, values which were significantly higher than those of MDCT (59.8, 94.8, and 84.9 %, respectively. p < 0.002). After the withdrawal of MTX, 9/15 patients (60.0 %) achieved complete response (CR). The SUVmax, WBMTV and WBTLG values of the CR patients were 9.2 (range 2.8-47.1), 44.3 (range 0-362.6) ml, 181.8 (range 0-2180.9) ml, respectively, which were not significantly different from those of the non-CR patients: 10.6 (range 0-24.9), 15.7 (range 0-250.1) ml, and 97.4 (range 0-1052.1) ml. CONCLUSIONS: Although (18)F-FDG PET/CT was a useful tool to detect MTX-LPD lesions, none of the (18)F-FDG PET parameters before the withdrawal of MTX could be used to predict CR after the withdrawal of MTX.
  • Tumor hypoxia: a new PET imaging biomarker in clinical oncology
    Nagara Tamaki, Kenji Hirata
    INTERNATIONAL JOURNAL OF CLINICAL ONCOLOGY, 21, 4, 619, 625, 2016年08月, ［査読有り］
    英語
  • Reproducibility and uptake time dependency of volume-based parameters on FDG-PET for lung cancer
    Tomoka Kitao, Kenji Hirata, Katsumi Shima, Takashi Hayashi, Mitsunori Sekizawa, Toshiki Takei, Wataru Ichimura, Masao Harada, Keishi Kondo, Nagara Tamaki
    BMC CANCER, 16, 576, 2016年08月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • (18)F-fluoromisonidazole positron emission tomography can predict pathological necrosis of brain tumors.
    Takuya Toyonaga, Kenji Hirata, Shigeru Yamaguchi, Kanako C Hatanaka, Sayaka Yuzawa, Osamu Manabe, Kentaro Kobayashi, Shiro Watanabe, Tohru Shiga, Shunsuke Terasaka, Hiroyuki Kobayashi, Yuji Kuge, Nagara Tamaki
    European journal of nuclear medicine and molecular imaging, 43, 8, 1469, 76, 2016年07月, ［査読有り］, ［国際誌］
    英語, PURPOSE: Tumor necrosis is one of the indicators of tumor aggressiveness. (18)F-fluoromisonidazole (FMISO) is the most widely used positron emission tomography (PET) tracer to evaluate severe hypoxia in vivo. Because severe hypoxia causes necrosis, we hypothesized that intratumoral necrosis can be detected by FMISO PET in brain tumors regardless of their histopathology. We applied FMISO PET to various types of brain tumors before tumor resection and evaluated the correlation between histopathological necrosis and FMISO uptake. METHODS: This study included 59 brain tumor patients who underwent FMISO PET/computed tomography before any treatments. According to the pathological diagnosis, the brain tumors were divided into three groups: astrocytomas (group 1), neuroepithelial tumors except for astrocytomas (group 2), and others (group 3). Two experienced neuropathologists evaluated the presence of necrosis in consensus. FMISO uptake in the tumor was evaluated visually and semi-quantitatively using the tumor-to-normal cerebellum ratio (TNR). RESULTS: In visual analyses, 26/27 cases in the FMISO-positive group presented with necrosis, whereas 28/32 cases in the FMISO-negative group did not show necrosis. Mean TNRs with and without necrosis were 3.49 ± 0.97 and 1.43 ± 0.42 (p < 0.00001) in group 1, 2.91 ± 0.83 and 1.44 ± 0.20 (p < 0.005) in group 2, and 2.63 ± 1.16 and 1.35 ± 0.23 (p < 0.05) in group 3, respectively. Using a cut-off value of TNR = 1.67, which was calculated by normal reference regions of interest, we could predict necrosis with sensitivity, specificity, and accuracy of 96.7, 93.1, and 94.9 %, respectively. CONCLUSIONS: FMISO uptake within the lesion indicated the presence of histological micro-necrosis. When we used a TNR of 1.67 as the cut-off value, intratumoral micro-necrosis was sufficiently predictable. Because the presence of necrosis implies a poor prognosis, our results suggest that FMISO PET could provide important information for treatment decisions or surgical strategies of any type of brain tumor.
  • Use of convolutional neural network as the first step of fully automated tumor detection on 11C-methionine brain PET
    Hirata Kenji, Takeuchi Wataru, Yamaguchi Shigeru, Kobayashi Hiroyuki, Terasaka Shunsuke, Toyonaga Takuya, Watanabe Shiro, Kobayashi Kentaro, Manabe Osamu, Kobashi Keiji, Shiga Tohru, Tamaki Nagara
    JOURNAL OF NUCLEAR MEDICINE, 57, 2016年05月01日, ［査読有り］
  • Steroid therapy affects the cardiac metabolic shift and requires the careful attention in evaluation of the cardiac sarcoidosis with FDG PET/CT
    Manabe Osamu, Yoshinaga Keiichiro, Ohira Hiroshi, Oyama-Manabe Noriko, Tsujino Ichizo, Hirata Kenji, Kikuchi Hisaya, Nishimura Masaharu, Tamaki Nagara
    JOURNAL OF NUCLEAR MEDICINE, 57, 2016年05月01日, ［査読有り］
  • The effects of 18-h fasting with low-carbohydrate diet preparation on suppressed physiological myocardial (18)F-fluorodeoxyglucose (FDG) uptake and possible minimal effects of unfractionated heparin use in patients with suspected cardiac involvement sarcoidosis.
    Osamu Manabe, Keiichiro Yoshinaga, Hiroshi Ohira, Atsuro Masuda, Takahiro Sato, Ichizo Tsujino, Asuka Yamada, Noriko Oyama-Manabe, Kenji Hirata, Masaharu Nishimura, Nagara Tamaki
    Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology, 23, 2, 244, 52, 2016年04月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: (18)F-fluorodeoxyglucose (FDG) PET plays an important role in the detection of cardiac involvement sarcoidosis (CS). However, diffuse left ventricle (LV) wall uptake sometimes makes it difficult to distinguish between positive uptake and physiological uptake. The aims of this study were to evaluate the effects of 18-h fasting with low-carbohydrate diet (LCD) vs a minimum of 6-h fasting preparations on diffuse LV FDG uptake and free fatty acid (FFA) levels in patients with suspected CS. METHODS: Eighty-two patients with suspected CS were divided into 2 preparation protocols: one with a minimum 6-h fast without LCD preparation (group A, n = 58) and the other with a minimum 18-h fast with LCD preparation (group B, n = 24). All patients also received intravenous unfractionated heparin (UFH; 50 IU/kg) before the injection of FDG. RESULTS: Group A showed a higher percentage of diffuse LV uptake than did group B (27.6 vs 0.0%, P = .0041). Group B showed higher FFA levels (1159.1  ±  393.0, 650.5  ±  310.9 μEq/L, P < .0001) than did group A. Patients with diffuse LV uptake (n = 16) showed lower FFA levels than did other patients (n = 66) (432.1  ±  296.1, 888.4  ±  381.4 μEq/L, P < .0001). UFH administration significantly increased FFAs in both groups, even in the patients with diffuse LV FDG uptake. CONCLUSIONS: The 18-h fast with LCD preparation significantly reduced diffuse LV uptake and increased FFA levels. In particular, the FFA level was significantly lower in patients with LV diffuse uptake than in patients without LV diffuse uptake. Acutely increasing plasma FFA through the use of UFH may not have a significant role in reducing physiological LV FDG uptake.
  • uPAR as a Glioma Imaging Target
    Kenji Hirata, Nagara Tamaki
    JOURNAL OF NUCLEAR MEDICINE, 57, 2, 169, 170, 2016年02月, ［査読有り］
    英語
  • 中咽頭癌に合併し多発骨転移との鑑別が困難であった急性リンパ性白血病の一例　　　　　　　　　　　　　　　
    渡邊 史郎, 真鍋 治, 平田 健司, 菊地 恒矢, 牧野 俊一, 豊永 拓哉, 小林 健太郎, 内山 裕子, 志賀 哲, 加納 里志, 玉木 長良
    核医学, 53, 1, 507, 507, (一社)日本核医学会, 2016年02月
    日本語
  • Feasibility of Quantifying Myocardial Blood Flow with a Shorter Acquisition Time Using 15O-H2O PET
    Maruo Ayaka, Manabe Osamu, Yoshinaga Keiichiro, Naya Masanao, Tomiyama Yuuki, Oyama-Manabe Noriko, Hirata Kenji, Magota Keiichi, Tsutsui Hiroyuki, Katoh Chietsugu, Tamaki Nagara
    Annals of Nuclear Cardiology, 2, 1, 30, 37, 日本心臓核医学会, 2016年
    英語, Purpose: The quantification of coronary flow reserve (CFR) calculated as the ratio of the myocardial blood flow (MBF) during adenosine triphosphate (ATP) stress to MBF at rest is a useful method for evaluating the functional severity of coronary artery disease (CAD) using 15O-H2O positron emission tomography (PET). The shorter acquisition time may reduce dyspnea and other side effects of ATP stress and may also reduce the effect of body movements during data acquisition. However, the impact of the shorter data acquisition time on the accuracy of MBF quantification has not been studied. In this retrospective study, we evaluated the accuracy of the MBF and CFR values obtained with shorter scan times using 15O-H2O PET.
    Methods: Thirty patients suspected of having CAD (22 males, 8 females; age 56.5±8.8 yrs) and 17 healthy controls (17 males; age 27.7±6.2 yrs) underwent PET during rest and PET with ATP stress dynamic 15O-H2O. The MBF was estimated with a one-tissue compartment model analysis. MBF and CFR values were calculated using the first 2-min and 3-min PET data of 15O-H2O as shorter data acquisitions. These data were compared to the standard 6-min PET acquisition data.
    Results: With the use of the 3-min data, the regions of interest (ROIs) in the left ventricular (LV) chamber and myocardium could be set for all of the subjects. The intraclass correlation coefficients (ICCs) between the 3-min data and 6-min data of the rest MBF, stress MBF and CFR were 0.869, 0.870, and 0.819 in the patients, and 0.912, 0.910, and 0.930 in the controls. The 3-min CFR data showed a significant difference between the patients and controls (2.22±1.02 vs. 4.02±1.50, p<0.01), as did the 6-min data (2.19±0.92 vs. 4.16±1.39, p<0.01). However, the CFR based on 2-min data did not show a significant difference (1.96±1.66 vs. 2.73±1.03, p=0.088). Using a receiver operating characteristic (ROC) analysis, we observed that both the 3-min and 6-min CFR data could be used to separate the CAD patients and controls.
    Conclusions: A 3-min, but not 2-min, scan with 15O-H2O PET can be used for the quantitative evaluation of MBF and CFR.
  • Positron emission tomography-computed tomography can be useful in the early detection of metastases in primary mucinous carcinoma of the skin on the head and neck
    S. Kitamura, H. Hata, Y. Inamura, K. Imafuku, T. Sakashita, K. Hirata, H. Shimizu
    British Journal of Dermatology, 173, 5, 1263, 1265, Blackwell Publishing Ltd, 2015年11月01日, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Quantification of myocardial blood flow with dynamic perfusion 3.0 Tesla MRI: Validation with (15) O-water PET.
    Yuuki Tomiyama, Osamu Manabe, Noriko Oyama-Manabe, Masanao Naya, Hiroyuki Sugimori, Kenji Hirata, Yuki Mori, Hiroyuki Tsutsui, Kohsuke Kudo, Nagara Tamaki, Chietsugu Katoh
    Journal of magnetic resonance imaging : JMRI, 42, 3, 754, 62, 2015年09月, ［査読有り］, ［国際誌］
    英語, BACKGROUND: To develop and validate a method for quantifying myocardial blood flow (MBF) using dynamic perfusion magnetic resonance imaging (MBFMRI ) at 3.0 Tesla (T) and compare the findings with those of (15) O-water positron emission tomography (MBFPET ). METHODS: Twenty healthy male volunteers underwent magnetic resonance imaging (MRI) and (15) O-water positron emission tomography (PET) at rest and during adenosine triphosphate infusion. The single-tissue compartment model was used to estimate the inflow rate constant (K1). We estimated the extraction fraction of Gd-DTPA using K1 and MBF values obtained from (15) O-water PET for the first 10 subjects. For validation, we calculated MBFMRI values for the remaining 10 subjects and compared them with the MBFPET values. In addition, we compared MBFMRI values of 10 patients with coronary artery disease with those of healthy subjects. RESULTS: The mean resting and stress MBFMRI values were 0.76 ± 0.10 and 3.04 ± 0.82 mL/min/g, respectively, and showed excellent correlation with the mean MBFPET values (r = 0.96, P < 0.01). The mean stress MBFMRI value was significantly lower for the patients (1.92 ± 0.37) than for the healthy subjects (P < 0.001). CONCLUSION: The use of dynamic perfusion MRI at 3T is useful for estimating MBF and can be applied for patients with coronary artery disease.
  • Metabolic Activity of Red Nucleus and Its Correlation with Cerebral Cortex and Cerebellum: A Study Using a High-Resolution Semiconductor PET System.
    Kenji Hirata, Naoya Hattori, Wataru Takeuchi, Tohru Shiga, Yuichi Morimoto, Kikuo Umegaki, Kentaro Kobayashi, Osamu Manabe, Shozo Okamoto, Nagara Tamaki
    Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 56, 8, 1206, 11, 2015年08月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, UNLABELLED: The red nucleus (RN) is a pair of small gray matter structures located in the midbrain and involved in muscle movement and cognitive functions. This retrospective study aimed to investigate the metabolism of human RN and its correlation to other brain regions. METHODS: We developed a high-resolution semiconductor PET system to image small brain structures. Twenty patients without neurologic disorders underwent whole-brain scanning after injection of 400 MBq of (18)F-FDG. The individual brain (18)F-FDG PET images were spatially normalized to generate a surface projection map using a 3-dimensional stereotactic surface projection technique. The correlation between the RN and each voxel on the cerebral and cerebellar cortices was estimated with Pearson product-moment correlation analysis. RESULTS: Both right and left RNs were visualized with higher uptake than that in the background midbrain. The maximum standardized uptake values of RN were 7.64 ± 1.92; these were higher than the values for the dentate nucleus but lower than those for the caudate nucleus, putamen, and thalamus. The voxel-by-voxel analysis demonstrated that the right RN was correlated more with ipsilateral association cortices than contralateral cortices, whereas the left RN was equally correlated with ipsilateral and contralateral cortices. The left RN showed a stronger correlation with the motor cortices and cerebellum than the right RN did. CONCLUSION: Although nonspecific background activity around RNs might have influenced the correlation patterns, these metabolic relationships suggested that RN cooperates with association cortices and limbic areas to conduct higher brain functions.
  • Primary mucinous cell carcinoma of the skinのリンパ節転移に関するPET-CT所見の検討　　　　　　　　　　　　　　　
    北村 真也, 秦 洋郎, 稲村 有香, 今福 恵輔, 坂下 智博, 平田 健司, 清水 宏
    日本皮膚科学会雑誌, 125, 8, 1601, 1602, (公社)日本皮膚科学会, 2015年07月
    日本語
  • Improvement of cerebral hypometabolism after resection of radiation-induced necrotic lesion in a patient with cerebral arteriovenous malformation.
    Yae Harada, Kenji Hirata, Naoki Nakayama, Shigeru Yamaguchi, Michiharu Yoshida, Shunsuke Onodera, Osamu Manabe, Tohru Shiga, Satoshi Terae, Hiroki Shirato, Nagara Tamaki
    Acta radiologica open, 4, 6, 2058460115584112, 2058460115584112, 2015年06月, ［査読有り］, ［国際誌］
    英語, A 55-year-old woman underwent radiosurgery for a left cerebral hemisphere arteriovenous malformation (AVM) and developed radiation-induced necrosis causing a massive edema in the surrounding brain tissues. Despite various therapies, the edema expanded to the ipsilateral hemisphere and induced neurological symptoms. The radiation-induced necrotic lesion was surgically removed 4 years after radiosurgery. While the preoperative FDG PET revealed severe hypometabolism in the left cerebrum, the necrotomy significantly ameliorated the brain edema, glucose metabolism (postoperative FDG PET), and symptoms. This case indicates that radiation necrosis-induced neurological deficits may be associated with brain edema and hypometabolism, which could be reversed by appropriate necrotomy.
  • Prognostic value of volume-based measurements on (11)C-methionine PET in glioma patients.
    Kentaro Kobayashi, Kenji Hirata, Shigeru Yamaguchi, Osamu Manabe, Shunsuke Terasaka, Hiroyuki Kobayashi, Tohru Shiga, Naoya Hattori, Shinya Tanaka, Yuji Kuge, Nagara Tamaki
    European journal of nuclear medicine and molecular imaging, 42, 7, 1071, 80, 2015年06月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: (11)C-methionine (MET) PET is an established diagnostic tool for glioma. Studies have suggested that MET uptake intensity in the tumor is a useful index for predicting patient outcome. Because MET uptake is known to reflect tumor expansion more accurately than MRI, we aimed to elucidate the association between volume-based tumor measurements and patient prognosis. METHODS: The study population comprised 52 patients with newly diagnosed glioma who underwent PET scanning 20 min after injection of 370 MBq MET. The tumor was contoured using a threshold of 1.3 times the activity of the contralateral normal cortex. Metabolic tumor volume (MTV) was defined as the total volume within the boundary. Total lesion methionine uptake (TLMU) was defined as MTV times the mean standardized uptake value (SUVmean) within the boundary. The tumor-to-normal ratio (TNR), calculated as the maximum standardized uptake value (SUVmax) divided by the contralateral reference value, was also recorded. All patients underwent surgery (biopsy or tumor resection) targeting the tissue with high MET uptake. The Kaplan-Meier method was used to estimate the predictive value of each measurement. RESULTS: Grade II tumor was diagnosed in 12 patients (3 diffuse astrocytoma, 2 oligodendroglioma, and 7 oligoastrocytoma), grade III in 18 patients (8 anaplastic astrocytoma, 6 anaplastic oligodendroglioma, and 4 anaplastic oligoastrocytoma), and grade IV in 22 patients (all glioblastoma). TNR, MTV and TLMU were 3.1 ± 1.2, 51.6 ± 49.9 ml and 147.7 ± 153.3 ml, respectively. None of the three measurements was able to categorize the glioma patients in terms of survival when all patients were analyzed. However, when only patients with astrocytic tumor (N = 33) were analyzed (i.e., when those with oligodendroglial components were excluded), MTV and TLMU successfully predicted patient outcome with higher values associated with a poorer prognosis (P < 0.05 and P < 0.01, respectively), while the predictive ability of TNR did not reach statistical significance (P = NS). CONCLUSION: MTV and TLMU may be useful for predicting outcome in patients with astrocytic tumor.
  • Oligodendroglial component complicates the prediction of tumour grading with metabolic imaging.
    Osamu Manabe, Naoya Hattori, Shigeru Yamaguchi, Kenji Hirata, Kentaro Kobayashi, Shunsuke Terasaka, Hiroyuki Kobayashi, Hiroaki Motegi, Tohru Shiga, Keiichi Magota, Noriko Oyama-Manabe, Ken-ichi Nishijima, Yuji Kuge, Nagara Tamaki
    European journal of nuclear medicine and molecular imaging, 42, 6, 896, 904, 2015年05月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: Previous radiological investigations have generally shown the superiority of metabolic imaging in distinguishing high-grade from low-grade glioma, but the presence of an oligodendroglial component may affect the diagnostic accuracy. We investigated the diagnostic accuracy of PET imaging using (11)C-methionine (MET) and (18)F-fluorodeoxyglucose (FDG) in distinguishing high-grade from low-grade glioma, in correlation with the oligodendroglial component. METHODS: The study population comprised adult patients who underwent preoperative PET imaging using both MET and FDG within 1 week and successful excision of the tumour tissue, which confirmed WHO grade II-IV glioma. We examined the tumour metabolic activity in terms of lesion-to-normal uptake ratios (L/N ratio) in both MET PET and FDG PET images. We assessed the correlation between the imaging results and the histological findings to determine the diagnostic accuracy of receiver operating characteristics (ROC) analysis in detecting high-grade tumours. RESULTS: We studied 46 patients with glioma (13 low-grade and 33 high-grade), including 26 with an oligodendroglial components. The L/N ratios of the PET images showed significantly higher metabolic activities in high-grade gliomas than in low-grade gliomas for both MET (4.29 ± 1.22 and 2.36 ± 0.72, respectively; p < 0.0001) and FDG (1.72 ± 0.91 and 0.77 ± 0.26, respectively; p = 0.0007) images, although significant overlaps in L/N ratio were observed between high-grade and low-grade gliomas. Excluding the 26 patents with an oligodendroglial component improved the separation for both MET (4.62 ± 1.14 vs. 2.16 ± 0.63; p < 0.001) and FDG (1.76 ± 0.87 vs. 0.71 ± 0.14; p < 0.05) images. The ROC analyses demonstrated the clinical utility of the metabolic radiotracers in distinguishing high-grade from low-grade gliomas, showing similar AUC values for MET (0.91) and FDG (0.92). Excluding the 26 patents with an oligodendroglial component also further improved the diagnostic accuracy for both MET (AUC 0.98), and FDG (AUC 1.00) images. The metabolic radiotracers were significantly correlated with the MIB-1 labelling index (R = 0.52, p < 0.05 for MET; R = 0.52, p < 0.05, for FDG) only in gliomas without an oligodendroglial component. CONCLUSION: For better characterization of gliomas and for risk assessment, the results of metabolic PET imaging should be revised after obtaining the pathological report, because oligodendroglial differentiation may positively influence the substrate metabolism and thus complicated the preoperative evaluation.
  • FDG PET/CT diagnostic criteria may need adjustment based on MRI to estimate the presurgical risk of extrapelvic infiltration in patients with uterine endometrial cancer.
    Satoko Sudo, Naoya Hattori, Osamu Manabe, Fumi Kato, Rie Mimura, Keiichi Magota, Hiroyuki Sugimori, Kenji Hirata, Noriaki Sakuragi, Nagara Tamaki
    European journal of nuclear medicine and molecular imaging, 42, 5, 676, 84, 2015年04月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, PURPOSE: The staging of endometrial cancer requires surgery which carries the risk of morbidity. FDG PET/CT combined with anatomical imaging may reduce the number of unnecessary lymphadenectomies by demonstrating the risk of extrapelvic infiltration. The purpose of this study was to optimize FDG PET/CT diagnostic criteria for risk assessment in endometrial cancer after first-line risk triage with MRI. METHODS: The study population comprised 37 patients who underwent curative surgery for the treatment of endometrial cancer. First, the risk of extrapelvic infiltration was triaged using MRI. Second, multiple glucose metabolic profiles of the primary lesion were assessed with FDG PET/CT, and these were correlated with the histopathological risk of extrapelvic infiltration including lymphovascular space invasion (LVSI) and high-grade malignancy (grades 2 and 3). The results of histological correlation were used to adjust FDG PET/CT diagnostic criteria. RESULTS: Presurgical assessment using MRI was positive for deep (>50 %) myometrial invasion in 17 patients. The optimal FDG PET/CT diagnostic criteria vary depending on the results of MRI. Specifically, SUVmax (≥16.0) was used to indicate LVSI risk with an overall diagnostic accuracy of 88.2 % in patients with MRI findings showing myometrial invasion. High-grade malignancy did not correlate with any of metabolic profiles in this patient group. In the remaining patients without myometrial invasion, lesion glycolysis (LG) or metabolic volume were better indicators of LVSI than SUVmax with the same diagnostic accuracy of 80.0 %. In addition, LG (≥26.9) predicted high-grade malignancy with an accuracy of 72.2 %. Using the optimized cut-off criteria for LVSI, glucose metabolic profiling of primary lesions correctly predicted lymph node metastasis with an accuracy of 73.0 %, which was comparable with the accuracy of visual assessment for lymph node metastasis using MRI and FDG PET/CT. CONCLUSION: FDG PET/CT diagnostic criteria may need adjustment based on the anatomical information provided by MRI. The optimized criteria can predict the risk of pathology-proven LVSI correctly in 83.8 % of patients before surgery, and thus would improve presurgical treatment planning.
  • Combined use of 18 F-FDG PET and corticosteroid for diagnosis of deep-seated primary central nervous system lymphoma without histopathological confirmation
    Shigeru Yamaguchi, Kenji Hirata, Sadahiro Kaneko, Hiroyuki Kobayashi, Tohru Shiga, Kentaro Kobayashi, Rikiya Onimaru, Hiroki Shirato, Nagara Tamaki, Shunsuke Terasaka, Kiyohiro Houkin
    ACTA NEUROCHIRURGICA, 157, 2, 187, 194, 2015年02月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Postoperative assessment of hepatic asialoglycoprotein receptor function with Tc-99m GSA: the safety margin of resection size in living donor liver transplantation.
    Kentaro Kobayashi, Naoya Hattori, Osamu Manabe, Kenji Hirata, Keiichi Magota, Tsuyoshi Shimamura, Nagara Tamaki
    Annals of transplantation, 20, 51, 8, 2015年01月26日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, BACKGROUND: Living liver donation is associated with size-dependent complications. The resectable size and its safety margin should be defined for the safety of donors. The purpose of the present study was to determine if the current partial hepatectomies are done under the safety margin of the resectable size, by measuring asialoglycoprotein receptor (ASGPR) function of donor's remnant liver. MATERIAL AND METHODS: Seventy-four living donors (age 35±11 years) underwent Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (Tc-99m GSA) scintigraphy at postoperative week 1. We evaluated the scintigraphic results using established parameters of GSA uptake (LHL15) and its clearance from the blood pool (HH15). Based on the literature, we consider HH15 <0.55 to indicate normal ASGPR function, and 0.55£ HH15 <0.65 to indicate mild impairment. In terms of the hepatic uptake, we consider LHL15>0.93 to indicate normal ASGPR function, and 0.87< LHL15 £0.93 to indicate mild impairment. RESULTS: The average resected size was 337±170 mL, corresponding to 28±12% of the original donor's whole liver volume. No donors showed 0.65≤ HH15 or LHL15 <0.87, suggesting moderate or severely impaired ASGPR function. However, larger resection size (35-53%) was positively associated with higher HH15 values (R=0.53, p<0.001). In the range of HH15 (0.35-0.64) among present donors, higher HH15 values did not affect the regeneration volume (R=0.03, p=NS). CONCLUSIONS: Larger partial resection (≥35% of the original liver volume) may impair postsurgical ASGPR function, but smaller resection (<35%) was considered to be under the safety margin of the hepatectomy. Although mildly impaired postsurgical ASGPR function did not indicate poor prognosis, careful attention may be required for donors undergoing larger (³35%) partial resection.
  • Improved spillover correction model to quantify myocardial blood flow by 11C-acetate PET: comparison with 15O-H 2O PET.
    Yuki Mori, Osamu Manabe, Masanao Naya, Yuuki Tomiyama, Keiichiro Yoshinaga, Keiichi Magota, Noriko Oyama-Manabe, Kenji Hirata, Hiroyuki Tsutsui, Nagara Tamaki, Chietsugu Katoh
    Annals of nuclear medicine, 29, 1, 15, 20, 2015年01月, ［査読有り］, ［国内誌］
    英語, OBJECTIVE: (11)C-acetate has been applied for evaluation of myocardial oxidative metabolism and can simultaneously estimate myocardial blood flow (MBF). We developed a new method using two-parameter spillover correction to estimate regional MBF (rMBF) with (11)C-acetate PET in reference to MBF derived from (15)O-H2O PET. The usefulness of our new approach was evaluated compared to the conventional method using one-parameter spillover correction. METHODS: Sixty-three subjects were examined with (11)C-acetate and (15)O-H2O dynamic PET at rest. Inflow rate of (11)C-acetate (K1) was compared with MBF derived from (15)O-H2O PET. For the derivation, the relationship between K1 and MBF from (15)O-H2O was linked by the Renkin-Crone model in 20 subjects as a pilot group. One-parameter and two-parameter corrections were applied to suppress the spillover between left ventricular (LV) wall and LV cavity. Validation was set using the other 43 subjects' data. Finally, rMBFs were calculated using relational expression derived from the pilot-group data. RESULTS: The relationship between K1 and MBF derived from (15)O-H2O PET was approximated as K1 = [1-0.764 × exp(-1.001/MBF)] MBF from the pilot data using the two-parameter method. In the validation set, the correlation coefficient between rMBF from (11)C-acetate and (15)O-H2O demonstrated a significantly higher relationship with the two-parameter spillover correction method than the one-parameter spillover correction method (r = 0.730, 0.592, respectively, p < 0.05). CONCLUSION: In (11)C-acetate PET study, the new two-parameter spillover correction method dedicated more accurate and robust myocardial blood flow than the conventional one-parameter method.
  • Effects of Surgical Revascularization on Cerebral Oxygen Metabolism in Patients With Moyamoya Disease An O-15-Gas Positron Emission Tomographic Study
    Satoshi Kuroda, Daina Kashiwazaki, Kenji Hirata, Tohru Shiga, Kiyohiro Houkin, Nagara Tamaki
    STROKE, 45, 9, 2717, 2721, 2014年09月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Radiological images of keratocystoma: a rare tumor of the parotid gland.
    Hirata K, Fujima N, Mizumachi T, Bandarchi B, Roesler JM
    Acta radiologica short reports, 3, 8, 2047981614549497, 2047981614549497, 2014年09月, ［査読有り］, ［国際誌］
    英語, A 34-year-old man found a mildly tender preauricular mass. Ultrasonography revealed an anechoic mass in the superficial lobe of the parotid gland. Magnetic resonance imaging showed thin ring-like contrast enhancement and homogenously high intensity on T2-weighted images. The mass was resected due to its rapid growth. The cystic lesion contained keratine-like material and a stratified squamous epithelium without granular layers, which was consistent with keratocystoma.
  • The diagnostic role of (18)F-FDG PET for primary central nervous system lymphoma.
    Shigeru Yamaguchi, Kenji Hirata, Hiroyuki Kobayashi, Tohru Shiga, Osamu Manabe, Kentaro Kobayashi, Hiroaki Motegi, Shunsuke Terasaka, Kiyohiro Houkin
    Annals of nuclear medicine, 28, 7, 603, 9, 2014年08月, ［査読有り］, ［国内誌］
    英語, 研究論文（学術雑誌）, OBJECTIVE: (18)F-FDG PET has become one of the most important methods for studying malignant lymphoma, but its diagnostic role for primary central nervous system lymphoma (PCNSL) has not been established. The aim of this study was to determine the appropriate cut-off values of FDG uptake and to investigate how corticosteroid administration influences PCNSL. METHODS: We retrospectively reviewed 82 patients with contrast-enhanced brain tumors who underwent an FDG PET scan at onset, including 19 PCNSLs. FDG uptake of the lesion was assessed by the maximum standardized uptake value (SUVmax) and the ratio of tumor to normal contralateral cortex activity (T/N ratio). Receiver operating characteristic (ROC) curves were generated from the SUVmax and T/N ratios. To investigate the influence of corticosteroid application before a FDG PET scan, we evaluated the association between the FDG uptake of the lesion and the cumulative dose of corticosteroid administration on 13 PCNSL patients who had received steroid treatment before an FDG PET examination. RESULTS: The mean FDG SUVmax and T/N ratio of PCNSLs were 22.6 and 2.79, respectively, and these values were significantly higher than those of the other malignant brain tumors. ROC analysis indicated that the evaluation of FDG uptake using the T/N ratio was more reliable than the SUVmax with respect to the differential diagnosis. When PCNSL patients went without steroid application before FDG PET, the accuracy of the T/N ratio with a cut-off point of 2.0 was 91.1%, the sensitivity was 94.7%, and the specificity was 87.3%. Although there are no significant differences in the FDG T/N ratio for PCNSL patients with or without steroid treatment, a negative correlation was found between the T/N ratio and cumulative dose of corticosteroid before PET study (r = -0.71, p = 0.032). CONCLUSIONS: We concluded that the T/N ratio was superior to SUVmax for FDG uptake assessment as for distinguishing PCNSLs from other malignant brain tumors; the appropriate T/N ratio cut-off point was 2.0. In addition, FDG uptake could be influenced by cumulative doses of corticosteroid before a PET scan, and thus this fact should be taken into consideration when evaluating FDG PET for PCNSL diagnosis.
  • Evaluation of delineation of image details in semiconductor PET utilizing the normalized mutual information technique
    Naoki Kubo, Kenji Hirata, Kazuki Matsuzaki, Yuichi Morimoto, Wataru Takeuchi, Naoya Hattori, Tohru Shiga, Yuji Kuge, Nagara Tamaki
    NUCLEAR MEDICINE COMMUNICATIONS, 35, 6, 677, 682, 2014年06月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Clinical significance of STA-MCA double anastomosis for hemodynamic compromise in post-JET/COSS era
    Satoshi Kuroda, Masahito Kawabori, Kenji Hirata, Tohru Shiga, Daina Kashiwazaki, Kiyohiro Houkin, Nagara Tamaki
    ACTA NEUROCHIRURGICA, 156, 1, 77, 83, 2014年01月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • A semi-automated technique determining the liver standardized uptake value reference for tumor delineation in FDG PET-CT.
    Kenji Hirata, Kentaro Kobayashi, Koon-Pong Wong, Osamu Manabe, Andrew Surmak, Nagara Tamaki, Sung-Cheng Huang
    PloS one, 9, 8, e105682, 2014年, ［査読有り］, ［国際誌］
    英語, BACKGROUND: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) has been an essential modality in oncology. We propose a semi-automated algorithm to objectively determine liver standardized uptake value (SUV), which is used as a threshold for tumor delineation. METHODS: A large spherical volume of interest (VOI) was placed manually to roughly enclose the right lobe (RL) of the liver. For each voxel in this VOI, a coefficient of variation of voxel values (CVv) was calculated for neighboring voxels within a radius of d/2. The voxel with the minimum CVv was then selected, where a 30-mm spherical VOI was placed at that voxel in accordance with PERCIST criteria. Two nuclear medicine physicians independently defined 30-mm VOIs manually on 124 studies in 62 patients to generate the standard values, against which the results from the new method were compared. RESULTS: The semi-automated method was successful in determining the liver SUV that was consistent between the two physicians in all the studies (d = 80 mm). The liver SUV threshold (mean +3 SD within 30-mm VOI) determined by the new semi-automated method (3.12±0.61) was not statistically different from those determined by the manual method (Physician-1: 3.14±0.58, Physician-2: 3.15±0.58). The semi-automated method produced tumor volumes that were not statistically different from those by experts' manual operation. Furthermore, the volume change in the two sequential studies had no statistical difference between semi-automated and manual methods. CONCLUSIONS: Our semi-automated method could define the liver SUV robustly as the threshold value used for tumor volume measurements according to PERCIST. The method could avoid possible subjective bias of manual liver VOI placement and is thus expected to improve clinical performance of volume-based parameters for prediction of cancer treatment response.
  • Effective Surgical Revascularization Improves Cerebral Hemodynamics and Resolves Headache in Pediatric Moyamoya Disease
    Masahito Kawabori, Satoshi Kuroda, Naoki Nakayama, Kenji Hirata, Toru Shiga, Kiyohiro Houkin, Nagara Tamaki
    WORLD NEUROSURGERY, 80, 5, 612, 619, 2013年11月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Usefulness of FMISO-PET for Glioma Analysis
    Hiroyuki Kobayashi, Kenji Hirata, Shigeru Yamaguchi, Shunsuke Terasaka, Tohru Shiga, Kiyohiro Houkin
    NEUROLOGIA MEDICO-CHIRURGICA, 53, 11, 773, 778, 2013年11月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Assessment of early changes in H-3-fluorothymidine uptake after treatment with gefitinib in human tumor xenograft in comparison with Ki-67 and phospho-EGFR expression
    Songji Zhao, Yuji Kuge, Yan Zhao, Satoshi Takeuchi, Kenji Hirata, Toshiki Takei, Tohru Shiga, Hirotoshi Dosaka-Akita, Nagara Tamaki
    BMC CANCER, 13, 525, 2013年11月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • A series of noninvasive evaluations for bilateral adrenal tumor
    Kenji Hirata, Kouzou Kubo
    EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, 40, 7, 1119, 1119, 2013年07月, ［査読有り］
    英語
  • Brain Regions Associated With Cognitive Impairment in Patients With Parkinson Disease Quantitative Analysis of Cerebral Blood Flow Using I-123 Iodoamphetamine SPECT
    Naoya Hattori, Ichiro Yabe, Kenji Hirata, Tohru Shiga, Ken Sakushima, Sachiko Tsuji-Akimoto, Hidenao Sasaki, Nagara Tamaki
    CLINICAL NUCLEAR MEDICINE, 38, 5, 315, 320, 2013年05月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Diagnostic accuracy of lymph node metastasis depends on metabolic activity of the primary lesion in thoracic squamous esophageal cancer.
    Osamu Manabe, Naoya Hattori, Kenji Hirata, Kazuo Itoh, Masao Hosokawa, Hiroaki Takahashi, Noriko Oyama-Manabe, Nagara Tamaki
    Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 54, 5, 670, 6, 2013年05月, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, UNLABELLED: The metabolic activity of the primary tumor is an important variable in (18)F-FDG PET interpretation for presurgical staging, because this activity is likely to affect the possibility of detection of malignant involvement in lymph nodes (LNs). The purpose of this study was to reevaluate the diagnostic accuracy of (18)F-FDG PET/CT for the presurgical staging of esophageal squamous cell carcinoma (SCC) in correlation with the (18)F-FDG avidity of the primary lesions. METHODS: One hundred fifty-six patients (mean age ± SD, 61.4 ± 8.0 y) underwent (18)F-FDG PET/CT before surgical esophagectomy and LN dissection. LN metastasis was identified using the fusion of PET and CT images with increased (18)F-FDG uptake greater than the background activity of the adjacent structures. The results of the patients' (18)F-FDG PET/CT examinations for LN involvement were compared with the histopathologic results to investigate the diagnostic accuracy of (18)F-FDG PET/CT for tumor staging. In addition, we examined the correlation between the diagnostic accuracy of (18)F-FDG PET/CT for LN involvement and the (18)F-FDG avidity of the primary lesions, to investigate the effect of tumor aggressiveness on the diagnosis of LN metastasis. RESULTS: The diagnostic accuracy of (18)F-FDG PET/CT for LN metastasis showed a low sensitivity, ranging from 29.3% to 53.3%, whereas the specificity was higher than 89.8% in regional thoracic nodes and in remote areas of the cervical and abdominal regions. The (18)F-FDG uptake of the primary lesions positively correlated with that of the metastatic LNs in the thoracic field (R = 0.52, P < 0.05). As a result, our receiver-operating-characteristic analyses demonstrated an area under the curve value of 0.73, with the optimal cutoff value at a maximum standardized uptake value of 3.3 in patients with mid to high (18)F-FDG avidity in the primary lesions (maximum standardized uptake value ≥ 5). CONCLUSION: This study showed that the avidity of the primary esophageal SCCs affected the detectability of lymph nodal metastases. If primary lesions of esophageal SCC present with a low (18)F-FDG uptake, PET/CT may have a limited role for initial staging because of low sensitivity to detect lymph node metastases.
  • Validity of Dual MRI and F-18-FDG PET Imaging in Predicting Vulnerable and Inflamed Carotid Plaque
    Hisayasu Saito, Satoshi Kuroda, Kenji Hirata, Keiichi Magota, Tohru Shiga, Nagara Tamaki, Daisuke Yoshida, Satoshi Terae, Naoki Nakayama, Kiyohiro Houkin
    CEREBROVASCULAR DISEASES, 35, 4, 370, 377, 2013年, ［査読有り］
    英語, 研究論文（学術雑誌）
  • (11)C-Methionine positron emission tomography may monitor the activity of encephalitis.
    Kenji Hirata, Tohru Shiga, Noriyuki Fujima, Osamu Manabe, Reiko Usui, Yuji Kuge, Nagara Tamaki
    Acta radiologica (Stockholm, Sweden : 1987), 53, 10, 1155, 7, 2012年12月01日, ［査読有り］, ［国際誌］
    英語, 研究論文（学術雑誌）, Encephalitis is generally diagnosed by clinical symptoms, cerebrospinal fluid examination, and imaging studies including CT, magnetic resonance imaging (MRI), and perfusion single photon emission tomography (SPECT). However, the role of positron emission tomography (PET) in diagnosis of encephalitis remains unclear. A 49-year-old woman presenting with coma and elevated inflammatory reaction was diagnosed as having encephalitis according to slow activity on electroencephalogram, broad cortical lesion in MR fluid attenuated inversion recovery image, and increased blood flow demonstrated by SPECT. PET revealed increased accumulation of (11)C-methionine (MET) in the affected brain tissues. After the symptom had improved 2 months later, the accumulation of MET as well as the abnormal findings of MR imaging and SPECT was normalized. This case indicated that MET PET may monitor the activity of encephalitis.
  • Cardiac (18)F-FDG PET/CT with heparin detects infective vegetation in a patient with mechanical valve replacement.
    Alisa Klaipetch, Osamu Manabe, Noriko Oyama-Manabe, Satoru Chiba, Masanao Naya, Shiro Yamada, Kenji Hirata, Hiroyuki Tsutsui, Nagara Tamaki
    Clinical nuclear medicine, 37, 12, 1184, 5, 2012年12月, ［査読有り］, ［国際誌］
    英語, We report the usefulness of F-FDG PET/CT for the detection and therapy evaluation of the infective vegetation. A 64-year-old man with history of aortic valve replacement presented with 2 months of fever without identifiable cause. Echocardiogram showed no inflammation vegetation or abnormality of mechanical valve function. FDG PET/CT with 50 IU/kg IV heparin revealed focal uptakes near the mechanical aortic valve. After antibiotics therapy, fever was ameliorated, and FDG PET/CT findings showed markedly decreased uptake of the lesions. FDG PET/CT is a powerful tool to detect endocarditis even in patients with no anatomical abnormalities.
  • Predictors and Clinical Features of Postoperative Hyperperfusion after Surgical Revascularization for Moyamoya Disease A Serial Single Photon Emission CT/Positron Emission Tomography Study
    Haruto Uchino, Satoshi Kuroda, Kenji Hirata, Tohru Shiga, Kiyohiro Houkin, Nagara Tamaki
    STROKE, 43, 10, 2610, 2616, 2012年10月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Multimodality evaluation of cardiac paraganglioma.
    Osamu Manabe, Noriko Oyama-Manabe, Klaipetch Alisa, Kenji Hirata, Kazuo Itoh, Satoshi Terae, Yoshiro Matsui, Nagara Tamaki
    Clinical nuclear medicine, 37, 6, 599, 601, 2012年06月, ［査読有り］, ［国際誌］
    英語, We report 2 rare cases of primary cardiac paraganglioma demonstrated with multimodality imaging. Both a 46-year-old woman who presented with hypertension (case 1) and a 46-year-old woman without any symptoms (case 2) had mediastinal tumors depicted by CT and MRI. Both cases showed intense focal uptakes in the tumors with iodine-123-meta-iodobenzylguanidine SPECT. Case 2 also underwent 18F-FDG PET/CT and revealed a focal uptake. CT angiography detected the arterial feeder and venous drainages, information that was useful for the operation. After surgical removal, pathology confirmed primary cardiac paraganglioma in both cases. 18F-FDG PET/CT was also useful in ruling out residual or recurrent tumors.
  • Optimization of energy window setting of the semiconductor PET for clinical FDG studies
    Shiga Tohru, Takeuchi Wataru, Morimoto Yuichi, Kubo Naoki, Hirata Kenji, Kobashi Keiji, Hattori Naoya, Tamaki Nagara
    JOURNAL OF NUCLEAR MEDICINE, 53, 2012年05月01日, ［査読有り］
    英語
  • ¹⁸F-Fluoromisonidazole positron emission tomography may differentiate glioblastoma multiforme from less malignant gliomas.
    Hirata K, Terasaka S, Shiga T, Hattori N, Magota K, Kobayashi H, Yamaguchi S, Houkin K, Tanaka S, Kuge Y, Tamaki N
    European journal of nuclear medicine and molecular imaging, 39, 5, 760, 770, 2012年05月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Transient Crossed Cerebellar Diaschisis Due to Cerebral Hyperperfusion Following Surgical Revascularization for Moyamoya Disease -Case Report
    Masaaki Hokari, Satoshi Kuroda, Yusuke Simoda, Haruto Uchino, Kenji Hirata, Tohru Shiga, Naoki Nakayama, Kiyohiro Houkin, Nagara Tamaki
    NEUROLOGIA MEDICO-CHIRURGICA, 52, 5, 350, 353, 2012年05月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • FDG-PET findings of intraductal oncocytic papillary neoplasms of the pancreas: Two case reports
    Takashi Kato, Shuji Ikari, Kenji Hirata, Takuro Machida, Hideaki Nakamura, Takashi Meguro, Takayuki Morita, Toshiyuki Takahashi, Nagara Tamaki, Shoichi Horita
    Case Reports in Gastroenterology, 6, 2, 415, 424, 2012年05月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Writing errors in ALS related to loss of neuronal integrity in the anterior cingulate gyrus
    Ichiro Yabe, Sachiko Tsuji-Akimoto, Tohru Shiga, Shinsuke Hamada, Kenji Hirata, Mika Otsuki, Yuji Kuge, Nagara Tamaki, Hidenao Sasaki
    JOURNAL OF THE NEUROLOGICAL SCIENCES, 315, 1-2, 55, 59, 2012年04月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Reoxygenation of Glioblastoma Multiforme Treated with Fractionated Radiotherapy Concomitant with Temozolomide: Changes Defined by F-18-fluoromisonidazole Positron Emission Tomography: Two Case Reports
    Takuhito Narita, Hidefumi Aoyama, Kenji Hirata, Shunsuke Onodera, Tohru Shiga, Hiroyuki Kobayashi, Junichi Murata, Shunsuke Terasaka, Shinya Tanaka, Kiyohiro Houkin
    JAPANESE JOURNAL OF CLINICAL ONCOLOGY, 42, 2, 120, 123, 2012年02月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Blood Flow Metabolism Mismatch Triggers Postoperative Hyperperfusion after Carotid Endarterectomy: A Serial SPECT/PET Study
    Shimbo Daisuke, Kuroda Satoshi, Nakayama Naoki, Kazumata Ken, Hirata Kenji, Shiga Tohru, Houkin Kiyohiro, Tamaki Nagara
    CEREBROVASCULAR DISEASES, 34, 19, 2012年, ［査読有り］
  • A Pitfall of C-11 Methionine PET Cerebral Venous Infarction Mimicked a Glioma
    Yae Harada, Kenji Hirata, Hiroyuki Kobayashi, Reiko Usui, Tohru Shiga, Satoshi Terae, Hiroki Shirato, Nagara Tamaki
    CLINICAL NUCLEAR MEDICINE, 37, 1, 110, 111, 2012年01月, ［査読有り］
    英語
  • Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography May Predict the Outcome in Patients With Asymptomatic Mild Stenosis of Internal Carotid Artery-Case Report
    Hiroaki Motegi, Satoshi Kuroda, Naoki Nakayama, Kenji Hirata, Tohru Shiga, Nagara Tamaki
    NEUROLOGIA MEDICO-CHIRURGICA, 51, 10, 720, 723, 2011年10月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • FDG PET/CT in a Patient With Spontaneous Remission of Methotrexate-Associated Lymphoproliferative Disorders After Interruption of Methotrexate
    Rinnosuke Kuramoto, Kenji Hirata, Toshiki Takei, Nobuhiko Oridate, Seigo Suzuki, Yosuke Yamada, Masahiro Imamura, Nagara Tamaki
    CLINICAL NUCLEAR MEDICINE, 36, 7, 582, 583, 2011年07月, ［査読有り］
    英語
  • Optimization of energy window setting of the semiconductor PET for human FDG studies
    Shiga Tohru, Takeuchi Wataru, Kubo Naoki, Hirata Kenji, Hattori Naoya, Usui Reiko, Morimoto Yuichi, Kobashi Keiji, Umegaki Kikuo, Tamaki Nagara
    JOURNAL OF NUCLEAR MEDICINE, 52, 2011年05月01日, ［査読有り］
    英語
  • Gene and protein analysis of brain derived neurotrophic factor expression in relation to neurological recovery induced by an enriched environment in a rat stroke model
    Kenji Hirata, Yuji Kuge, Chiaki Yokota, Akina Harada, Koichi Kokame, Hiroyasu Inoue, Hidekazu Kawashima, Hiroko Hanzawa, Yuji Shono, Hideo Saji, Kazuo Minematsu, Nagara Tamaki
    NEUROSCIENCE LETTERS, 495, 3, 210, 215, 2011年05月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Validity of F-18-fluorodeoxyglucose PET in Identifying Inflamed and Vulnerable Carotid Plaque - A Radiological and Pathological Study
    Kuroda Satoshi, Maruichi Katsuhiko, Nakayama Naoki, Houkin Kiyohiro, Hirata Kenji, Shiga Tohru, Tamaki Nagara
    STROKE, 42, 3, E183, 2011年03月, ［査読有り］
  • Long-term smoking causes more advanced coronary endothelial dysfunction in middle-aged smokers compared to young smokers.
    Masanao Naya, Koichi Morita, Keiichiro Yoshinaga, Osamu Manabe, Daisuke Goto, Kenji Hirata, Chietsugu Katoh, Nagara Tamaki, Hiroyuki Tsutsui
    European journal of nuclear medicine and molecular imaging, 38, 3, 491, 8, 2011年03月, ［査読有り］, ［国際誌］
    英語, PURPOSE: Smoking cessation has been shown to normalize the coronary endothelial dysfunction in healthy young smokers. However, its effect has not been explored in middle-aged smokers with a longer history of smoking. Therefore, we compared the effects of smoking cessation on coronary vasomotor response between both young and middle-aged smokers and identified the predictor for its improvement. METHODS: This study investigated 14 young healthy smokers (age 25.2 ± 2.3 years), 13 middle-aged smokers (age 42.0 ± 6.5 years) and 10 non-smokers. Myocardial blood flow (MBF) was measured by using (15)O-water positron emission tomography (PET). RESULTS: At baseline, the ratio of MBF during the cold pressor test (CPT) to that at rest (MBF(CPT/rest)), the index of coronary endothelial function, was significantly decreased in both young and middle-aged smokers compared to non-smokers (1.24 ± 0.20 and 1.10 ± 0.39 vs 1.53 ± 0.18, p < 0.05 and p < 0.001, respectively). The ratio of MBF during adenosine triphosphate infusion to that at rest was significantly decreased in middle-aged smokers compared to young smokers and non-smokers (3.34 ± 1.52 vs 4.43 ± 0.92 and 4.69 ± 1.25, p < 0.05, respectively). MBF(CPT/rest) at 1 month after smoking cessation significantly increased in young smokers, but not in middle-aged smokers. By multivariate analysis, baseline serum malondialdehyde-modified low-density lipoprotein (MDA-LDL) was an independent predictor for the changes in MBF(CPT/rest) after smoking cessation (β = -0.45, p < 0.05). CONCLUSION: Coronary endothelial dysfunction was reversible by short-term smoking cessation in young smokers, but not in middle-aged smokers, which was associated with serum MDA-LDL levels. Long-term smoking exposure could lead to more advanced coronary endothelial dysfunction and atherosclerosis possibly via oxidative stress.
  • Gene expression associated with an enriched environment after transient focal ischemia
    Yuji Shono, Chiaki Yokota, Yuji Kuge, Shinsuke Kido, Akina Harada, Koichi Kokame, Hiroyasu Inoue, Mariko Hotta, Kenji Hirata, Hideo Saji, Nagara Tamaki, Kazuo Minematsu
    BRAIN RESEARCH, 1376, 60, 65, 2011年02月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Detection of histological anaplasia in gliomas with oligodendroglial components using positron emission tomography with F-18-FDG and C-11-methionine: report of two cases
    Shigeru Yamaguchi, Hiroyuki Kobayashi, Kenji Hirata, Tohru Shiga, Shinya Tanaka, Junichi Murata, Shunsuke Terasaka
    JOURNAL OF NEURO-ONCOLOGY, 101, 2, 335, 341, 2011年01月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Regional partition coefficient of water in patients with cerebrovascular disease and its effect on rCBF assessment
    Kenji Hirata, Naoya Hattori, Chietsugu Katoh, Tohru Shiga, Satoshi Kuroda, Naoki Kubo, Reiko Usui, Yuji Kuge, Nagara Tamaki
    NUCLEAR MEDICINE COMMUNICATIONS, 32, 1, 63, 70, 2011年01月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • 脳虚血・臨床・モヤモヤ病 もやもや病術後症例に対する追加脳血行再建術 その実際と脳循環代謝
    黒田 敏, 中山 若樹, 平田 健司, 志賀 哲, 玉木 長良, 宝金 清博
    脳循環代謝, 22, 1, 78, 78, (一社)日本脳循環代謝学会, 2010年11月
    日本語
  • Combined use of positron emission tomography with 18F- fluorodeoxyglucose and 11C-methionine for preoperative evaluation of gliomas
    Shigeru Yamaguchi, Shunsuke Terasaka, Hiroyuki Kobayashi, Takuhito Narita, Kenji Hirata, Satoshi Shiga, Reiko Usui, Shinya Tanaka, Kanako Kubota, Junichi Murata, Katsuyuki Asaoka
    Neurological Surgery, 38, 7, 621, 628, 2010年07月, ［査読有り］
    日本語, 研究論文（学術雑誌）
  • Therapeutic effects of acupuncture in patients with rheumatoid arthritis: a prospective study using F-18-FDG-PET
    Masami Sato, Masayuki Inubushi, Tohru Shiga, Kenji Hirata, Shozo Okamoto, Tomohito Kamibayashi, Kazuhide Tanimura, Nagara Tamaki
    ANNALS OF NUCLEAR MEDICINE, 23, 3, 311, 316, 2009年05月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Indolent dorsal midbrain tumor: new findings based on positron emission tomography
    Shigeru Yamaguchi, Shunsuke Terasaka, Hiroyuki Kobayashi, Tohru Shiga, Reiko Usui, Kenji Hirata, Kanako Kubota, Junichi Murata, Yoshinobu Iwasaki
    JOURNAL OF NEUROSURGERY-PEDIATRICS, 3, 4, 270, 275, 2009年04月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Radioiodine Therapy for Thyroid Cancer Depicted Uterine Leiomyoma
    Kenji Hirata, Tohru Shiga, Kanako C. Kubota, Shozo Okamoto, Tomohito Kamibayashi, Nagara Tamaki
    CLINICAL NUCLEAR MEDICINE, 34, 3, 180, 181, 2009年03月, ［査読有り］
    英語
  • A New PET Scanner with Semiconductor Detectors Enables Better Identification of Intratumoral Inhomogeneity
    Tohru Shiga, Yuichi Morimoto, Naoki Kubo, Norio Katoh, Chietsugu Katoh, Wataru Takeuchi, Reiko Usui, Kenji Hirata, Shinichi Kojima, Kikuo Umegaki, Hiroki Shirato, Nagara Tamaki
    JOURNAL OF NUCLEAR MEDICINE, 50, 1, 148, 155, 2009年01月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • 多発性骨髄腫における全身methionine‐PETの有用性:FDG‐PETとの比較
    鐘ケ江香久子, 岡本祥三, 平田健司, 上林倫史, 趙松吉, 真鍋治, 久下裕司, 玉木長良
    核医学, 45, 3, S221, S185, (一社)日本核医学会, 2008年
    英語, 研究論文（その他学術会議資料等）
  • Whole-body iodine-131 metaiodobenzylguanidine imaging for detection of bone metastases in patients with paraganglioma: comparison with bone scintigraphy
    Tetsuya Inoue, Keiichiro Yoshinaga, Koichi Morita, Tohru Shiga, Kakuko Kanegae, Kenji Hirata, Shozo Okamoto, Nagara Tamaki
    ANNALS OF NUCLEAR MEDICINE, 21, 5, 307, 310, 2007年07月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • Does lemon candy decrease salivary gland damage after radioiodine therapy for thyroid cancer?
    K Nakada, T Ishibashi, T Takei, K Hirata, K Shinohara, S Katoh, SJ Zhao, N Tamaki, Y Noguchi, S Noguchi
    JOURNAL OF NUCLEAR MEDICINE, 46, 2, 261, 266, 2005年02月, ［査読有り］
    英語, 研究論文（学術雑誌）
  • 晩発性皮膚ポルフィリン症の臨床および生化学的解析
    近藤雅雄, 堀江裕, 平田健司, 古山和道, 柘植光代, 藤田博美, 佐々茂, 浦田郡平
    ポルフィリン, 13, 3/4, 93, 104, ポルフィリン研究会事務局, 2004年12月
    日本語
  • Extremely rare association of HFE mutations with porphyria cutanea tarda in Japanese patients.
    K Furuyama, M Kondo, K Hirata, H Fujita, S Sassa
    Hepatology (Baltimore, Md.), 30, 6, 1532, 3, 1999年12月, ［国際誌］
    英語

その他活動・業績

書籍等出版物

講演・口頭発表等

  • 核医学～近未来核医学の向かう道-診断・治療の精度をあげる最新手法～ 核医学におけるAIの活用と課題　　　　　　　　　　　　　　　
    平田 健司, 杉森 博行, 藤間 憲幸, 豊永 拓哉, 工藤 與亮
    日本医学放射線学会秋季臨床大会抄録集, 2022年08月, (公社)日本医学放射線学会, 日本語
    2022年08月 - 2022年08月
  • Prediction of Amyloid-β Positivity Using QSM Images Based on Bootstrap Your Own Latent.
    Tsubasa Kunieda, Ren Togo, Noriko Nishioka, Yukie Shimizu, Shiro Watanabe, Kenji Hirata, Keisuke Maeda, Takahiro Ogawa 0001, Kohsuke Kudo, Miki Haseyama
    GCCE, 2022年
    2022年 - 2022年
  • 心臓サルコイドーシス患者における血清可溶性インターロイキン2レセプター高値は長期予後と関連する
    小林 雄太, 永井 利幸, 平田 健司, 常田 慧徳, 加藤 喜哉, 小森山 弘和, 神谷 究, 小西 崇夫, 佐藤 琢真, 表 和徳, 工藤 與亮, 今野 哲, 安斉 俊久
    日本サルコイドーシス/肉芽腫性疾患学会雑誌, 2021年10月, 日本サルコイドーシス, 日本語
    2021年10月 - 2021年10月
  • 【Nuclear Medicine Today 2021 キーワードから展望する核医学の技術開発と臨床応用】人工知能(AI)の研究開発の現状と将来展望 1)腫瘍核医学におけるAI利用の動向
    平田 健司, 藤間 憲幸, 杉森 博行, 工藤 與亮
    INNERVISION, 2021年09月, (株)インナービジョン, 日本語
    2021年09月 - 2021年09月
  • IgG4関連肺病変を背景に生じた非角化型扁平上皮癌の一例　　　　　　　　　　　　　　　
    大塚 拓也, 伊藤 祥太郎, 松本 宗人, 氏家 秀樹, 常田 慧徳, 平田 健司, 朝比奈 肇, 加賀 基知三, 松野 吉宏
    日本病理学会会誌, 2021年03月, (一社)日本病理学会, 日本語
    2021年03月 - 2021年03月
  • 待機時間2時間は充分か 顎骨SPECT定量解析における撮像待機時間の研究　　　　　　　　　　　　　　　
    秦 浩信, 下村 悟史, 今待 賢治, 舩山 恭祐, 浅香 卓哉, 佐藤 淳, 平田 健司, 松坂 方士, 盛 洋一, 南部 敏和, 北川 善政
    核医学, 2021年, (一社)日本核医学会, 日本語
    2021年 - 2021年
  • パーキンソン病における両側STN-DBS後の体重増加と刺激位置との関連についての検討　　　　　　　　　　　　　　　
    江口 克紀, 白井 慎一, 山崎 和義, 濱内 祝嗣, 松島 理明, 加納 崇裕, 笹森 徹, 平田 健司, 関 俊隆, 志賀 哲, 大槻 美佳, 寳金 清博, 佐々木 秀直, 矢部 一郎
    日本定位・機能神経外科学会プログラム・抄録集, 2020年12月, (一社)日本定位・機能神経外科学会, 日本語
    2020年12月 - 2020年12月
  • PET画像におけるDeep learningとその複合技術を用いた検出精度の検討
    河上 壮志, 杉森 博行, 平田 健司, 孫田 惠一, 加藤 千恵次
    核医学技術, 2020年10月, (NPO)日本核医学技術学会, 日本語
    2020年10月 - 2020年10月
  • Deep learningを用いたPET画像における病変や生理的集積の自動検出精度の検討
    河上 壮志, 平田 健司, 杉森 博行, 加藤 千恵次
    核医学技術, 2019年10月, (NPO)日本核医学技術学会, 日本語
    2019年10月 - 2019年10月
  • FDG PETのテクスチャ解析を用いた心臓サルコイドーシスの予後検討　　　　　　　　　　　　　　　
    真鍋 治, 平田 健司, 真鍋 徳子, 古家 翔, 小梁川 和宏, 大平 洋, 相川 忠夫, 納谷 昌直, 辻野 一三, 玉木 長良, 志賀 哲
    核医学, 2019年10月, (一社)日本核医学会, 英語
    2019年10月 - 2019年10月
  • 心臓サルコイドーシス評価のFDG-PET/CT撮像にヘパリン注射は必要か?　　　　　　　　　　　　　　　
    古家 翔, 真鍋 治, 大平 洋, 納谷 昌直, 相川 忠夫, 小梁川 和宏, 辻野 一三, 真鍋 徳子[大山], 平田 健司, 志賀 哲
    核医学, 2019年10月, (一社)日本核医学会, 日本語
    2019年10月 - 2019年10月
  • メルケル細胞癌におけるPET-CTのFDG集積に関する細胞学的検討　　　　　　　　　　　　　　　
    北村 真也, 柳 輝希, 高島 有香, 今福 恵輔, 秦 洋郎, 清水 宏, 平田 健司, 上原 治朗, 石田 雄大, 大塚 篤司
    日本皮膚科学会雑誌, 2019年03月, (公社)日本皮膚科学会, 日本語
    2019年03月 - 2019年03月
  • Extraction of regions related to cardiac sarcoidosis in polar map images
    Ren Togo, Takahiro Ogawa, Osamu Manabe, Kenji Hirata, Tohru Shiga, Miki Haseyama
    2019 IEEE 1st Global Conference on Life Sciences and Technologies, LifeTech 2019, 2019年03月
    2019年03月 - 2019年03月
  • 123I-FP-CITにおけるシミュレーションを用いたTexture解析のReproducibility評価　　　　　　　　　　　　　　　
    池本 裕貴, 大崎 洋充, 平田 健司, 上原 歩夏, 清水 賢, 野上 敬太, 柏倉 健一, 立石 宇貴秀
    核医学, 2018年11月, (一社)日本核医学会, 日本語
    2018年11月 - 2018年11月
  • 15O-水心筋血流PETにおけるMonte Carlo scaling複合型SSS散乱補正の検討　　　　　　　　　　　　　　　
    孫田 惠一, 志賀 哲, 真鍋 治, 納谷 昌直, 相川 忠夫, 新山 大樹, 平田 健司, 加藤 千恵次, 藤田 勝久, 玉木 長良
    核医学, 2018年11月, (一社)日本核医学会, 日本語
    2018年11月 - 2018年11月
  • FMISO-PETによる心臓サルコイドーシス病変の評価　　　　　　　　　　　　　　　
    古家 翔, 真鍋 治, 大平 洋, 納谷 昌直, 相川 忠夫, 小梁川 和宏, 渡邊 史郎, 小林 健太郎, 平田 健司, 志賀 哲, 真鍋 徳子
    核医学, 2018年11月, (一社)日本核医学会, 日本語
    2018年11月 - 2018年11月
  • Strategy to develop convolutional neural network-based classifier for diagnosis of whole-body FDG PET images　　　　　　　　　　　　　　　
    Keisuke Kawauchi, Kenji Hirata, Seiya Ichikawa, Osamu Manabe, Kentaro Kobayashi, Shiro Watanabe, Miki Haseyama, Takahiro Ogawa, Ren Togo, Tohru Shiga, Chietsugu Katoh
    Society of Nuclear Medicine and Molecular Imaging Annual Meeting (SNMMI), 2018年06月, 英語
    2018年06月 - 2018年06月
  • 心サルコイドーシスにおけるFDG集積定量評価の再現性　　　　　　　　　　　　　　　
    真鍋 治, 平田 健司, 大平 洋, 納谷 昌直, 相川 忠夫, 真鍋 徳子, 志賀 哲
    核医学, 2017年09月, (一社)日本核医学会, 日本語
    2017年09月 - 2017年09月
  • Use of convolutional neural network as the first step of fully automated tumor detection on 11C-methionine brain PET　　　　　　　　　　　　　　　
    Hirata Kenji, Takeuchi Wataru, Yamaguchi Shigeru, Kobayashi Hiroyuki, Terasaka Shunsuke, Toyonaga Takuya, Watanabe Shiro, Kobayashi Kentaro, Manabe Osamu, Kobashi Keiji, Shiga Tohru, Tamaki Nagara
    JOURNAL OF NUCLEAR MEDICINE, 2016年05月01日
    2016年05月01日 - 2016年05月01日
  • Steroid therapy affects the cardiac metabolic shift and requires the careful attention in evaluation of the cardiac sarcoidosis with FDG PET/CT　　　　　　　　　　　　　　　
    Manabe Osamu, Yoshinaga Keiichiro, Ohira Hiroshi, Oyama-Manabe Noriko, Tsujino Ichizo, Hirata Kenji, Kikuchi Hisaya, Nishimura Masaharu, Tamaki Nagara
    JOURNAL OF NUCLEAR MEDICINE, 2016年05月01日
    2016年05月01日 - 2016年05月01日
  • 中咽頭癌に合併し多発骨転移との鑑別が困難であった急性リンパ性白血病の一例　　　　　　　　　　　　　　　
    渡邊 史郎, 真鍋 治, 平田 健司, 菊地 恒矢, 牧野 俊一, 豊永 拓哉, 小林 健太郎, 内山 裕子, 志賀 哲, 加納 里志, 玉木 長良
    核医学, 2016年02月, (一社)日本核医学会, 日本語
    2016年02月 - 2016年02月
  • Primary mucinous cell carcinoma of the skinのリンパ節転移に関するPET-CT所見の検討　　　　　　　　　　　　　　　
    北村 真也, 秦 洋郎, 稲村 有香, 今福 恵輔, 坂下 智博, 平田 健司, 清水 宏
    日本皮膚科学会雑誌, 2015年07月, (公社)日本皮膚科学会, 日本語
    2015年07月 - 2015年07月
  • 小動物用PETを用いた11C‐FlumazenilのBinding potential解析におけるMaximum a posteriori再構成の評価　　　　　　　　　　　　　　　
    孫田惠一, 久保直樹, 趙松吉, 久下裕司, 平田健司, 服部直也, 志賀哲, 加藤千恵次, 玉木長良
    核医学, 2011年, 英語
    2011年 - 2011年
  • もやもや病術後症例に対する追加脳血行再建術—その実際と脳循環代謝
    黒田敏, 中山若樹, 平田健司, 志賀哲, 玉木長良, 宝金清博
    脳循環代謝, 2010年, (一社)日本脳循環代謝学会, 日本語
    2010年 - 2010年
  • 無症候性もやもや病の脳循環代謝—15O‐gas PETによる検討
    長内俊也, 黒田敏, 中山若樹, 平田健司, 平賀哲, 玉木長良, 岩崎喜信
    脳循環代謝, 2008年, 日本語
    2008年 - 2008年
  • 18F‐FDG PETによる頚動脈プラークイメージング
    丸一勝彦, 黒田敏, 中山若樹, 志賀哲, 平田健司, 玉木長良, 岩崎喜信
    脳循環代謝, 2008年, 日本語
    2008年 - 2008年
  • 多発性骨髄腫における全身methionine‐PETの有用性:FDG‐PETとの比較　　　　　　　　　　　　　　　
    鐘ケ江香久子, 岡本祥三, 平田健司, 上林倫史, 趙松吉, 真鍋治, 久下裕司, 玉木長良
    核医学, 2008年, 英語
    2008年 - 2008年
  • 骨転移マーカー1CTPを用いた骨転移評価の役割―骨シンチグラフィ,FDG‐PETとの比較―　　　　　　　　　　　　　　　
    鐘ケ江香久子, 真鍋治, 岡本祥三, 平田健司, 吉永恵一郎, 志賀哲, 趙松吉, 玉木長良
    核医学, 2007年, 英語
    2007年 - 2007年
  • 多発性骨髄腫に対するMET‐PETの有用性の検討‐FDG‐PETとの比較‐　　　　　　　　　　　　　　　
    鐘ケ江香久子, 森田浩一, 岡本祥三, 真鍋治, 平田健司, 吉永恵一郎, 井上哲也, 趙松吉, 玉木長良
    核医学, 2007年, 英語
    2007年 - 2007年

担当経験のある科目_授業

  • データハンドリング演習　　　　　　　　　　　　　　　
    2021年04月 - 現在
  • 機械学習特論　　　　　　　　　　　　　　　
    北海道大学
    2021年04月 - 現在
  • 画像診断研究特論　　　　　　　　　　　　　　　
    北海道大学
    2021年04月 - 現在
  • 医学英語　　　　　　　　　　　　　　　
    2024年04月
  • 統合・臨床腫瘍学　　　　　　　　　　　　　　　
  • 統合・呼吸器　　　　　　　　　　　　　　　
  • 核医学　　　　　　　　　　　　　　　

所属学協会

  • 2022年07月 - 現在
    日本医療情報学会　　　　　　　　　　　　　　　
  • 現在
    日本メディカルAI学会　　　　　　　　　　　　　　　
  • 現在
    日本放射線科専門医会　　　　　　　　　　　　　　　
  • 現在
    日本核医学会　　　　　　　　　　　　　　　
  • 現在
    日本医学放射線学会　　　　　　　　　　　　　　　

Works（作品等）

  • メタボル　　　　　　　　　　　　　　　
    平田健司, 2014年01月22日 - 現在, ［コンピュータソフト］

共同研究・競争的資金等の研究課題

  • がんセノリティクス治療の局所制御と非侵襲的イメージングによる高精度化に向けた研究
    科学研究費助成事業
    2023年06月30日 - 2026年03月31日
    安井 博宣, 稲波 修, 平田 健司, 久下 裕司
    日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 23K18259
  • 慢性肺血栓塞栓性肺高血圧症の呼吸困難に関する検討
    科学研究費助成事業
    2023年04月01日 - 2026年03月31日
    佐藤 隆博, 辻野 一三, 平田 健司, 清水 薫子
    慢性肺血栓塞栓性肺高血圧症(Chronic thromboembolic pulmonary hypertension (CTEPH))における治療後残存息切れの原因を明らかにし、息切れと関連する指標、適切な対処方法を確立することを目的に研究をしている。下記(A)～(C)の指標との関連を検討することを目的としている。
    (A)心臓の形態・機能異常の評価系の確立。これは、従来、PH症例の心臓形態・機能の評価は血中脳性ナトリウム利尿ペプチド濃度、心エコー、心臓カテーテル検査などで行われてきた。これらの指標は治療の適正化や予後予測の上で有用である。しかし、従来の指標は負荷依存性であり心臓固有の機能を反映しないという問題があった。その中で近年、心臓MRIと右心カテーテル指標を組み合わせることで右室固有の収縮・拡張能を算出している。
    (B)呼吸機能と肺容積の評価系の確立。CTEPH症例では、拘束性障害や閉塞性障害を認めることが報告されているが、治療前後の変化については報告がない。本研究では治療前後の呼吸機能を呼吸機能検査（含肺拡散能力）と肺CTを用いて比較する。CTでは肺容積をAVIEWTMを用いて算出し解析する。これらと治療前後の息切れの程度・質、運動耐用能（6分間歩行距離およびボルグ指数、最大酸素摂取量）との関連を解析する。
    (C)肺循環動態の安静時、運動負荷時の定量的評価を確立。15OでラベリングしたH20(水)をトレーサーとして用いたPET検査にて肺内血流量測定を行い息切れとの関連を検討する。
    現在、CTEPH症例のカテーテル治療後の症例が10例ほど蓄積されてきており、次年度はこれらの結果を学会発表、論文発表していく予定とされている。
    日本学術振興会, 基盤研究(C), 北海道大学, 23K07593
  • 患者フレンドリーな核医学検査のための情報技術利用の検証と開発
    科学研究費助成事業
    2023年04月01日 - 2026年03月31日
    工藤 崇, 井手口 怜子, 西 弘大, 平田 健司
    日本学術振興会, 基盤研究(C), 長崎大学, 23K07067
  • がんの放射線や免疫療法に伴う心血管障害の画像評価に関する研究
    科学研究費助成事業
    2023年04月01日 - 2026年03月31日
    玉木 長良, 酒井 晃二, 平田 健司, 真鍋 治, 鈴木 弦, 全 完
    日本学術振興会, 基盤研究(C), 京都医療科学大学, 23K07089
  • エネルギー代謝に着目した核医学イメージングによるがん微小環境評価
    科学研究費助成事業
    2022年04月01日 - 2026年03月31日
    小川 美香子, 平田 健司, 久下 裕司, 鍛代 悠一
    日本学術振興会, 基盤研究(B), 北海道大学, 22H03009
  • 顎骨定量SPECTの施設間標準化(ハーモナイゼーション)を目指して
    科学研究費助成事業
    2022年04月01日 - 2025年03月31日
    秦 浩信, 北川 善政, 平田 健司, 三輪 建太, 今待 賢治, 佐藤 淳, 松坂 方士, 浅香 卓哉
    日本学術振興会, 基盤研究(C), 独立行政法人国立病院機構北海道がんセンター(臨床研究部), 22K10137
  • 膠芽腫における低酸素内糖代謝亢進メカニズムの検証
    科学研究費助成事業
    2022年04月01日 - 2025年03月31日
    山口 秀, 平田 健司, 茂木 洋晃
    日本学術振興会, 基盤研究(C), 北海道大学, 22K09225
  • 深層学習を活用した多面的病理学的検討による、小児期発症肺高血圧症の病態解明
    科学研究費助成事業
    2022年04月01日 - 2025年03月31日
    永井 礼子, 武田 充人, 正木 直樹, 高桑 恵美, 杉森 博行, 平田 健司, 齋木 佳克
    日本学術振興会, 基盤研究(C), 北海道大学, 22K08225
  • 低酸素評価に基づく新しい口腔癌治療戦略の構築
    科学研究費助成事業
    2022年04月01日 - 2025年03月31日
    北川 善政, 竹内 康人, 渡邊 史郎, 平田 健司, 大賀 則孝, 佐藤 淳, 犬伏 正幸
    日本学術振興会, 基盤研究(B), 北海道大学, 22H03285
  • フェロトーシス誘導がん治療のPETイメージング
    科学研究費助成事業 基盤研究(B)
    2021年04月01日 - 2025年03月31日
    久下 裕司, 安井 博宣, 小川 美香子, 平田 健司, 水野 雄貴
    近年、フェロトーシスと呼ばれる新しい細胞死様式が報告され、フェロトーシスを誘導する薬剤が新たながん治療薬として注目されている。このフェロトーシスの進行には、トランスフェリン受容体1 (TfR1) が深く関与することが知られている。本研究の目的は、TfR1の特異的イメージングを可能とする新たなPETイメージング剤を合成し、PETによるTfR1イメージングがフェロトーシス誘導剤の治療効果予測/判定やフェロトーシス誘導剤の開発に有効な手段となるか否かを明らかにすることにある。
    本目的達成のため、これまでに主に新たなPETイメージング剤の合成検討、及びIn vitro細胞実験を行った。その結果、TfR1への親和性を有する7残基直鎖ペプチド (DT7) を母体とした68Ga標識プローブ（68Ga-DT7）が、T98G (TfR1高発現細胞株) に対してTfR1特異的に集積することを見出した。一方で、その集積量はやや低かったことから、分子内に2つのDT7ペプチドを有する2価DT7を新たに設計し、合成に成功した。しかし、68Gaで標識した2価DT7のT98Gへの集積量は予想に反して低かった。さらに、直鎖上のDT7ペプチドを環状化した環化ペプチドを合成し、T98Gへの集積量を評価したが、TfR1特異的集積量の向上には繋がらなかった。
    上記検討結果から、TfR1への親和性がより高いリガンドを母体としたプローブを開発する必要性が示唆された。そこで、cystine dense peptideの１種でありTfR1との高い結合親和性を有するTfRB1G3を母体としたプローブの開発を開始した。
    日本学術振興会, 基盤研究(B), 北海道大学, 21H02858
  • 難治性顎骨骨髄炎の低酸素分子イメージングによる新規診断ストラテジー
    科学研究費助成事業
    2022年06月30日 - 2024年03月31日
    北川 善政, 平田 健司, 渡邊 史郎, 佐藤 淳, 浅香 卓哉, 竹内 康人, 犬伏 正幸, 網塚 憲生
    日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 22K19608
  • 乳癌の再発転移予測に向けたMRIと半導体PETのバイオマーカーによる微小環境評価
    科学研究費助成事業 基盤研究(C)
    2021年04月01日 - 2024年03月31日
    加藤 扶美, 松野 吉宏, 平田 健司, 竹下 卓志
    乳癌はホルモン受容体やHER2の発現や細胞増殖能といったバイオマーカーにより複数のサブタイプに分類され、使用すべき薬剤などの治療戦略や予後が異なる。
    造影ダイナミック撮像や拡散強調像などを含めたMRIからは腫瘍の形態や血流および機能、FDG PET-CTからは糖代謝といった画像バイオマーカーが非侵襲的に取得できる。MRIの機能画像の代表である拡散強調像のみかけの拡散係数（ADC値）や拡散尖度画像のK値は悪性度の指標の一つとされている。
    我々の施設では、MRIやFDG PET-CTから得られる血流、機能、代謝などの画像バイオマーカーを用いて乳癌の治療抵抗性や転移・再発、予後などを予測するモデルを確立するため、乳癌患者のMRIやFDG PET-CTの画像データをテキスチャ解析という不均一さなどの人の目では捉えられないような画像の特徴を評価する方法を用いて解析し、乳癌の薬物療法の治療効果、乳癌の再発・転移の有無および予後などの臨床的データと比較し、治療抵抗性や転移・再発リスクに関連するMRIやFDG PET-CT画像の特徴を見いだすために、臨床データの収集および画像解析を進め、検討中である。
    これまでにMRIを撮像した乳癌患者の症例リストを作成し、術前療法の有無とその効果、転移・再発の有無といった臨床データを収集中である。また、MRI画像データを収集しテキスチャ解析などの画像解析を行う準備を進めている。MRIの撮像体位とあわせて腹臥位でFDG PET-CTを撮像するためのプロトコール作成を行った。
    日本学術振興会, 基盤研究(C), 北海道大学, 21K07664
  • 光免疫療法のためのナビゲーションシステムの開発
    科学研究費助成事業 基盤研究(C)
    2021年04月01日 - 2024年03月31日
    曽山 武士, 工藤 與亮, 平田 健司
    2021年度は、当初予定していたフュージョンビューワーの改良やデジタルファントムを用いた照射予想域の表示に留まらず、光量分布集計機能を持つ「高精度光免疫治療システム」の開発に着手した。また、このシステムの基礎的検討を行うために、①臨床解剖に即した構造を有し、②穿刺可能、③開口可能、④CTによる腫瘍・穿刺位置の客観的評価が可能な頭頸部ファントムを開発し、7月3日の第6回 日本穿刺ドレナージ研究会と11月26日の第36回 道東画像診断・治療ケア研究会で報告した。
    光免疫療法のためのナビゲーションシステムを臨床で使用する際に、コーンビームCT撮像時にアーチファクトを発生しうる金属製のデバイスが問題であった。そこで、2021年度にCAD でデザインし3Dプリンターで印刷した非金属製開口器と非金属製ガイドニードルを開発し、11月26日の第36回 かしわ画像研究会で報告した。
    また、歯肉癌を想定した光免疫療法のためのナビゲーションデバイスとして、2021年度にインプラントの際にドリルで下顎骨に穴を空ける技術を応用し、光ファイバーの穿刺を計画通りに行うことのできる穿刺ガイドプレートを開発し、11月26日の第36回 かしわ画像研究会で報告した。
    この他、2021年度は柔軟な舌を有する頭頸部模型を開発し、これを用いて光免疫療法の術前画像と術中画像の非剛体画像レジストレーションの精度評価に取り組んだが、非剛体画像レジストレーションを行うとほとんど重ね合わせの誤差が発生せず、一方で原版の光免疫療法のためのナビゲーションシステムは重ね合わせが出来ないことが判明したため、これらの比較実験は行なっていない。
    日本学術振興会, 基盤研究(C), 北海道大学, 21K07717
  • 最新のデジタル半導体PET装置に対応した心臓動態ファントムの開発と撮像技術の確立
    科学研究費助成事業 基盤研究(C)
    2021年04月01日 - 2024年03月31日
    孫田 惠一, 山品 博子, 納谷 昌直, 平田 健司
    本研究では、デジタル半導体PETに対応する心臓サルコイドーシスおよび冠動脈プラークによる炎症病変を含むヒト心臓を再現したファントムを開発することである。
    令和3年度はファントムの完成形を想定した上で数多くの予備実験を遂行した。年度初めに、研究分担者および研究協力者の方々とともにプロジェクト内容の確認を行い、そして製作工程に関する検討を行った。当該年度は、製作するファントムにおいて最も重要な核となる冠動脈部分をいかに再現するかに注力することとなった。冠動脈は直径2-4ミリと細い上に、心拍による心臓そのものによる動きに耐えうるような素材である必要がある。さらに、成形には心臓モデルデータより3Dプリンタを利用して行うため、取り回しが容易であることも素材選定には重要な要素であることがわかった。本報告で具体的な素材名は列挙しないが、様々な素材を用いて多くの予備実験を重ねることで最適な素材を見出すことができた。続いて、冠動脈が貼り付く部分となる心筋および心内腔部分の製作に関して検討を行った。心拍による動きはこの部分に何らかの工夫をすることで再現することとなるが、風船のように内部へ水圧を加えることで動きを再現する方法を採用することとした。従って、心筋部分はこの水圧に耐えうる素材であることが重要であるため、冠動脈部分と同様にいくつかの素材で予備実験を行うことで最適なものを見出すことができた。水圧のコントロールに関しては、様々な心拍数およびリズムを再現できることが重要である。研究計画時には水ポンプとそれをコントロールするためのプログラマブルなPCを組み合わせることで実現することを想定していたが、開発には時間を要することが判明したため研究の遅れが懸念されたため、同性能既製品を用いることを考えている。現在はその機種選定を行っているところである。
    日本学術振興会, 基盤研究(C), 北海道大学, 21K12698
  • 左室駆出率が保持された心不全に対する個別化医療を目指した多分野融合研究
    科学研究費助成事業 基盤研究(B)
    2020年04月01日 - 2024年03月31日
    安斉 俊久, 永井 利幸, 小川 貴弘, 横田 勲, 清水 厚志, 平田 健司, 小柴 生造, 櫻井 美佳
    HFpEF計500症例を目標に以下の組み入れ基準・除外基準で北海道大学病院を含む全国24施設からElectronic Data Captureシステムを用いて詳細な臨床情報を含めて登録し、各種解析を並行して実施した。組み入れ基準：外来もしくは入院心不全症例：①20歳以上でフラミンガム心不全診断基準を満足する心不全症状/所見があり、②左室駆出率50％以上かつBNP値100pg/mLを超えるもしくはN末端proBNP値400 pg/mLを超える、③本人からの文書同意が可能。除外基準：①敗血症、②心筋炎、③閉塞型肥大型心筋症、④拘束型心筋症、⑤重度の弁膜症、⑥心臓移植後あるいは待機、⑦1か月以内の予定心臓手術各種解析：①心不全マルチバイオマーカー解析 ②アレイ（ゲノムワイド関連）解析 ③網羅的メタボローム解析 ④人工知能解析
    今年度は昨年度に引き続き、上記基準に該当する心不全症例の登録を開始してきた。令和4年3月末の時点で、目標症例数を超えるHFpEF664例の登録が得られ、バイオマーカー、アレイ、メタボローム解析も完了した。また、歩行動画の統一条件撮影に関しては昨年度特許申請に至った撮影アプリケーションを用いて現在歩行動画が回収できた192例に対し、歩行パターンの機械学習によるクラスター解析を行っており、教師なし学習で臨床医が判定した臨床フレイルスケールを高い弁別能で予測出来ることに加え、予後との関連も明らかになりつつある。
    日本学術振興会, 基盤研究(B), 北海道大学, 20H03670
  • 半導体PETと深層学習を利用したFDG PETからの腫瘍血流・代謝の同時定量
    科学研究費助成事業 基盤研究(C)
    2020年04月01日 - 2023年03月31日
    平田 健司, 竹内 啓, 真鍋 治, 久下 裕司
    F-18 fluorodeoxyglucose (FDG)はブドウ糖類似体であり、体内に投与してからポジトロン断層法(PET)で撮影することにより、体内の糖代謝の多寡を画像化できる。原理的には、FDGを投与した直後から連続PET撮影した画像は血流の情報を含む。血流成分を抽出する試みは過去にも行われてきたが、PETの空間分解能の低さによるarterial input function (AIF)取得の困難さ等のため、臨床的に使用されるレベルには至っていない。腫瘍の血流にはdrug deliveryや治療効果判定に関する重要な情報が含まれていると考えられる。そこで本研究では新技術を導入することで、FDGによる腫瘍の糖代謝・血流の同時定量を目指した。今回申請者らが用いる新技術は、ハードウェアとしては高い空間分解能を持つ半導体PETであり、ソフトウェアとしては機械学習の一種であるdeep neural network (DNN)である。高い空間分解能は小さい血管からのAIF取得に役立ち、DNNはコンパートメントモデル・フリーで直接血流を予測するregressorとなりうる。腫瘍血流はO-15標識水のPETによる測定値をgold standardとする。1回のFDG PET撮影で患者負担の増加なしに糖代謝と同時に腫瘍血流が定量することを目指している。2年目である2021年度も新規の前向き臨床試験の立ち上げには到達できなかったが、PETのAI解析に向けて不足するエビデンスを固めるため、O-15標識水やFDGによる後ろ向き研究やファントム実験、画像診断レポートと画像とを組み合わせる研究等を行った。とくにO-15標識水に関しては、PET撮影した肺画像をUCLAの研究者とともに解析し、肺血流の定量値を得ることに成功し、腫瘍血流定量につながる成果が得られた。
    日本学術振興会, 基盤研究(C), 北海道大学, 20K08015
  • 心サルコイドーシスの個別化診療に向けたMRIとPET統合テクスチャ解析法の開発
    科学研究費助成事業 基盤研究(C)
    2020年04月01日 - 2023年03月31日
    真鍋 徳子, 大平 洋, 平田 健司, 真鍋 治
    2020年から2021年度にかけて、心臓サルコイドーシスの診断基準の主徴候である心臓MRIとPETそれぞれを独立して定性および定量評価した。
    PETにおいては、定性評価の診断能向上のために、従来の撮影に加えて後期相を追加することで生理的集積を抑制し、心臓サルコイドーシス病変の検出能と特異度向上が期待されることを報告した（後述論文リスト）。心臓MRIにおいては、従来の評価法である遅延造影の左室全体および左室のセグメント毎の定性および定量評価に加えて、既存のシネMRIデータを用いたfeature tracking法によるセグメント毎の局所的な壁運動の定量化（ストレイン解析）を追加した。遅延造影を用いたテクスチャ解析評価については、すでに先行研究で行った遅延造影CTデータを用いて方法論を確立し報告した（後述論文リスト）。
    また、上記画像によるイメージングバイオマーカーに加えて、サルコイドーシス/肉芽腫性疾患学会の診断基準、及びサルコイドーシスの重症度分類結果も追記する心臓関連イベントを含む臨床経過を加えたデータベースを作成した。これらの経過はファーストオーサー1編、コレスポンディングオーサー4編として査読のある国際英文誌に掲載済みである。
    また下記学会等での講演においても研究成果を報告している。
    虚血および非虚血性心筋症に対する心臓MRIの現在（第61回日本核医学会学術総会 IAEA心臓核医学ワークショップ2021年11月3日WEB）、心臓機能画像のアップデート（第61回日本核医学学術総会 2021年11月5日名古屋）、心臓核医学の最新の話題（Womens Cardiologist Conference 2022年2月10日 WEB）、MRIのマッピング技術による循環器画像診断の新たな潮流．（第1回関東心臓MRI研究会2022年2月26日東京）。
    日本学術振興会, 基盤研究(C), 自治医科大学, 20K08042
  • 人工知能技術を利用した医用画像診断支援システムの倫理リスクマネジメント手法の研究
    科学研究費助成事業 基盤研究(C)
    2020年04月01日 - 2023年03月31日
    平田 雄一, 平田 健司, 南須原 康行, 白土 博樹
    本研究は、将来的に重要性が増すと予想される人工知能技術を利用した医用画像診断支援システムの倫理リスクを具体化するための新しいリスクマネジメント手法の構築を試み、人工知能技術を利用した医用画像診断支援システムの倫理リスクの低減策の検討を詳細に深く行えるようにすることを目的とした。
    具体的には、本研究では、医学物理学の放射線治療分野や放射線安全管理分野において、既に活用されている複雑なシステムを、システムの要素(コンポーネント)間の入力と出力により決定される制御関係の安全性に着目して解析する安全解析手法であるSTAMP(System Theoretic Accident Model and Processes)を、人工知能技術を利用した医用画像診断支援システムの倫理リスクのリスクマネジメントに応用した。
    2020年度は、新しい倫理リスク・マネジメント・モデルを、医用画像に関する倫理リスク事項のネットワークを高速に処理するために本研究で購入した高速データ処理が可能な高性能ワークステーション上に実装されたSTAMPのモデリングツールであるSTAMP Workbenchを基盤とした新しい倫理リスク・モデリング・システムにより構築した。
    その結果、本研究で構築した、STAMP Workbenchを基盤とした、人工知能技術を利用した医用画像診断支援システムの新しい倫理リスクマネジメント手法は、放射線治療における事故防止のための強力なツールとなりえることが明らかになった。
    そして、日本放射線腫瘍学会第33回学術大会において、本研究の分担者全員と共同して上記研究結果を発表した。
    日本学術振興会, 基盤研究(C), 北海道大学, 20K12708
  • 高分解能PET装置を用いた冠動脈プラーク炎症病変の可視化と心筋梗塞発症の機序解明
    科学研究費助成事業 基盤研究(B)
    2019年04月01日 - 2022年03月31日
    納谷 昌直, 孫田 惠一, 平田 健司, 真鍋 治, 真鍋 徳子, 志賀 哲, 石田 雄介, 長内 俊也
    北海道大学病院での自主臨床試験への承認を得て、健常人６名、安定狭心症患者９名、急性心筋梗塞患者34名の計49名を前向きに登録した。18F-FDG digital PET/CTを施行し、SUV値から炎症活動度を測定した。撮像プロトコルの最適化を行い、冠動脈左主幹部、左前下行枝、左回旋枝、右冠動脈の動脈炎症を可視化した。頸動脈、胸部大動脈、腹部大動脈に集積したFDGの集積強度、集積範囲をSUVmax値を用いて、客観的かつ定量的に測定できた。左前下行枝近位部のSUVmax値を健常者、安定狭心症患者、急性心筋梗塞患者の3群で比較したところ急性心筋梗塞患者で高値であった。
    日本学術振興会, 基盤研究(B), 北海道大学, 19H03592
  • 新規放射性薬剤IIMUによる頭頸部癌化学療法の治療前効果予測法の確立
    科学研究費助成事業 若手研究(B)
    2016年04月01日 - 2018年03月31日
    平田 健司
    本研究の目的はチミジンホスホリラーゼのSPECT製剤である123I-IIMUを頭頸部癌患者に投与して臨床的有用性を示すことであったが、研究期間内はIIMUを患者に投与することができなかった。IIMUの原料である123I-NaI溶液（メーカーからの購入品）の組成が変更され、合成収率が低下したためである。そこで本研究期間には変更後の溶液組成に合わせたIIMU標識合成条件及び精製条件の再検討を行い、収率50%以上でIIMUを製造できることを確認し、マウスに投与して問題なく使用できることを確認できた。並行してFDG PETの臨床画像を後向きに検討し、体積および不均一性の指標の臨床有用性を明らかにした。
    日本学術振興会, 若手研究(B), 北海道大学, 16K19798
  • 低酸素イメージングを中心とした複合的な脳腫瘍診断法・治療法の確立
    科学研究費助成事業 若手研究(B)
    2012年 - 2012年
    平田 健司
    原発性脳腫瘍の臨床において、手術を行わずに非侵襲的な方法で腫瘍の性質を明らかにする画像診断の果たす役割は大きい。本研究では、MRI等の既存の診断法に加えて、低酸素イメージング製剤F-18 fluoromisonidazole(FMISO)を用いたポジトロン断層撮影法(PET)を用いることで、神経膠腫の非侵襲的な鑑別診断法の確立を目指すことを目的とした。神経膠腫23症例に対して、FMISOPETを行い、その画像所見を術後病理所見と比較した。23例中14例が病理学的にWHO grade IVの神経膠芽腫であったが、これらはすべてFMISO集積亢進を示した。また残りの9例はgrade IIまたはIIIの神経膠腫であったが、これらはすべてFMISO集積陰性であった。この結果からFMISO PETによってgrade IVか、grade III以下かを鑑別することができると考えられた。さらに、神経膠芽腫のうち10例に、高分解能半導体PETでのFMISO PETおよび糖代謝を反映するFDG PETを行った。半導体PETの高い空間分解能を利用して腫瘍内の局所的な集積強弱を評価することによって、腫瘍内の分布のFMISOとFDGの分布がよく一致する症例(N=4)と、乖離する症例(N=6)が存在することを見出した。前者は嫌気性糖代謝が中心で、後者は好気性糖代謝が中心と考えられ、神経膠芽腫の中にも好気性のものと嫌気性のものが存在することがわかった。両者の治療反応性や予後の差異について今後研究を進める予定である。また、本研究に関連して、脳腫瘍の診断に用いられるメチオニンPETが、非腫瘍性の脳炎の診断にも有用であることを見出したので、これを報告した。
    日本学術振興会, 若手研究(B), 北海道大学, 24700999
  • 心筋血管再生治療のための新しい生体内遺伝子発現イメージング法の確立と応用
    科学研究費助成事業 基盤研究(B)
    2006年 - 2008年
    犬伏 正幸, 玉木 長良, 森田 浩一, 志賀 哲, 鐘ヶ江 香久子, 井上 哲也, 岡本 祥三, 平田 健司, 吉永 恵一郎, 畠山 昌則
    近年、虚血性心疾患に対して、血管新生因子を発現する遺伝子を投与することによって血管を再生させる血管新生遺伝子治療の研究が活発に行われている。しかしこれまでは治療遺伝子の発現部位や量を生体内で確認することができず、治療効果を正確に評価することが困難であった。本研究では、治療遺伝子の発現を生体内で画像として捉える方法を確立し、さらに幹細胞/前駆細胞の細胞移植治療における移植細胞の追跡への応用を試みた。
    日本学術振興会, 基盤研究(B), 18390326