研究者情報

マスター

アカウント（マスター）

• 氏名

  西岡　健太郎(ニシオカ　ケンタロウ), ニシオカ　ケンタロウ

所属（マスター）

• 医学研究院　医理工学グローバルセンター

所属（マスター）

• 医学研究院　医理工学グローバルセンター

独自項目

syllabus

• 2021, Medical Physics School, Medical Physics School, 修士課程, 医理工学院, radiation treatment, particle therapy, medical physics, radiobiology, radiomics
• 2021, 医療機器臨床研究特論, Advanced Cource of Medical Device Clinical Research, 修士課程, 医理工学院, 放射線治療、粒子線治療、癌治療、医学物理学、医療機器、臨床研究 Radiation oncology, particle therapy, cancer treatment, medical physics, medical equipment, clinical study
• 2021, 総合医理工学研究Ⅰ, General Research on Biomedical Science and Engineering I, 修士課程, 医理工学院, 放射線治療、粒子線治療、放射線腫瘍学、医学物理学
• 2021, 総合医理工学研究Ⅱ, General Research on Biomedical Science and Engineering II, 修士課程, 医理工学院, 放射線治療、粒子線治療、放射線腫瘍学、医学物理学
• 2021, 医理工連携放射線腫瘍学, Radiation Oncology for Cooperation with Biomedical Science and Engineering, 修士課程, 医理工学院, 臨床医学、解剖学、生理学、腫瘍癌、放射線治療、粒子線治療、癌治療 Clinical medicine, anatomy, physiology, oncology, radiation oncology, particle therapy, cancer treatment
• 2021, 先端医理工学研究Ⅰ, Advanced Research on Biomedical Science and Engineering I, 博士後期課程, 医理工学院, 放射線治療、粒子線治療、放射線腫瘍学、医学物理学
• 2021, 先端医理工学研究Ⅱ, Advanced Research on Biomedical Science and Engineering II, 博士後期課程, 医理工学院, 放射線治療、粒子線治療、放射線腫瘍学、医学物理学

researchmap

プロフィール情報

学位

• 博士(医学)（北海道大学）

プロフィール情報

• 姓

  西岡

• 名

  健太郎

• ID各種

  201501030882736522

業績リスト

研究キーワード

• モデルベースドアプローチ   正常組織障害発生確率(NTCP)モデル   陽子線治療   泌尿器腫瘍   脳脊髄腫瘍   

研究分野

• ライフサイエンス / 放射線科学 / 放射線治療学

経歴

• 2020年04月 - 現在 北海道大学 医学研究院 医理工学グローバルセンター 助教
• 2014年10月 - 2020年03月 北海道大学 医学研究科 放射線治療医学分野 特任助教
• 2010年04月 - 2014年09月 北海道大学病院 放射線治療科 医員
• 2008年04月 - 2010年03月 北海道がんセンター 放射線治療科 医師
• 2007年04月 - 2008年03月 北海道大学病院 放射線科 医員
• 2005年04月 - 2007年03月 北海道大学病院 卒後臨床研修センター 初期臨床研修医

学歴

• 2010年04月 - 2014年03月   北海道大学大学院   医学研究院
• 1999年04月 - 2005年03月   北海道大学   医学部   医学科

受賞

• 2023年12月 日本放射線腫瘍学会 優秀教育講演賞
   教育講演-膀胱癌
• 2011年05月 日本医学放射線学会 CyPos賞 Silver medal
  

論文

• Decision regret after curative treatment and its association with the decision-making process and quality of life for prostate cancer patients.

  Miho Sato, Takahiro Osawa, Kentaro Nishioka, Tomohiko Miyazaki, Shuhei Takahashi, Takashi Mori, Takayuki Hashimoto, Haruka Miyata, Ryuji Matsumoto, Takashige Abe, Kazuki Ohashi, Sachiyo Murai, Yoichi M Ito, Nobuo Shinohara

  International journal of urology : official journal of the Japanese Urological Association 2024年10月09日 

  OBJECTIVES: To determine how the treatment decision-making process and posttreatment health-related quality of life (HRQOL) are related to regret about treatment choice for prostate cancer patients in Japan. METHODS: We invited a total of 614 patients who were treated with radiation therapy (RT), radical prostatectomy (RP), or active surveillance/watchful waiting (AS/WW) from April 2007 to March 2021. Posttreatment regret was evaluated by the Decision Regret Scale. HRQOL was evaluated by the Expanded Prostate Cancer Index Composite and the 12-item Short Form Survey. The decision-making process was assessed by patient evaluation of the decision-making process. We compared the decision regret scale scores across treatment types, HRQOL, and decision-making processes. RESULTS: Data from 371 patients were analyzed (RT: 202, RP: 149, AS/WW: 20). The median length of time since treatment was 64 (IQR: 43-93) months. The decision regret scale scores were not significantly different among the treatment groups but were significantly greater (strong regret) in patients with poor urinary summary scores, bowel summary scores, and hormonal summary scores. The decision regret scale scores were significantly lower (less regret) for patients who reported being adequately informed at the time of the treatment decision and who had adequately communicated their questions and concerns to physicians than for patients who reported less adequate communication. This result was also observed among patients who reported low HRQOL scores. CONCLUSIONS: These findings underline the important influence of posttreatment HRQOL and decision-making as an interactive process between physicians and their patients on posttreatment regret in prostate cancer patients.
• A simulation study of MR-guided proton therapy system using iron-yoked superconducting open MRI: a conceptual study.

  Yusuke Fujii, Hideaki Ueda, Taisuke Takayanagi, Kentaro Nishioka, Takashi Mori, Takayuki Hashimoto, Hidefumi Aoyama, Kikuo Umegaki, Taeko Matsuura

  Journal of radiation research 2024年10月04日 

  Radiotherapy platforms integrated with magnetic resonance imaging (MRI) have been significantly successful and widely used in X-ray therapy over the previous decade. MRI provides greater soft-tissue contrast than conventional X-ray techniques, which enables more precise radiotherapy with on-couch adaptive treatment planning and direct tracking of moving tumors. The integration of MRI into a proton beam irradiation system (PBS) is still in the research stage. However, this could be beneficial as proton therapy is more sensitive to anatomical changes and organ motion. In this simulation study, we considered the integration of PBS into the 0.3-T superconducting open MRI system. Our proposed design involves proton beams traversing a hole at the center of the iron yoke, which allows for a reduced fringe field in the irradiation nozzle while maintaining a large proton scan field of the current PBS. The shape of the bipolar MRI magnets was derived to achieve a large MRI field-of-view. To monitor the beam position and size accurately while maintaining a small beam size, the beam monitor installation was redesigned from the current system. The feasibility of this system was then demonstrated by the treatment plan quality, which showed that the magnetic field did not deteriorate the plan quality from that without the magnetic field for both a rectangular target and a prostate case. Although numerous challenges remain before the proposed simulation model can be implemented in a clinical setting, the presented conceptual design could assist in the initial design for the realization of the MR-guided proton therapy.
• Patterns of Care for Brain Metastases in Asia: A Real-World Survey Conducted by the Federation of Asian Organizations for Radiation Oncology.

  Yusuke Uchinami, Archya Dasgupta, Kentaro Nishioka, Handoko, Jayant Sastri Goda, Jun Won Kim, Rizma Mohd Zaid, Ooi Kai Yun, Humera Mehmood, Imjai Chitapanarux, Supriya Chopra, Hidefumi Aoyama

  JCO global oncology 10 e2400222  2024年10月 [査読有り]
   

  PURPOSE: To report the patterns of care for brain metastases (BMs) in the Federation of Asian Organizations for Radiation Oncology (FARO). METHODS: Overall, 37 questions were prepared. The survey was conducted online using Google Forms, and the URL was distributed to members of the FARO research committee. Radiation oncologists associated with FARO responded to the questionnaire between May 2023 and June 2023, and their answers were analyzed. RESULTS: Responses were received from 32 radiation oncologists in 13 countries participating in FARO. Twenty-six physicians (81.3%) were affiliated with academic centers, and 22 (68.8%) were able to perform stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (fSRT) for BMs at their institution. The most typically used prognostic index for BM was the recursive partitioning analysis classification (17 physicians, 53.1%). The maximum number of BMs indicated for SRT/SRS was ≤three (11 physicians, 34.4%), whereas eight (25.0%) physicians answered for 6-10 BMs. The maximum size of BMs considered for SRS/fSRT was ≤3 cm (14 physicians, 43.8%), whereas nine (28.1%) answered that SRS/fSRT was preferred if the maximum size was >4 cm. When whole-brain radiotherapy (RT) was indicated, hippocampal avoidance and memantine usage were limited to 50.0% and 25.0% of patients, respectively. The most typical RT modality after BM resection was SRS/fSRT alone, regardless of whether the margin was positive (19 physicians, 59.4%) or negative (13 physicians, 40.6%). CONCLUSION: We report the survey results of the patterns of care for BMs in the FARO. This survey was conducted only among a limited number of FARO members. Since many respondents were affiliated with relatively large-scale academic centers, large-scale surveys, including community hospitals, are warranted for future initiatives.
• Geometric target margin strategy of proton craniospinal irradiation for pediatric medulloblastoma.

  Takaaki Yoshimura, Keigo Kondo, Takayuki Hashimoto, Kentaro Nishioka, Takashi Mori, Takahiro Kanehira, Taeko Matsuura, Seishin Takao, Hiroshi Tamura, Takuya Matsumoto, Kenneth Sutherland, Hidefumi Aoyama

  Journal of radiation research 2024年09月15日 

  In proton craniospinal irradiation (CSI) for skeletally immature pediatric patients, a treatment plan should be developed to ensure that the dose is uniformly delivered to all vertebrae, considering the effects on bone growth balance. The technical (t) clinical target volume (CTV) is conventionally set by manually expanding the CTV from the entire intracranial space and thecal sac, based on the physician's experience. However, there are differences in contouring methods among physicians. Therefore, we aimed to propose a new geometric target margin strategy. Nine pediatric patients with medulloblastoma who underwent proton CSI were enrolled. We measured the following water equivalent lengths for each vertebra in each patient: body surface to the dorsal spinal canal, vertebral limbus, ventral spinal canal and spinous processes. A simulated tCTV (stCTV) was created by assigning geometric margins to the spinal canal using the measurement results such that the vertebral limb and dose distribution coincided with a margin assigned to account for the uncertainty of the proton beam range. The stCTV with a growth factor (correlation between body surface area and age) and tCTV were compared and evaluated. The median values of each index for cervical, thoracic and lumber spine were: the Hausdorff distance, 9.14, 9.84 and 9.77 mm; mean distance-to-agreement, 3.26, 2.65 and 2.64 mm; Dice coefficient, 0.84, 0.81 and 0.82 and Jaccard coefficient, 0.50, 0.60 and 0.62, respectively. The geometric target margin setting method used in this study was useful for creating an stCTV to ensure consistent and uniform planning.
• Clinical outcome, radiological findings, and genetic features of IDH-mutant brainstem glioma in adults.

  Sogo Oki, Yukitomo Ishi, Ryosuke Sawaya, Michinari Okamoto, Hiroaki Motegi, Zen-Ichi Tanei, Masumi Tsuda, Takashi Mori, Kentaro Nishioka, Hiromi Kanno-Okada, Hidefumi Aoyama, Shinya Tanaka, Shigeru Yamaguchi, Miki Fujimura

  Acta neurochirurgica 166 1 263 - 263 2024年06月12日 

  BACKGROUND: With the recent advent of genetic testing, IDH-mutant glioma has been found among adult brainstem gliomas. However, the clinical outcome and prognosis of IDH-mutant brainstem gliomas in adults have not been elucidated. This study aimed to investigate the clinical outcome, radiological findings, and genetic features of adult patients with IDH-mutant diffuse brainstem gliomas. METHODS: Data from adult patients with brainstem glioma at Hokkaido University Hospital between 2006 and 2022 were retrospectively analyzed. Patient characteristics, treatment methods, genetic features, and prognosis were evaluated. RESULTS: Of 12 patients with brainstem glioma with proven histopathology, 4 were identified with IDH mutation. All patients underwent local radiotherapy with 54 Gray in 27 fractions combined with chemotherapy with temozolomide. Three patients had IDH1 R132H mutation and one had IDH2 R172G mutation. The median progression-free survival and overall survival were 68.4 months and 85.2 months, respectively, longer than that for IDH-wildtype gliomas (5.6 months and 12.0 months, respectively). At the time of initial onset, contrast-enhanced lesions were observed in two of the four cases in magnetic resonance imaging. CONCLUSION: As some adult brainstem gliomas have IDH mutations, and a clearly different prognosis from those with IDH-wildtype, biopsies are proactively considered to confirm the genotype.
• A Single-Institution Prospective Study To Evaluate the Safety and Efficacy of Real- Time Image-Gated Spot-Scanning Proton Therapy (RGPT) for Prostate Cancer.

  Kentaro Nishioka, Takayuki Hashimoto, Takashi Mori, Yusuke Uchinami, Rumiko Kinoshita, Norio Katoh, Hiroshi Taguchi, Koichi Yasuda, Yoichi M Ito, Seishin Takao, Masaya Tamura, Taeko Matsuura, Shinichi Shimizu, Hiroki Shirato, Hidefumi Aoyama

  Advances in radiation oncology 9 5 101464 - 101464 2024年05月 

  PURPOSE: In real-time image-gated spot-scanning proton therapy (RGPT), the dose distribution is distorted by gold fiducial markers placed in the prostate. Distortion can be suppressed by using small markers and more than 2 fields, but additional fields may increase the dose to organs at risk. Therefore, we conducted a prospective study to evaluate the safety and short-term clinical outcome of RGPT for prostate cancer. METHODS AND MATERIALS: Based on the previously reported frequency of early adverse events (AE) and the noninferiority margin of 10%, the required number of cases was calculated to be 43 using the one-sample binomial test by the Southwest Oncology Group statistical tools with the one-sided significance level of 2.5% and the power 80%. Patients with localized prostate cancer were enrolled and 3 to 4 pure gold fiducial markers of 1.5-mm diameter were inserted in the prostate. The prescribed dose was 70 Gy(relative biologic effectiveness) in 30 fractions, and treatment was performed with 3 fields from the left, right, and the back, or 4 fields from either side of slightly anterior and posterior oblique fields. The primary endpoint was the frequency of early AE (≥grade 2) and the secondary endpoint was the biochemical relapse-free survival rate and the frequency of late AE. RESULTS: Forty-five cases were enrolled between 2015 and 2017, and all patients completed the treatment protocol. The median follow-up period was 63.0 months. The frequency of early AE (≥grade 2) was observed in 4 cases (8.9%), therefore the noninferiority was verified. The overall 5-year biochemical relapse-free survival rate was 88.9%. As late AE, grade 2 rectal bleeding was observed in 8 cases (17.8%). CONCLUSIONS: The RGPT for prostate cancer with 1.5-mm markers and 3- or 4- fields was as safe as conventional proton therapy in early AE, and its efficacy was comparable with previous studies.
• A new predictive parameter for dose‐volume metrics in intensity‐modulated radiation therapy planning for prostate cancer: Initial phantom study

  Yuki Saito, Ryusuke Suzuki, Naoki Miyamoto, Kenneth Lee Sutherland, Takahiro Kanehira, Masaya Tamura, Takashi Mori, Kentaro Nishioka, Takayuki Hashimoto, Hidefumi Aoyama

  Journal of Applied Clinical Medical Physics 2024年04月 [査読有り][通常論文]
  
• Probability of normal tissue complications for hematologic and gastrointestinal toxicity in postoperative whole pelvic radiotherapy for gynecologic malignancies using intensity-modulated proton therapy with robust optimization.

  Takaaki Yoshimura, Ryota Yamada, Rumiko Kinoshita, Taeko Matsuura, Takahiro Kanehira, Hiroshi Tamura, Kentaro Nishioka, Koichi Yasuda, Hiroshi Taguchi, Norio Katoh, Keiji Kobashi, Takayuki Hashimoto, Hidefumi Aoyama

  Journal of radiation research 2024年03月17日 

  This retrospective treatment-planning study was conducted to determine whether intensity-modulated proton therapy with robust optimization (ro-IMPT) reduces the risk of acute hematologic toxicity (H-T) and acute and late gastrointestinal toxicity (GI-T) in postoperative whole pelvic radiotherapy for gynecologic malignancies when compared with three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated X-ray (IMXT) and single-field optimization proton beam (SFO-PBT) therapies. All plans were created for 13 gynecologic-malignancy patients. The prescribed dose was 45 GyE in 25 fractions for 95% planning target volume in 3D-CRT, IMXT and SFO-PBT plans and for 99% clinical target volume (CTV) in ro-IMPT plans. The normal tissue complication probability (NTCP) of each toxicity was used as an in silico surrogate marker. Median estimated NTCP values for acute H-T and acute and late GI-T were 0.20, 0.94 and 0.58 × 10-1 in 3D-CRT; 0.19, 0.65 and 0.24 × 10-1 in IMXT; 0.04, 0.74 and 0.19 × 10-1 in SFO-PBT; and 0.06, 0.66 and 0.15 × 10-1 in ro-IMPT, respectively. Compared with 3D-CRT and IMXT plans, the ro-IMPT plan demonstrated significant reduction in acute H-T and late GI-T. The risk of acute GI-T in ro-IMPT plan is equivalent with IMXT plan. The ro-IMPT plan demonstrated potential clinical benefits for reducing the risk of acute H-T and late GI-T in the treatment of gynecologic malignances by reducing the dose to the bone marrow and bowel bag while maintaining adequate dose coverage to the CTV. Our results indicated that ro-IMPT may reduce acute H-T and late GI-T risk with potentially improving outcomes for postoperative gynecologic-malignancy patients with concurrent chemotherapy.
• Impact of adaptive radiotherapy on survival in locally advanced nasopharyngeal carcinoma treated with concurrent chemoradiotherapy.

  Yusuke Uchinami, Koichi Yasuda, Hideki Minatogawa, Yasuhiro Dekura, Noboru Nishikawa, Rumiko Kinoshita, Kentaro Nishioka, Norio Katoh, Takashi Mori, Manami Otsuka, Naoki Miyamoto, Ryusuke Suzuki, Keiji Kobashi, Yasushi Shimizu, Jun Taguchi, Nayuta Tsushima, Satoshi Kano, Akihiro Homma, Hidefumi Aoyama

  Radiation oncology journal 42 1 74 - 82 2024年03月 

  PURPOSE: To investigate the clinical significance of adaptive radiotherapy (ART) in locally advanced nasopharyngeal carcinoma treated with intensity-modulated radiotherapy (IMRT). MATERIALS AND METHODS: Eligible patients were treated with concurrent chemoradiotherapy using IMRT. Planning computed tomography in ART was performed during radiotherapy, and replanning was performed. Since ART was started in May 2011 (ART group), patients who were treated without ART up to April 2011 (non-ART group) were used as the historical control. The Kaplan-Meier method was used to calculate overall survival (OS), locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). LRFS for the primary tumor (LRFS_P) and regional lymph node (LRFS_LN) were also studied for more detailed analysis. Statistical significance was evaluated using the log-rank test for survival. RESULTS: The ART group tended to have higher radiation doses. The median follow-up period was 127 months (range, 10 to 211 months) in the non-ART group and 61.5 months (range, 5 to 129 months) in the ART group. Compared to the non-ART group, the ART group showed significantly higher 5-year PFS (53.8% vs. 81.3%, p = 0.015) and LRFS (61.2% vs. 85.3%, p = 0.024), but not OS (80.7% vs. 80.8%, p = 0.941) and DMFS (84.6% vs. 92.7%, p = 0.255). Five-year LRFS_P was higher in the ART group (61.3% vs. 90.6%, p = 0.005), but LRFS_LN did not show a significant difference (91.9% vs. 96.2%, p = 0.541). CONCLUSION: Although there were differences in the patient backgrounds between the two groups, this study suggests the potential effectiveness of ART in improving locoregional control, especially in the primary tumor.
• Radiotherapy with or without chemotherapy for locally advanced head and neck cancer in elderly patients: analysis of the Head and Neck Cancer Registry of Japan.

  Koichi Yasuda, Yusuke Uchinami, Satoshi Kano, Jun Taguchi, Daisuke Kawakita, Megumi Kitayama, Kentaro Nishioka, Takashi Mori, Fuki Koizumi, Yuri Fujii, Yasushi Shimizu, Keiji Kobashi, Seiichi Yoshimoto, Ken-Ichi Nibu, Akihiro Homma, Hidefumi Aoyama

  International journal of clinical oncology 2023年12月29日 

  BACKGROUND: Whether concurrent chemotherapy with radiotherapy (CRT) is effective for elderly patients with head and neck cancer is a controversial topic. This study aimed to analyze the effectiveness of CRT vs. radiation therapy (RT) among elderly patients in Japan. METHODS: Data from the Head and Neck Cancer Registry of Japan were extracted and analyzed. Patients with locally advanced squamous cell carcinoma of the oropharynx, hypopharynx, or larynx who received definitive CRT or RT between 2011 and 2014 were included. RESULTS: CRT was administered to 78% of the 1057 patients aged ≥ 70 years and 67% of the 555 patients aged ≥ 75 years. For the patients aged ≥ 75 years, the overall survival (OS) rate was significantly better in the CRT group than in the RT group (P < 0.05), while the progression-free survival (PFS) rate was not significantly different (P > 0.05). The add-on effect of CRT was significantly poor in elderly patients (P < 0.05), and it was not a significant factor in the multivariate analysis for patients aged ≥ 75 years. After propensity score matching, there were no significant differences in the OS and PFS rates between the patients aged ≥ 70 years and those aged ≥ 75 years (all, P > 0.05). CONCLUSION: Although aggressive CRT is administered to elderly patients in Japan, its effectiveness is uncertain. Further prospective randomized trials are needed to verify whether CRT is superior to RT alone for elderly patients.
• Daily fraction dose-adjusted radiotherapy policy to avoid prolonging the overall treatment time for early glottic squamous cell carcinoma: a single-institutional retrospective study.

  Yasuhiro Dekura, Koichi Yasuda, Hideki Minatogawa, Yusuke Uchinami, Nayuta Tsushima, Takayoshi Suzuki, Satoshi Kano, Takashi Mori, Kentaro Nishioka, Keiji Kobashi, Norio Katoh, Akihiro Homma, Hidefumi Aoyama

  Journal of radiation research 2023年11月10日 

  The objective of this study was to determine the outcomes of radical radiotherapy for early glottic squamous cell carcinoma (EGSCC) with the policy of increasing the fraction size during radiotherapy when the overall treatment time (OTT) was expected to be prolonged. Patients diagnosed with clinical T1-2N0M0 EGSCC, who were treated with radical radiotherapy between 2008 and 2019 at Hokkaido University Hospital, were included. Patients received 66 Gy in 33 fractions for T1 disease and 70 Gy in 35 fractions for T2 disease as our standard regimen (usual group [UG]). If the OTT was expected to extend for >1 week, the dose fraction size was increased from 2.0 to 2.5 Gy from the beginning or during radiotherapy (adjusted group [AG]). At this time, we performed a statistical analysis between UG and AG. In total, 116 patients were identified, and the treatment schedules of 29 patients were adjusted. The median follow-up was 60.9 months. In the T1 group, the cumulative 5-year local failure rate was 12.0% in the AG and 15.4% in the UG, and in the T2 group, the rate was 40.7% in the AG and 25.3% in the UG. There were no significant differences between the AG and UG. Similarly, no significant differences were observed for overall survival and progression-free survival rates. Our single-institutional retrospective analysis of EGSCC patients suggested that a method of adjusting the radiotherapy schedule to increase fraction size from the beginning or during the course may be effective in maintaining treatment outcomes.
• Slow-growing WNT medulloblastoma with atypical magnetic resonance imaging findings: illustrative case.

  Makoto Mizushima, Michinari Okamoto, Shigeru Yamaguchi, Sogo Oki, Hiroaki Motegi, Minako Sugiyama, Atsushi Manabe, Ai Shimizu, Kentaro Nishioka, Takayuki Hashimoto, Junko Hirato, Yonehiro Kanemura, Miki Fujimura

  Journal of neurosurgery. Case lessons 6 7 2023年08月14日 

  BACKGROUND: Medulloblastomas, with four molecular subgroups, are generally rapid-growing tumors with significant contrast enhancement and well-defined margins. However, each subgroup's clinical features, including disease time course and imaging characteristics, are not well defined. OBSERVATIONS: The authors describe the case of a 15-year-old female who presented with a 7-month history of impaired left-hand movement and was found to have a lesion on the dorsal side of the fourth ventricle. T2-weighted magnetic resonance imaging (MRI) at the patient's first presentation showed diffuse hyperintense signal without apparent mass, and gadolinium-enhanced T1-weighted imaging showed very slight contrast enhancement. In 1 month, her symptoms progressed, and follow-up MRI revealed an increase in the size of the lesion, showing greater diffusion restriction and contrast enhancement. She underwent gross-total resection, and pathology was consistent with classic medulloblastoma. Genetic analysis of the tumor confirmed the wingless (WNT) molecular subgroup. Adjuvant chemotherapy and proton beam therapy were performed. At the 18-month follow-up, MRI showed no recurrence of disease. LESSONS: Slow-growing medulloblastoma is very rare and not known to be associated with a specific molecular subgroup. Here, the authors report a case of slow-growing WNT medulloblastoma, indicating that slow growth may be a feature of this subgroup.
• Predicting the daily gastrointestinal doses of stereotactic body radiation therapy for pancreatic cancer based on the shortest distance between the tumor and the gastrointestinal tract using daily computed tomography images

  Yusuke Uchinami, Takahiro Kanehira, Keiji Nakazato, Yoshihiro Fujita, Fuki Koizumi, Shuhei Takahashi, Manami Otsuka, Koichi Yasuda, Hiroshi Taguchi, Kentaro Nishioka, Naoki Miyamoto, Kohei Yokokawa, Ryusuke Suzuki, Keiji Kobashi, Keita Takahashi, Norio Katoh, Hidefumi Aoyama

  BJR|Open 5 1 2023年08月 

  Objectives: We aimed to investigate whether daily computed tomography (CT) images could predict the daily gastroduodenal, small intestine, and large intestine doses of stereotactic body radiation therapy (SBRT) for pancreatic cancer based on the shortest distance between the gross tumor volume (GTV) and gastrointestinal (GI) tract. Methods: Twelve patients with pancreatic cancer received SBRT of 40 Gy in five fractions. We recalculated the reference clinical SBRT plan (PLAN_ref) using daily CT images and calculated the shortest distance from the GTV to each GI tract. The maximum dose delivered to 0.5 cc (D_0.5cc) was evaluated for each planning at-risk volume of the GI tract. Spearman’s correlation test was used to determine the association between the daily change in the shortest distance (Δshortest distance) and the ratio of ΔD_0.5cc dose to D_0.5cc dose in PLAN_ref (ΔD_0.5cc/PLAN_ref) for quantitative analysis. Results: The median shortest distance in PLAN_ref was 0 mm in the gastroduodenum (interquartile range, 0–2.7), 16.7 mm in the small intestine (10.0–23.7), and 16.7 mm in the large intestine (8.3–28.1 mm). The D_0.5cc of PLAN_ref in the gastroduodenum was >30 Gy in all patients, with 10 (83.3%) having the highest dose. A significant association was found between the Δshortest distance and ΔD_0.5cc/ PLAN_ref in the small or large intestine (p < 0.001) but not in the gastroduodenum (p = 0.404). Conclusions: The gastroduodenum had a higher D_0.5cc and predicting the daily dose was difficult. Daily dose calculations of the GI tract are recommended for safe SBRT. Advances in knowledge: This study aimed to predict the daily doses in SBRT for pancreatic cancer from the shortest distance between the GTV and the gastrointestinal tract. Daily changes in the shortest distance can predict the daily dose to the small or large intestines, but not to the gastroduodenum.
• Proton beam therapy for muscle-invasive bladder cancer: A systematic review and analysis with Proton-Net, a multicenter prospective patient registry database.

  Masayuki Araya, Hitoshi Ishikawa, Kentaro Nishioka, Kazushi Maruo, Hirofumi Asakura, Takashi Iizumi, Masaru Takagi, Masao Murakami, Haruhito Azuma, Wataru Obara, Hidefumi Aoyama, Hideyuki Sakurai

  Journal of radiation research 2023年04月25日 

  To assess the safety and efficacy of proton beam therapy (PBT) for muscle-invasive bladder cancer (MIBC), we examined the outcomes of 36 patients with MIBC (cT2-4aN0M0) who were enrolled in the Proton-Net prospective registry study and received PBT with concurrent chemotherapy from May 2016 to June 2018. PBT was also compared with X-ray chemoradiotherapy in a systematic review (X-ray (photon) radiotherapy). The radiotherapy consisted of 40-41.4 Gy (relative biological effectiveness (RBE) delivered in 20-23 fractions to the pelvic cavity or the entire bladder using X-rays or proton beams, followed by a boost of 19.8-36.3 Gy (RBE) delivered in 10-14 fractions to all tumor sites in the bladder. Concurrently, radiotherapy was given with intra-arterial or systemic chemotherapy of cisplatin alone or in combination with methotrexate or gemcitabine. Overall survival (OS), progression-free survival (PFS) and local control (LC) rates were 90.8, 71.4 and 84.6%, respectively, after 3 years. Only one case (2.8%) experienced a treatment-related late adverse event of Grade 3 urinary tract obstruction, and no severe gastrointestinal adverse events occurred. According to the findings of the systematic review, the 3-year outcomes of XRT were 57-84.8% in OS, 39-78% in PFS and 51-68% in LC. The weighted mean frequency of adverse events of Grade 3 or higher in the gastrointestinal and genitourinary systems was 6.2 and 2.2%, respectively. More data from long-term follow-up will provide us with the appropriate use of PBT and validate its efficacy for MIBC.
• The need of radiotherapy optimization for glioblastomas considering immune responses.

  Kentaro Nishioka, Shuhei Takahashi, Takashi Mori, Yusuke Uchinami, Shigeru Yamaguchi, Manabu Kinoshita, Masaaki Yamashina, Hajime Higaki, Katsuya Maebayashi, Hidefumi Aoyama

  Japanese journal of radiology 2023年04月18日 

  Glioblastoma is the most common of malignant primary brain tumors and one of the tumors with the poorest prognosis for which the overall survival rate has not significantly improved despite recent advances in treatment techniques and therapeutic drugs. Since the emergence of immune checkpoint inhibitors, the immune response to tumors has attracted increasing attention. Treatments affecting the immune system have been attempted for various tumors, including glioblastomas, but little has been shown to be effective. It has been found that the reason for this is that glioblastomas have a high ability to evade attacks from the immune system, and that the lymphocyte depletion associated with treatment can reduce its immune function. Currently, research to elucidate the resistance of glioblastomas to the immune system and development of new immunotherapies are being vigorously carried out. Targeting of radiation therapy for glioblastomas varies among guidelines and clinical trials. Based on early reports, target definitions with wide margins are common, but there are also reports that narrowing the margins does not make a significant difference in treatment outcome. It has also been suggested that a large number of lymphocytes in the blood are irradiated by the irradiation treatment to a wide area in a large number of fractionations, which may reduce the immune function, and the blood is being recognized as an organ at risk. Recently, a randomized phase II trial comparing two types of target definition in radiotherapy for glioblastomas was conducted, and it was reported that the overall survival and progression-free survival were significantly better in a small irradiation field group. We review recent findings on the immune response and the immunotherapy to glioblastomas and the novel role of radiotherapy and propose the need to develop an optimal radiotherapy that takes radiation effects on the immune function into account.
• A Japanese registry study and systematic review of particle therapy for renal cell carcinoma.

  Hitoshi Ishikawa, Takeshi Arimura, Kazushi Maruo, Hidemasa Kawamura, Shingo Toyama, Takashi Ogino, Tomoaki Okimoto, Masao Murakami, Yoshitaka Sato, Kentaro Nishioka, Masayuki Araya, Hisateru Ohba, Kensuke Umehara, Hidefumi Aoyama, Wataru Obara, Haruhito Azuma, Hiroshi Tsuji, Hideyuki Sakurai

  Journal of radiation research 2023年04月12日 

  The feasibility and efficacy of particle beam therapy (PBT) using protons or carbon ions were compared with those of photon-based stereotactic body radiotherapy (SBRT) for primary renal cell carcinoma (RCC) via a systematic review and nationwide registry for PBT (Japanese Society for Radiation Oncology [JASTRO] particle therapy committee). Between July 2016 and May 2019, 20 patients with non-metastatic RCC who were treated at six Japanese institutes (using protons at three, using carbon ions at the other three) were registered in the nationwide database and followed up prospectively. The 20 patients comprised 15 men and had a median age of 67 (range: 57-88) years. The total radiation dose was 66-79.6 Gy (relative biological effectiveness [RBE]). Over a median follow up of 31 months, the 3-year rates of overall survival (OS) and local control (LC) were 100% and 94.4%, respectively. No grade ≥ 3 toxicities were observed. Based on a random effects model, a meta-analysis including the present results revealed 3-year OS rates after SBRT and PBT of 75.3% (95% CI: 57.3-86.6) and 94.3% (95% CI: 86.8-97.6), respectively (P = 0.005), but the difference in LC rates between the two methods was not observed (P = 0.63). PBT is expected to have similar if not better treatment results compared with SBRT for primary renal cancer. In particular, PBT was shown to be effective even for large RCC and could provide a therapeutic option when SBRT is not indicated.
• Proton beam therapy for gliomas: a multicenter prospective registry study from all proton beam facilities in Japan

  Takashi Mori, Masashi Mizumoto, Katsuya Maebayashi, Kentaro Nishioka, Yoshiki Arakawa, Kazuhiko Kurozumi, Koichi Yasuda, Taisuke Sumiya, Hiroyasu Tamamura, Yoshitaka Sato, Takahiro Waki, Masaru Takagi, Yu Takada, Tomoaki Okimoto, Masao Murakami, Yasuhiro Kikuchi, Kazufumi Okada, Yoichi M Ito, Tetsuo Akimoto, Hidefumi Aoyama

  Journal of Radiation Research 2023年04月07日 

  Abstract We reviewed the outcomes of glioma patients enrolled in a prospective observational registry study of proton beam therapy (PBT) in Japan. The inclusion criteria were glioma patients registered in the Electronic Data Capture system, the Proton-net, between May 2016 and July 2019. Data on patient characteristics, treatments, late adverse events, survival status, recurrence and secondary tumors were extracted and statistically analyzed. The primary endpoint was the overall survival (OS) rate, and the secondary endpoints were the progression-free survival (PFS) rate and cumulative local recurrence rate (cLRR). Of the 65 primary brain tumor patients registered, 29 glioma patients from eight of 19 PBT facilities met the inclusion criteria. There were 19 glioblastoma patients, eight of other malignant gliomas, and two of low-grade gliomas. For glioblastomas, with a median follow-up period of 16 months, the median survival time was 21.2 months and the OS at 1, 2, 3 and 4 years were 77.4%, 44.9%, 23.9% and 23.9%, respectively. The median PFS period was 10.1 months, the 1, 2, 3 and 4-year PFS were 32.4%, 19.4%, 9.7% and 9.7%, respectively. The 1, 2, 3 and 4-year cLRR were 56.1%, 68.8%, 78.4 and 78.4%, respectively. Grade 3 brain necrosis was observed in two patients. No secondary tumor was observed. This is the first report on the current status of PBT for gliomas in Japan. For glioblastomas, the outcomes of PBT are estimated to be equivalent to historical data of photon therapy. The results of a prospective comparative evaluation of PBT and photon therapy are awaited.
• Brain metastases in Japanese NSCLC patients: prognostic assessment and the use of osimertinib and immune checkpoint inhibitors-retrospective study.

  Hajime Higaki, Kentaro Nishioka, Manami Otsuka, Noboru Nishikawa, Motoyasu Shido, Hideki Minatogawa, Yukiko Nishikawa, Rikiya Takashina, Takayuki Hashimoto, Norio Katoh, Hiroshi Taguchi, Rumiko Kinoshita, Koichi Yasuda, Takashi Mori, Yusuke Uchinami, Fuki Koizumi, Yoshihiro Fujita, Shuhei Takahashi, Takahiro Hattori, Noriaki Nishiyama, Hidefumi Aoyama

  Radiation oncology (London, England) 18 1 25 - 25 2023年02月07日 

  BACKGROUND: The Graded Prognostic Assessment for lung cancer using molecular markers (Lung-molGPA) has not been validated for use with Japanese non-small cell lung cancer (NSCLC) patients with brain metastasis (BM) and the factors impacting survival need to be assessed. METHODS: We retrospectively analyzed 294 NSCLC patients who were newly diagnosed with BM between 2013 and 2020 and had received radiotherapy for BM initially at the Hokkaido Cancer Center. We evaluated the effect on the prognosis of Lung-molGPA items, the expression of PD-L1 (classified as high, low, and no expression), and the treatment history. The main outcome was the survival measured from the day of the diagnosis of BM, and log-rank tests were performed to evaluate the results. RESULTS: The median overall survival (OS) times for adenocarcinoma by groups of GPA scores (0‒1.0, 1.5‒2.0, 2.5‒3.0, and 3.5‒4.0) were 5.5, 14.8, 28.3, and 39.0 months (p < 0.0001), respectively. The median survival times for non-adenocarcinoma by groups of GPA scores (0‒1.0, 1.5‒2.0, and 2.5‒3.0) were 3.2, 11.0, and 16.0 months (p = 0.0011), respectively. In adenocarcinoma patients with gene mutations, osimertinib significantly improved the outcome (median OS: 34.2 and 17.6 months with and without osimertinib, respectively (p = 0.0164)). There was no significant difference in the OS between patients who were initially treated with tyrosine-kinase inhibitor for BM and those who initially received radiotherapy (p = 0.5337). In patients tested for PD-L1 expression, the median survival times after the diagnosis of BM were 5.6, 22.5, and 9.3 months for the high-, low- and no-expression groups (p = 0.2198), respectively. Also, in patients with high PD-L1 expressions, those with ICI had survival (median OS, 8.6 months) than those without (median OS, 3.6 months). CONCLUSIONS: We confirmed that Lung-molGPA successfully classified Japanese NSCLC patients with BM by the prognosis. Osimertinib prolonged survival of EGFR-positive NSCLC patients with BM, and ICI was effective in patients with high PD-L1 expressions.
• Distribution of human papilloma virus genotypes and treatment outcomes in definitive radiotherapy for cervical cancer.

  Rumiko Kinoshita, Takashi Mitamura, Fumi Kato, Takahiro Hattori, Hajime Higaki, Shuhei Takahashi, Yoshihiro Fujita, Manami Otsuka, Fuki Koizumi, Yusuke Uchinami, Takashi Mori, Kentaro Nishioka, Takayuki Hashimoto, Yoichi M Ito, Hidemichi Watari, Hidefumi Aoyama

  Journal of radiation research 64 2 463 - 470 2023年01月03日 

  Most oncogenic human papilloma virus (HPV) genotypes stratify into two species, α-7 HPV and α-9 HPV. There are several studies that evaluate the relationship between HPV species and treatment outcomes and reports that HPV species is prognostic. The HPV genotyping was conducted using biopsy specimens which had been stored in these studies. We conducted the study using the HPV test performed by cytology specimens which is less invasive and more useful in clinical settings. This study enrolled 46 patients who received HPV genotyping before the definitive radiotherapy. The results of the HPV genotyping were classified into HPVα-7, HPVα-9 and negatives. Of the 46 patients, 10 were positive for HPVα-7, 21 positive for HPVα-9 and 15 were negative. The median follow-up period was 38 months (range 4-142). The HPVα-7, HPVα-9 and negative groups showed the 3-year overall survival (OS; 59.3%, 80.4% and 72.2% [P = 0.25]); local control (LC; 67.5%, 81% and 80% [P = 0.78]); pelvic control (PC) (50%, 81% and 72.7% [P = 0.032]); pelvic lymph node (PLN) control (78.7%, 95% and 92.3% [P = 0.012]); distant metastasis free (DMF) survival (50%, 75.4% and 42.8% [P = 0.098]); and progression free survival (PFS) rate of patients (30%, 66.7% and 38.9% [P = 0.085]), respectively. Patients with HPVα-7 showed statistically significant poorer PC than the HPVα-9 group, in multivariate analysis. This result is consistent with previous studies for HPV positive patients. The HPV negativity rate was higher in this study than in other studies and further work on this may be needed for clinical use.
• Radiotherapy for ductal carcinoma of the prostate: an analysis based on the Japanese radiation oncology study group survey

  Kentaro Nishioka

  Japanese Journal of Clinical Oncology 2023年
• Prostatic urinary tract visualization with super-resolution deep learning models.

  Takaaki Yoshimura, Kentaro Nishioka, Takayuki Hashimoto, Takashi Mori, Shoki Kogame, Kazuya Seki, Hiroyuki Sugimori, Hiroko Yamashina, Yusuke Nomura, Fumi Kato, Kohsuke Kudo, Shinichi Shimizu, Hidefumi Aoyama

  PloS one 18 1 e0280076  2023年 

  In urethra-sparing radiation therapy, prostatic urinary tract visualization is important in decreasing the urinary side effect. A methodology has been developed to visualize the prostatic urinary tract using post-urination magnetic resonance imaging (PU-MRI) without a urethral catheter. This study investigated whether the combination of PU-MRI and super-resolution (SR) deep learning models improves the visibility of the prostatic urinary tract. We enrolled 30 patients who had previously undergone real-time-image-gated spot scanning proton therapy by insertion of fiducial markers. PU-MRI was performed using a non-contrast high-resolution two-dimensional T2-weighted turbo spin-echo imaging sequence. Four different SR deep learning models were used: the enhanced deep SR network (EDSR), widely activated SR network (WDSR), SR generative adversarial network (SRGAN), and residual dense network (RDN). The complex wavelet structural similarity index measure (CW-SSIM) was used to quantitatively assess the performance of the proposed SR images compared to PU-MRI. Two radiation oncologists used a 1-to-5 scale to subjectively evaluate the visibility of the prostatic urinary tract. Cohen's weighted kappa (k) was used as a measure of agreement of inter-operator reliability. The mean CW-SSIM in EDSR, WDSR, SRGAN, and RDN was 99.86%, 99.89%, 99.30%, and 99.67%, respectively. The mean prostatic urinary tract visibility scores of the radiation oncologists were 3.70 and 3.53 for PU-MRI (k = 0.93), 3.67 and 2.70 for EDSR (k = 0.89), 3.70 and 2.73 for WDSR (k = 0.88), 3.67 and 2.73 for SRGAN (k = 0.88), and 4.37 and 3.73 for RDN (k = 0.93), respectively. The results suggest that SR images using RDN are similar to the original images, and the SR deep learning models subjectively improve the visibility of the prostatic urinary tract.
• Detailed analysis of failure patterns using deformable image registration in hypopharyngeal cancer patients treated with sequential boost intensity-modulated radiotherapy.

  Manami Otsuka, Koichi Yasuda, Yusuke Uchinami, Nayuta Tsushima, Takayoshi Suzuki, Satoshi Kano, Ryusuke Suzuki, Naoki Miyamoto, Hideki Minatogawa, Yasuhiro Dekura, Takashi Mori, Kentaro Nishioka, Jun Taguchi, Yasushi Shimizu, Norio Katoh, Akihiro Homma, Hidefumi Aoyama

  Journal of medical imaging and radiation oncology 67 1 98 - 110 2022年11月14日 [査読有り]
   

  INTRODUCTION: Sequential boost intensity-modulated radiotherapy (SQB-IMRT) uses two different planning CTs (pCTs) and treatment plans. SQB-IMRT is a form of adaptive radiotherapy that allows for responses to changes in the shape of the tumour and organs at risk (OAR). On the other hand, dose accumulation with the two plans can be difficult to evaluate. The purpose of this study was to analyse patterns of loco-regional failure using deformable image registration (DIR) in hypopharyngeal cancer patients treated with SQB-IMRT. METHODS: Between 2013 and 2019, 102 patients with hypopharyngeal cancer were treated with definitive SQB-IMRT at our institution. Dose accumulation with the 1st and 2nd plans was performed, and the dose to the loco-regional recurrent tumour volume was calculated using the DIR workflow. Failure was classified as follows: (i) in-field (≥95% of the recurrent tumour volume received 95% of the prescribed dose); (ii) marginal (20-95%); or (iii) out-of-field (<20%). RESULTS: After a median follow-up period of 25 months, loco-regional failure occurred in 34 patients. Dose-volume histogram analysis showed that all loco-regional failures occurred in the field within 95% of the prescribed dose, with no marginal or out-of-field recurrences observed. CONCLUSION: The dosimetric analysis using DIR showed that all loco-regional failures were within the high-dose region. More aggressive treatment may be required for gross tumours.
• 放射線治療を中心としたがん治療について-最近の変化と将来- 膠芽腫に対する免疫反応を考慮した照射野最適化の必要性

  西岡 健太郎, 高橋 周平, 森 崇, 打浪 雄介, 山口 秀, 木下 学, 山品 将祥, 前林 勝也, 青山 英史

  日本医学放射線学会秋季臨床大会抄録集 58回 S345 - S345 (公社)日本医学放射線学会 2022年08月
• A study on predicting cases that would benefit from proton beam therapy in primary liver tumors of less than or equal to 5 cm based on the estimated incidence of hepatic toxicity.

  Yusuke Uchinami, Norio Katoh, Ryusuke Suzuki, Takahiro Kanehira, Masaya Tamura, Seishin Takao, Taeko Matsuura, Naoki Miyamoto, Yoshihiro Fujita, Fuki Koizumi, Hiroshi Taguchi, Koichi Yasuda, Kentaro Nishioka, Isao Yokota, Keiji Kobashi, Hidefumi Aoyama

  Clinical and translational radiation oncology 35 70 - 75 2022年07月 [査読有り]
   

  Background: For small primary liver tumors, favorable outcomes have been reported with both of proton beam therapy (PBT) and X-ray therapy (XRT). However, no clear criteria have been proposed in the cases for which and when of PBT or XRT has to be used. The aim of this study is to investigate cases that would benefit from PBT based on the predicted rate of hepatic toxicity. Materials and methods: Eligible patients were those who underwent PBT for primary liver tumors with a maximum diameter of ≤ 5 cm and Child-Pugh grade A (n = 40). To compare the PBT-plan, the treatment plan using volumetric modulated arc therapy was generated as the XRT-plan. The rate of predicted hepatic toxicity was estimated using five normal tissue complication probability (NTCP) models with three different endpoints. The differences in NTCP values (ΔNTCP) were calculated to determine the relative advantage of PBT. Factors predicting benefits of PBT were analyzed by logistic regression analysis. Results: From the dose-volume histogram comparisons, an advantage of PBT was found in sparing of the normal liver receiving low doses. The factors predicting the benefit of PBT differed depending on the selected NTCP model. From the five models, the total tumor diameter (sum of the target tumors), location (hepatic hilum vs other), and number of tumors (1 vs 2) were significant factors. Conclusions: From the radiation-related hepatic toxicity, factors were identified to predict benefits of PBT in primary liver tumors with Child-Pugh grade A, with the maximum tumor diameter of ≤ 5 cm.
• 北海道大学病院放射線治療科関連施設における子宮頸癌に対する根治放射線治療に関するアンケート結果について

  木下 留美子, 打浪 雄介, 高橋 周平, 小泉 富基, 森 崇, 西岡 健太郎, 田口 大志, 橋本 孝之, 高邑 明夫, 西岡 井子, 北原 利博, 土屋 和彦, 井上 哲也, 有本 卓郎, 出倉 康裕, 米坂 祥朗, 鈴木 恵士郎, 川島 和之, 小野寺 俊輔, 喜多村 圭, 長谷川 雅一, 鬼丸 力也, 富田 雅義, 池田 潤, 西山 典明, 青山 英史

  北海道放射線医学雑誌 2 13 - 18 (NPO)メディカルイメージラボ 2022年03月 [査読有り]
   

  子宮頸癌に対する根治的放射線治療において子宮内から照射を行う腔内照射は必要不可欠な要素である。腔内照射の設備の維持・更新および子宮頸癌根治照射人数等について北海道大学病院放射線治療科関連病院にアンケートを行った。道内の施設の子宮頸癌根治照射人数は年間10人以下の施設が大半で、腔内照射設備を保有している施設の年間の腔内照射人数は5-9人が4施設、10人以上が2施設であった。腔内照射設備を保有している6施設の内4施設で設備の維持・更新が採算面で難しいという理由で腔内照射の休止を検討している事が明らかとなった。北海道内の子宮頸癌に対する根治照射を継続して行うためには、腔内照射設備を持つ施設への適切な紹介システムの構築と腔内照射が可能な施設の地域性を考慮した適切な集約化が必要と考えられた。(著者抄録)
• HyperArcを用いた多発性脳転移腫瘍に対する脳定位放射線治療中の各標的の位置ずれに関する検討

  山田 亮太, 吉村 高明, 若林 倭, 金平 孝博, 森 崇, 西岡 健太郎, 青山 英史

  日本放射線技術学会総会学術大会予稿集 78回 161 - 162 (公社)日本放射線技術学会 2022年03月
• Dosimetric advantages of daily adaptive strategy in IMPT for high-risk prostate cancer.

  Hiroshi Tamura, Keiji Kobashi, Kentaro Nishioka, Takaaki Yoshimura, Takayuki Hashimoto, Shinichi Shimizu, Yoichi M Ito, Yoshikazu Maeda, Makoto Sasaki, Kazutaka Yamamoto, Hiroyasu Tamamura, Hidefumi Aoyama, Hiroki Shirato

  Journal of applied clinical medical physics 23 4 e13531  2022年01月19日 [査読有り]
   

  PURPOSE: To evaluate the dosimetric advantages of daily adaptive radiotherapy (DART) in intensity-modulated proton therapy (IMPT) for high-risk prostate cancer by comparing estimated doses of the conventional non-adaptive radiotherapy (NART) that irradiates according to an original treatment plan through the entire treatment and the DART that uses an adaptive treatment plan generated by using daily CT images acquired before each treatment. METHODS: Twenty-three patients with prostate cancer were included. A treatment plan with 63 Gy (relative biological effectiveness (RBE)) in 21 fractions was generated using treatment planning computed tomography (CT) images assuming that all patients had high-risk prostate cancer for which the clinical target volume (CTV) needs to include prostate and the seminal vesicle (SV) in our treatment protocol. Twenty-one adaptive treatment plans for each patient (total 483 data sets) were generated using daily CT images, and dose distributions were calculated. Using a 3 mm set-up uncertainty in the robust optimization, the doses to the CTV, prostate, SV, rectum, and bladder were compared. RESULTS: Estimated accumulated doses of NART and DART in the 23 patients were 60.81 ± 3.47 Gy (RBE) and 63.24 ± 1.04 Gy (RBE) for CTV D99 (p < 0.01), 62.99 ± 1.28 Gy (RBE) and 63.43 ± 1.33 Gy (RBE) for the prostate D99 (p = 0.2529), and 59.07 ± 5.19 Gy (RBE) and 63.17 ± 1.04 Gy (RBE) for SV D99 (p < 0.001). No significant differences were observed between NART and DART in the estimated accumulated dose for the rectum and bladder. CONCLUSION: Compared with the NART, DART was shown to be a useful approach that can maintain the dose coverage to the target without increasing the dose to the organs at risk (OAR) using the 3 mm set-up uncertainty in the robust optimization in patients with high-risk prostate cancer.
• Treatment Planning to Suppress Sublethal-Damage Repair by Modulating Spatio-Temporal Patterns of Spot-Scanning Proton Dose Delivery: An Initial Study

  Kentaro Nishioka

  Medical Physics 2022年
• Feasibility Study of Proton Scanning System with Perpendicular Magnetic Field by Open MRI

  Kentaro Nishioka

  Medical Physics 2022年
• Impact of a spatially dependent dose delivery time structure on the biological effectiveness of scanning proton therapy.

  Koki Kasamatsu, Sodai Tanaka, Koichi Miyazaki, Seishin Takao, Naoki Miyamoto, Shusuke Hirayama, Kentaro Nishioka, Takayuki Hashimoto, Hidefumi Aoyama, Kikuo Umegaki, Taeko Matsuura

  Medical physics 49 1 702 - 713 2022年01月 [査読有り]
   

  PURPOSE: In the scanning beam delivery of protons, different portions of the target are irradiated with different linear energy transfer protons with various time intervals and irradiation times. This research aimed to evaluate the spatially dependent biological effectiveness of protracted irradiation in scanning proton therapy. METHODS: One and two parallel opposed fields plans were created in water phantom with the prescribed dose of 2 Gy. Three scenarios (instantaneous, continuous, and layered scans) were used with the corresponding beam delivery models. The biological dose (physical dose × relative biological effectiveness) was calculated using the linear quadratic model and the theory of dual radiation action to quantitatively evaluate the dose delivery time effect. In addition, simulations using clinical plans (postoperative seminoma and prostate tumor cases) were conducted to assess the impact of the effects on the dose volume histogram parameters and homogeneity coefficient (HC) in targets. RESULTS: In a single-field plan of water phantom, when the treatment time was 19 min, the layered-scan scenario showed a decrease of <0.2% (almost 3.3%) in the biological dose from the plan on the distal (proximal) side because of the high (low) dose rate. This is in contrast to the continuous scenario, where the biological dose was almost uniformly decreased over the target by approximately 3.3%. The simulation with clinical geometry showed that the decrease rates in D99% were 0.9% and 1.5% for every 10 min of treatment time prolongation for postoperative seminoma and prostate tumor cases, respectively, whereas the increase rates in HC were 0.7% and 0.2%. CONCLUSIONS: In protracted irradiation in scanning proton therapy, the spatially dependent dose delivery time structure in scanning beam delivery can be an important factor for accurate evaluation of biological effectiveness.
• Evaluation of Visualizing the Prostatic Urinary Tract in MRI With a Super Resolution Deep Learning Model for Urethra Sparing Radiotherapy

  T. Yoshimura, K. Nishioka, T. Hashimoto, S. Kogame, K. Seki, H. Sugimori, H. Yamashina, F. Kato, H. Aoyama, K. Kudo, S. Shimizu

  International Journal of Radiation Oncology*Biology*Physics 111 3 e121 - e122 2021年11月
• A treatment planning study of urethra-sparing intensity-modulated proton therapy for localized prostate cancer

  Takaaki Yoshimura, Kentaro Nishioka, Takayuki Hashimoto, Kazuya Seki, Shouki Kogame, Sodai Tanaka, Takahiro Kanehira, Masaya Tamura, Seishin Takao, Taeko Matsuura, Keiji Kobashi, Fumi Kato, Hidefumi Aoyama, Shinichi Shimizu

  Physics and Imaging in Radiation Oncology 20 23 - 29 2021年10月 [査読有り]
   

  BACKGROUND AND PURPOSE: Urethra-sparing radiation therapy for localized prostate cancer can reduce the risk of radiation-induced genitourinary toxicity by intentionally underdosing the periurethral transitional zone. We aimed to compare the clinical impact of a urethra-sparing intensity-modulated proton therapy (US-IMPT) plan with that of conventional clinical plans without urethral dose reduction. MATERIALS AND METHODS: This study included 13 patients who had undergone proton beam therapy. The prescribed dose was 63 GyE in 21 fractions for 99% of the clinical target volume. To compare the clinical impact of the US-IMPT plan with that of the conventional clinical plan, tumor control probability (TCP) and normal tissue complication probability (NTCP) were calculated with a generalized equivalent uniform dose-based Lyman-Kutcher model using dose volume histograms. The endpoints of these model parameters for the rectum, bladder, and urethra were fistula, contraction, and urethral stricture, respectively. RESULTS: The mean NTCP value for the urethra in US-IMPT was significantly lower than that in the conventional clinical plan (0.6% vs. 1.2%, p < 0.05). There were no statistically significant differences between the conventional and US-IMPT plans regarding the mean minimum dose for the urethra with a 3-mm margin, TCP value, and NTCP value for the rectum and bladder. Additionally, the target dose coverage of all plans in the robustness analysis was within the clinically acceptable range. CONCLUSIONS: Compared with the conventional clinically applied plans, US-IMPT plans have potential clinical advantages and may reduce the risk of genitourinary toxicities, while maintaining the same TCP and NTCP in the rectum and bladder.
• 再照射 小児がんに対する陽子線再照射

  橋本 孝之, 森 崇, 西岡 健太郎, 打浪 雄介, 安田 耕一, 木下 留美子, 田口 大志, 加藤 徳雄, 清水 伸一, 青山 英史

  日本小児血液・がん学会雑誌 58 2 89 - 93 (一社)日本小児血液・がん学会 2021年08月 

  陽子線治療は通常のX線による放射線治療に比べて線量集中性に優れ,標的への線量を保ったまま周囲の正常組織線量を低減することで,小児がん患者の急性期並びに晩期有害事象の軽減が可能である.2016年4月からは20歳未満の限局性固形悪性腫瘍に対する根治的な陽子線照射が保険適応となり,各施設で小児がんの陽子線治療実施件数が増加傾向にある.局所領域再発に対する再照射は,腫瘍進行抑制・症状緩和と,時に治癒や長期の腫瘍制御による健康状態・QOLの維持をもたらす可能性がある.小児患者に対する再照射における重要臓器・器官の累積耐容線量や安全性は確立していないが,中枢神経腫瘍に対する陽子線再照射により,有害事象の発生を抑えた良好な治療成績が報告されている.今後,小児がん再発の治療選択肢における陽子線再照射の有用性については,前向き臨床試験での評価が必要と考える.(著者抄録)
• 再照射 小児がんに対する陽子線再照射

  橋本 孝之, 森 崇, 西岡 健太郎, 打浪 雄介, 安田 耕一, 木下 留美子, 田口 大志, 加藤 徳雄, 清水 伸一, 青山 英史

  日本小児血液・がん学会雑誌 58 2 89 - 93 (一社)日本小児血液・がん学会 2021年08月
• Treatment outcomes of stereotactic body radiation therapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinomas.

  Yusuke Uchinami, Norio Katoh, Daisuke Abo, Hiroshi Taguchi, Koichi Yasuda, Kentaro Nishioka, Takeshi Soyama, Ryo Morita, Naoki Miyamoto, Ryusuke Suzuki, Takuya Sho, Masato Nakai, Koji Ogawa, Tatsuhiko Kakisaka, Tatsuya Orimo, Toshiya Kamiyama, Shinichi Shimizu, Hidefumi Aoyama

  Hepatology research : the official journal of the Japan Society of Hepatology 51 8 870 - 879 2021年08月 [査読有り]
   

  AIM: To report the outcomes of stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinoma patients. METHODS: From January 2005 to July 2018, 63 patients with 74 lesions with a maximum diameter ≤52 mm were treated by stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system. No patient with a Child-Pugh Score ≥9 was included, and 85.6% had a score of 5 or 6. Using the biological effective dose (BED) with an α/β ratio of 10 (BED10 ), the median dose in BED10 at the reference point was 76.8 Gy (range 60-122.5 Gy). Overall survival (OS) and local control rates were assessed using the Kaplan-Meier method. RESULTS: With a median follow-up period of 24.6 months (range 0.9-118.4 months), the 1-year and 2-year OS rates were 86.8% (95% confidence interval [95% CI] 75.8-93.3) and 71.1% (57.8-81.6), respectively. The 2-year OS was 89.6% in patients with the baseline modified albumin-bilirubin (mALBI) grade =1, and 61.7% in patients with grade ≥2a. In the multivariate analysis, the mALBI grade (=1 vs. ≥2a) was a significant factor for OS (p = 0.028, 95% CI 1.11-6.18). The 1-year and 2-year local control rates were 100% (100-100%) and 92.0% (77.5-97.5%). The local control rates were significantly higher in the BED10 ≥100 Gy group than in the BED10 <100 Gy group (2-year 100% vs. 86.5%, p = 0.049) at the reference point. CONCLUSION: This retrospective study of stereotactic body radiotherapy using real-time tumor-tracking radiotherapy for hepatocellular carcinoma showed favorable outcomes with lower incidence of toxicities, especially in patients treated with BED10 ≥100 Gy to the reference point.
• 泌尿器癌に対する局所療法-超高齢社会の先端医療のあり方は? 筋層浸潤性膀胱癌に対する集学的治療 化学放射線療法による膀胱温存について

  安部 崇重, 宮田 遥, 山田 修平, 菊地 央, 松本 隆児, 大澤 崇宏, 西岡 健太郎, 橋本 孝之, 清水 伸一, 篠原 信雄

  日本老年泌尿器科学会誌 34 1 50 - 50 日本老年泌尿器科学会 2021年04月
• Visualizing the urethra by magnetic resonance imaging without usage of a catheter for radiotherapy of prostate cancer.

  Takaaki Yoshimura, Kentaro Nishioka, Takayuki Hashimoto, Taro Fujiwara, Kinya Ishizaka, Hiroyuki Sugimori, Shoki Kogame, Kazuya Seki, Hiroshi Tamura, Sodai Tanaka, Yuto Matsuo, Yasuhiro Dekura, Fumi Kato, Hidefumi Aoyama, Shinichi Shimizu

  Physics and imaging in radiation oncology 18 1 - 4 2021年04月 [査読有り]
   

  The urethra position may shift due to the presence/absence of the catheter. Our proposed post-urination-magnetic resonance imaging (PU-MRI) technique is possible to identify the urethra without catheter. We aimed to verify the inter-operator difference in contouring the urethra by PU-MRI. The mean values of the evaluation indices of dice similarity coefficient, mean slice-wise Hausdorff distance, and center coordinates were 0.93, 0.17 mm, and 0.36 mm for computed tomography, and 0.75, 0.44 mm, and 1.00 mm for PU-MRI. Therefore, PU-MRI might be useful for identifying the prostatic urinary tract without using a urethral catheter. Clinical trial registration: Hokkaido University Hospital for Clinical Research (018-0221).
• Analysis of acute-phase toxicities of intensity-modulated proton therapy using a model-based approach in pharyngeal cancer patients.

  Koichi Yasuda, Hideki Minatogawa, Yasuhiro Dekura, Seishin Takao, Masaya Tamura, Nayuta Tsushima, Takayoshi Suzuki, Satoshi Kano, Takatsugu Mizumachi, Takashi Mori, Kentaro Nishioka, Motoyasu Shido, Norio Katoh, Hiroshi Taguchi, Noriyuki Fujima, Rikiya Onimaru, Isao Yokota, Keiji Kobashi, Shinichi Shimizu, Akihiro Homma, Hiroki Shirato, Hidefumi Aoyama

  Journal of radiation research 62 2 329 - 337 2021年03月10日 [査読有り]
   

  Pharyngeal cancer patients treated with intensity-modulated proton therapy (IMPT) using a model-based approach were retrospectively reviewed, and acute toxicities were analyzed. From June 2016 to March 2019, 15 pharyngeal (7 naso-, 5 oro- and 3 hypo-pharyngeal) cancer patients received IMPT with robust optimization. Simulation plans for IMPT and intensity-modulated X-ray therapy (IMXT) were generated before treatment. We also reviewed 127 pharyngeal cancer patients with IMXT in the same treatment period. In the simulation planning comparison, all of the normal-tissue complication probability values for dysphagia, dysgeusia, tube-feeding dependence and xerostomia were lower for IMPT than for IMXT in the 15 patients. After completing IMPT, 13 patients completed the evaluation, and 12 of these patients had a complete response. The proportions of patients who experienced grade 2 or worse acute toxicities in the IMPT and IMXT cohorts were 21.4 and 56.5% for dysphagia (P < 0.05), 46.7 and 76.3% for dysgeusia (P < 0.05), 73.3 and 62.8% for xerostomia (P = 0.43), 73.3 and 90.6% for mucositis (P = 0.08) and 66.7 and 76.4% for dermatitis (P = 0.42), respectively. Multivariate analysis revealed that IMPT was independently associated with a lower rate of grade 2 or worse dysphagia and dysgeusia. After propensity score matching, 12 pairs of IMPT and IMXT patients were selected. Dysphagia was also statistically lower in IMPT than in IMXT (P < 0.05). IMPT using a model-based approach may have clinical benefits for acute dysphagia.
• 尿量の経日変化および前立腺体積が放射線治療時の前立腺の位置に与える影響(The Impact of Daily Urinary Volume Variations and Prostate Volume on Prostate Position During Radiotherapy)

  Nishioka Kentaro, Hashimoto Takayuki, Yokota Isao, Katoh Norio, Kinoshita Rumiko, Yasuda Koichi, Takao Seishin, Yoshimura Takaaki, Aoyama Hidefumi, Shimizu Shinichi

  日本医学放射線学会学術集会抄録集 80回 S193 - S194 2021年03月
• The Impact of Daily Urinary Volume Variations and Prostate Volume on Prostate Position During Radiotherapy(和訳中)

  Nishioka Kentaro, Hashimoto Takayuki, Yokota Isao, Katoh Norio, Kinoshita Rumiko, Yasuda Koichi, Takao Seishin, Yoshimura Takaaki, Aoyama Hidefumi, Shimizu Shinichi

  日本医学放射線学会学術集会抄録集 80回 S193 - S194 2021年03月
• Pre-Treatment Apparent Diffusion Coefficient Histogram Metrics as a Predictor of Local Tumor Control After Proton Beam Therapy in Patients With Hepatocellular Carcinomas

  Kentaro Nishioka

  International Journal of Radiation Oncology Biology Physics 2021年
• Influence of Sub-Lethal Damage Repair On Biological Effectiveness of Proton with the Consideration of Dose Delivery Time Structure in Scanning Proton Therapy

  Kentaro Nishioka

  Medical Physics 2021年
• Are simple verbal instructions sufficient to ensure that bladder volume does not deteriorate prostate position reproducibility during spot scanning proton therapy?

  Kentaro Nishioka, Kento Gotoh, Takayuki Hashimoto, Takashige Abe, Takahiro Osawa, Ryuji Matsumoto, Isao Yokota, Norio Katoh, Rumiko Kinoshita, Koichi Yasuda, Toshiaki Yakabe, Takaaki Yoshimura, Seishin Takao, Nobuo Shinohara, Hidefumi Aoyama, Shinichi Shimizu, Hiroki Shirato

  BJR|Open 3 1 20210064 - 20210064 2021年01月 [査読有り]
   

  The purpose of this study is to investigate whether verbal instructions are sufficient for bladder volume (BV) control not to deteriorate prostate position reproducibility in image-guided spot scanning proton therapy (SSPT) for localized prostate cancer. A total of 268 treatment sessions in 12 consecutive prostate cancer patients who were treated with image-guided SSPT with fiducial markers were retrospectively analyzed. In addition to strict rectal volume control procedures, simple verbal instructions to void urine one hour before the treatment were used here. The BV was measured by a Bladder Scan just before the treatment, and the prostate motion was measured by intraprostatic fiducial markers and two sets of X-ray fluoroscopy images. The correlation between the BV change and prostate motion was assessed by linear mixed-effects models and systematic and random errors according to the reproducibility of the BV. The mean absolute BV change during treatment was from −98.7 to 86.3 ml (median 7.1 ml). The mean absolute prostate motion of the patients in the left-right direction was −1.46 to 1.85 mm; in the cranial-caudal direction it was −6.10 to 3.65 mm, and in the anteroposterior direction −1.90 to 5.23 mm. There was no significant relationship between the BV change and prostate motion during SSPT. The early and late genitourinary and gastrointestinal toxicity was minimal with a minimum follow up of 4.57 years. Simple verbal instructions about urination was suggested to be sufficient to control the BV not to impact on the prostate motion and clinical outcomes in image-guided SSPT. Careful attention to BV change is still needed when the seminal vesicle is to be treated. Our data demonstrated that there was no apparent relationship between BV changes and prostate position reproducibility and simple verbal instruction about urination could be sufficient for image-guided SSPT.
• Quantitative analysis of treatments using real-time image gated spot-scanning with synchrotron-based proton beam therapy system log data.

  Takaaki Yoshimura, Shinichi Shimizu, Takayuki Hashimoto, Kentaro Nishioka, Norio Katoh, Hiroshi Taguchi, Koichi Yasuda, Taeko Matsuura, Seishin Takao, Masaya Tamura, Sodai Tanaka, Yoichi M Ito, Yuto Matsuo, Hiroshi Tamura, Kenji Horita, Kikuo Umegaki, Hiroki Shirato

  Journal of applied clinical medical physics 21 12 10 - 19 2020年12月 [査読有り]
   

  A synchrotron-based real-time image gated spot-scanning proton beam therapy (RGPT) system with inserted fiducial markers can irradiate a moving tumor with high accuracy. As gated treatments increase the beam delivery time, this study aimed to investigate the frequency of intra-field adjustments corresponding to the baseline shift or drift and the beam delivery efficiency of a synchrotron-based RGPT system. Data from 118 patients corresponding to 127 treatment plans and 2810 sessions between October 2016 and March 2019 were collected. We quantitatively analyzed the proton beam delivery time, the difference between the ideal beam delivery time based on a simulated synchrotron magnetic excitation pattern and the actual treatment beam delivery time, frequency corresponding to the baseline shift or drift, and the gating efficiency of the synchrotron-based RGPT system according to the proton beam delivery machine log data. The mean actual beam delivery time was 7.1 min, and the simulated beam delivery time in an ideal environment with the same treatment plan was 2.9 min. The average difference between the actual and simulated beam delivery time per session was 4.3 min. The average frequency of intra-field adjustments corresponding to baseline shift or drift and beam delivery efficiency were 21.7% and 61.8%, respectively. Based on our clinical experience with a synchrotron-based RGPT system, we determined the frequency corresponding to baseline shift or drift and the beam delivery efficiency using the beam delivery machine log data. To maintain treatment accuracy within ± 2.0 mm, intra-field adjustments corresponding to baseline shift or drift were required in approximately 20% of cases. Further improvements in beam delivery efficiency may be realized by shortening the beam delivery time.
• Automatic Bladder Delineation on MR Images Using a Convolution Neural Network for Online Image-Guided Radiotherapy

  K. Nishioka, Y. Nomura, T. Hashimoto, R. Kinoshita, N. Katoh, H. Taguchi, K. Yasuda, T. Mori, Y. Uchinami, M. Otsuka, T. Matsuura, S. Takao, R. Suzuki, S. Tanaka, T. Yoshimura, H. Aoyama, S. Shimizu

  International Journal of Radiation Oncology*Biology*Physics 108 3 e288 - e289 2020年11月 [査読有り]
  
• 画像誘導治療の今後について 画像誘導陽子線治療の将来展望

  田口 大志, 橋本 孝之, 加藤 徳雄, 木下 留美子, 安田 耕一, 西岡 健太郎, 森 崇, 打浪 雄介, 宮本 直樹, 高尾 聖心, 清水 伸一, 青山 英史

  日本癌治療学会学術集会抄録集 58回 SY14 - 3 2020年10月
• The updated outcomes of bladder-preserving trimodal therapy using a real-time tumor-tracking radiotherapy system for patients with muscle-invasive bladder cancer.

  Haruka Miyata, Takahiro Osawa, Takashige Abe, Hiroshi Kikuchi, Ryuji Matsumoto, Satoru Maruyama, Kentaro Nishioka, Shinichi Shimizu, Takayuki Hashimoto, Hiroki Shirato, Nobuo Shinohara

  Japanese journal of clinical oncology 50 5 609 - 616 2020年01月19日 [査読有り][通常論文]
   

  OBJECTIVE: Bladder-preserving trimodal therapy is recognized as a promising alternative treatment for muscle-invasive bladder cancer. We report the updated outcomes of muscle-invasive bladder cancer patients that were treated using our treatment protocol, which involves radiotherapy delivered with a real-time tumor-tracking radiotherapy system. METHODS: Thirty-eight patients who were diagnosed with T2-T4N0M0 bladder cancer between 1998 and 2016 and had clinically inoperable disease or refused to undergo surgery were enrolled. The treatment protocol included maximal transurethral resection followed by whole-bladder radiotherapy (40 Gy). Concurrent nedaplatin-based chemotherapy was administered to patients with adequate renal function. At the time of the first evaluation (via transurethral resection of the tumor bed), fiducial markers were endoscopically inserted into the bladder wall around the tumor. A boost of 25 Gy was administered using the real-time tumor-tracking radiotherapy system. The second evaluation (via transurethral resection of the tumor bed) was performed 6 months after the start of treatment. The Kaplan-Meier method and Cox hazards analysis were used to analyze overall survival and cancer-specific survival. RESULTS: The median duration of the follow-up period was 28 months (range: 3-161 months). The 5- and 10-year overall survival rates were 54.9 and 41.2%, respectively. Twenty-five (65.8%) and twenty (74.1%) patients had achieved complete responses to chemoradiation at the first and second evaluations, respectively. In univariate and multivariate analyses, performance status was found to be significantly associated with overall survival [P = 0.03, hazard ratio: 3.48, 95% confidence interval: 1.15-10.6] and cancer-specific survival [P = 0.02, hazard ratio: 4.57, 95% confidence interval: 1.32-16.9], and sex was shown to be significantly associated with cancer-specific survival [P = 0.03, hazard ratio: 3.07, 95% confidence interval: 1.09-8.30]. CONCLUSIONS: Our bladder-preserving trimodal therapy protocol, which involves the use of a real-time tumor-tracking radiotherapy system, produced an acceptable overall survival rate. This therapy is a reasonable alternative for patients that are medically unfit for or do not want to undergo cystectomy.
• The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy.

  Yasuhiro Dekura, Kentaro Nishioka, Takayuki Hashimoto, Naoki Miyamoto, Ryusuke Suzuki, Takaaki Yoshimura, Ryuji Matsumoto, Takahiro Osawa, Takashige Abe, Yoichi M Ito, Nobuo Shinohara, Hiroki Shirato, Shinichi Shimizu

  Radiation oncology (London, England) 14 1 226 - 226 2019年12月12日 [査読有り][通常論文]
   

  PURPOSE: To determine the best method to contour the planning organ at risk volume (PRV) for the urethra, this study aimed to investigate the displacement of a Foley catheter in the urethra with a soft and thin guide-wire. METHODS: For each patient, the study used two sets of computed tomography (CT) images for radiation treatment planning (RT-CT): (1) set with a Foley urethral catheter (4.0 mm diameter) plus a guide-wire (0.46 mm diameter) in the first RT-CT and (2) set with a guide-wire alone in the second CT recorded 2 min after the first RT-CT. Using three fiducial markers in the prostate for image fusion, the displacement between the catheter and the guide-wire in the prostatic urethra was calculated. In 155 consecutive patients treated between 2011 and 2017, 5531 slices of RT-CT were evaluated. RESULTS: Assuming that ≥3.0 mm of difference between the catheter and the guide-wire position was a significant displacement, the urethra with the catheter was displaced significantly from the urethra with the guide-wire alone in > 20% of the RT-CT slices in 23.2% (36/155) of the patients. The number of patients who showed ≥3.0 mm anterior displacement with the catheter in ≥20% RT-CT slices was significantly larger at the superior segment (38/155) than at the middle (14/155) and inferior segments (18/155) of the prostatic urethra (p < 0.0167). CONCLUSIONS: The urethral position with a Foley catheter is different from the urethral position with a thin and soft guide-wire in a significant proportion of the patients. This should be taken into account for the PRV of the urethra to ensure precise radiotherapy such as in urethra-sparing radiotherapy.
• Analysis of treatment process time for real-time-image gated-spot-scanning proton-beam therapy (RGPT) system.

  Yoshimura T, Shimizu S, Hashimoto T, Nishioka K, Katoh N, Inoue T, Taguchi H, Yasuda K, Matsuura T, Takao S, Tamura M, Ito YM, Matsuo Y, Tamura H, Horita K, Umegaki K, Shirato H

  Journal of applied clinical medical physics 21 2 38 - 49 2019年12月 [査読有り][通常論文]
   

  We developed a synchrotron-based real-time-image gated-spot-scanning proton-beam therapy (RGPT) system and utilized it to clinically operate on moving tumors in the liver, pancreas, lung, and prostate. When the spot-scanning technique is linked to gating, the beam delivery time with gating can increase, compared to that without gating. We aim to clarify whether the total treatment process can be performed within approximately 30 min (the general time per session in several proton therapy facilities), even for gated-spot-scanning proton-beam delivery with implanted fiducial markers. Data from 152 patients, corresponding to 201 treatment plans and 3577 sessions executed from October 2016 to June 2018, were included in this study. To estimate the treatment process time, we utilized data from proton beam delivery logs during the treatment for each patient. We retrieved data, such as the disease site, total target volume, field size at the isocenter, and the number of layers and spots for each field, from the treatment plans. We quantitatively analyzed the treatment process, which includes the patient load (or setup), bone matching, marker matching, beam delivery, patient unload, and equipment setup, using the data obtained from the log data. Among all the cases, 90 patients used the RGPT system (liver: n = 34; pancreas: n = 5; lung: n = 4; and prostate: n = 47). The mean and standard deviation (SD) of the total treatment process time for the RGPT system was 30.3 ± 7.4 min, while it was 25.9 ± 7.5 min for those without gating treatment, excluding craniospinal irradiation (CSI; head and neck: n = 16, pediatric: n = 31, others: n = 15); for CSI (n = 11) with two or three isocenters, the process time was 59.9 ± 13.9 min. Our results demonstrate that spot-scanning proton therapy with a gating function can be achieved in approximately 30-min time slots.
• 高リスク前立腺癌に対するロボット支援前立腺全摘除術と放射線療法の臨床的比較検討

  松本 隆児, 古御堂 純, 宮田 遥, 菊地 央, 大澤 崇宏, 安部 崇重, 西岡 健太郎, 橋本 孝之, 清水 伸一, 篠原 信雄

  日本泌尿器内視鏡学会総会 33回 P - 1 (一社)日本泌尿器内視鏡・ロボティクス学会 2019年11月
• 高リスク前立腺癌に対するロボット支援前立腺全摘除術と放射線療法の臨床的比較検討

  松本 隆児, 古御堂 純, 宮田 遥, 菊地 央, 大澤 崇宏, 安部 崇重, 西岡 健太郎, 橋本 孝之, 清水 伸一, 篠原 信雄

  日本泌尿器内視鏡学会総会 33回 P - 1 (一社)日本泌尿器内視鏡・ロボティクス学会 2019年11月
• Analysis of Beam Delivery Times and Dose Rates for the Treatment of Mobile Tumors Using Real Time Image Gated Spot-Scanning Proton Beam Therapy

  S. Shimizu, T. Yoshimura, N. Katoh, T. Inoue, T. Hashimoto, K. Nishioka, S. Takao, T. Matsuura, N. Miyamoto, Y.M. Ito, K. Umegaki, H. Shirato

  International Journal of Radiation Oncology*Biology*Physics 102 3 S182 - S183 2018年11月 [査読有り]
  
• Real-Time Tumor-Tracking Radiotherapy and General Stereotactic Body Radiotherapy for Adrenal Metastasis in Patients With Oligometastasis

  Katoh N, Onishi H, Uchinami Y, Inoue T, Kuriyama K, Nishioka K, Shimizu S, Komiyama T, Miyamoto N, Shirato H

  TECHNOLOGY IN CANCER RESEARCH & TREATMENT 17 1533033818809983 - 1533033818809983 2018年11月 [査読有り][通常論文]
   

  BACKGROUND: Precise local radiotherapy for adrenal metastasis can prolong the useful life of patients with oligometastasis. The aim of this retrospective, 2-center study was to establish the safety and effectiveness of real-time tumor-tracking radiotherapy and general stereotactic body radiotherapy in treating patients with adrenal metastatic tumors. MATERIALS AND METHODS: Thirteen lesions in 12 patients were treated with real-time tumor-tracking radiotherapy (48 Gy in 8 fractions over 2 weeks) and 8 lesions in 8 patients were treated with general stereotactic body radiotherapy (40-50 Gy in 5-8 fractions over 2 weeks or 60-70 Gy in 10 fractions over 2 weeks). Overall survival rates, local control rates, and adverse effects were analyzed. RESULTS: The actuarial overall survival rates for all patients at 1 and 2 years were 78.5% and 45.8%, respectively, with a median follow-up of 17.5 months, and the actuarial local control rates for all tumors at 1 and 2 years were 91.7% and 53.0%, respectively, with a median follow-up of 9 months. A complete local tumor response was obtained in 3 tumors treated by real-time tumor-tracking radiotherapy (lung adenocarcinomas with diameters of 35, 40, and 60 mm). There was a statistically significant difference in the local control between the groups treated by real-time tumor-tracking radiotherapy (100% at 1 year) and general stereotactic body radiotherapy (50% at 1 year; P < .001). No late adverse reactions at Grade 2 or higher were reported for either treatment group. CONCLUSIONS: This study showed that although both treatments are safe and effective, the real-time tumor-tracking radiotherapy is more effective than general stereotactic body radiotherapy in local control for adrenal metastasis.
• Determination of the urethra position for accurate radiation therapy of prostate cancers

  Dekura Yasuhiro, Nishioka Kentaro, Hashimoto Takayuki, Miyamoto Naoki, Suzuki Ryusuke, Matsumoto Ryuji, Osawa Takahiro, Abe Takashige, Maruyama Satoru, Shinohara Nobuo, Shirato Hiroki, Shimizu Shinichi

  INTERNATIONAL JOURNAL OF UROLOGY 25 445 - 445 2018年10月 [査読有り][通常論文]
  
• Long-term Outcomes of Tri-modality Therapy using a real-time tumor-tracking radiotherapy system for Patients with Muscle-invasive Bladder Cancer

  Kentaro Nishioka

  International Journal of Urology 25 321  2018年10月 [査読有り][通常論文]
  
• Prospective study to evaluate the safety of the world-first spot-scanning dedicated, small 360-degree gantry, synchrotron-based proton beam therapy system

  Kentaro Nishioka, Anussara Prayongrat, Kota Ono, Shunsuke Onodera, Takayuki Hashimoto, Norio Katoh, Tetsuya Inoue, Rumiko Kinoshita, Koichi Yasuda, Takashi Mori, Rikiya Onimaru, Hiroki Shirato, Shinichi Shimizu

  Journal of Radiation Research 59 suppl_1 i63 - i71 2018年03月01日 [査読有り][招待有り]
   

  © The Author(s) 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology. This is a report of a single-institution prospective study evaluating the safety of a spot-scanning dedicated, small 360-degree gantry, synchrotron-based proton beam therapy (PBT) system. Data collection was performed for 56 patients with 59 treatment sites who received proton beam therapy at Hokkaido University Hospital between March 2014 and July 2015. Forty-one patients were male and 15 were female. The median age was 66 years. The primary lesion sites were prostate (n = 17), bone/soft tissue (n = 10), liver (n = 7), lung (n = 6), central nervous system (n = 5), colon (n = 2), pancreas (n = 2), kidney (n = 2) and others (n = 5). Chemotherapy was administered in 11 patients. The prescribed total dose was from 20 to 76 GyE (Radiobiological equivalent dose, RBE = 1.1), with the median dose of 65 GyE in 4 to 35 fractions. No PBT-related Common Terminology Criteria for Adverse Events Grade 4 or 5 toxicities were observed; the incidence of early PBT-related Grade 4 adverse events was 0% (95% confidence interval 0 to 6.38%). The most common Grade 3 toxicities were hematologic toxicity (12.5%) unlikely to be related to the PBT. One patient developed a left femoral neck fracture (Grade 3) at 14.5 months after PBT for chondrosarcoma of the left pelvis. The pathological findings showed no other malignancies, suggesting that it was possibly related to the PBT. In conclusion, the spot-scanning dedicated, synchrotron-based PBT system is feasible, but further studies on its long-term safety and efficacy are warranted.
• A Study On the Influence of Changing the Motion Recognition Rate On the Dose Accuracy of Spot-Scanning Proton Therapy

  Kentaro Nishioka

  Medical Physics 2018年
• A simulation study on the dosimetric benefit of real-time motion compensation in spot-scanning proton therapy for prostate

  Yusuke Fujii, Taeko Matsuura, Seishin Takao, Yuka Matsuzaki, Takaaki Fujii, Naoki Miyamoto, Kikuo Umegaki, Kentaro Nishioka, Shinichi Shimizu, Hiroki Shirato

  JOURNAL OF RADIATION RESEARCH 58 4 591 - 597 2017年07月 [査読無し][通常論文]
   

  For proton spot scanning, use of a real-time-image gating technique incorporating an implanted marker and dual fluoroscopy facilitates mitigation of the dose distribution deterioration caused by interplay effects. This study explored the advantages of using a real-time-image gating technique, with a focus on prostate cancer. Two patient-positioning methods using fiducial markers were compared: (i) patient positioning only before beam delivery, and (ii) patient positioning both before and during beam delivery using a real-time-gating technique. For each scenario, dose distributions were simulated using the CT images of nine prostate cancer patients. Treatment plans were generated using a single-field proton beam with 3-mm and 6-mm lateral margins. During beam delivery, the prostate was assumed to move by 5 mm in four directions that were perpendicular to the beam direction at one of three separate timings (i.e. after the completion of the first, second and third quartiles of the total delivery of spot irradiation). Using a 3-mm margin and second quartile motion timing, the averaged values for Delta D-99, Delta D-95, Delta D-5 and D5-95 were 5.1%, 3.3%, 3.6% and 9.0%, respectively, for Scenario (i) and 2.1%, 1.5%, 0.5% and 4.1%, respectively, for Scenario (ii). The margin expansion from 3 mm to 6 mm reduced the size of Delta D-99, Delta D-95, Delta D-5 and D5-95 only with Scenario (i). These results indicate that patient positioning during beam delivery is an effective way to obtain better target coverage and uniformity while reducing the target margin when the prostate moves during irradiation.
• Analysis of inter- and intra fractional partial bladder wall movement using implanted fiducial markers

  Kentaro Nishioka, Shinichi Shimizu, Nobuo Shinohara, Yoichi M. Ito, Takashige Abe, Satoru Maruyama, Norio Katoh, Rumiko Kinoshita, Takayuki Hashimoto, Naoki Miyamoto, Rikiya Onimaru, Hiroki Shirato

  RADIATION ONCOLOGY 12 1 44 - 44 2017年03月 [査読有り][通常論文]
   

  Background: Current adaptive and dose escalating radiotherapy for muscle invasive bladder cancer requires knowledge of both inter-fractional and intra-fractional motion of the bladder wall involved. The purpose of this study is to characterize inter-and intra-fractional movement of the partial bladder wall using implanted fiducial markers and a real-time tumor-tracking radiotherapy system. Methods: Two hundred fifty one sessions with 29 patients were analysed. After maximal transurethral bladder tumor resection and 40 Gy of whole bladder irradiation, up to six gold markers were implanted transurethrally into the bladder wall around the tumor bed and used for positional registration. We compared the systematic and random uncertainty of positions between cranial vs. caudal, left vs. right, and anterior vs. posterior tumor groups. The variance in intrafractional movement and the percentage of sessions where 3 mm and 5 mm or more of intrafractional wall movement occurring at 2, 4, 6, 8, 10, and at more than 10 min until the end of a session were determined. Results: The cranial and anterior tumor group showed larger interfractional uncertainties in the position than the opposite side tumor group in the CC and AP directions respectively, but these differences did not reach significance. Among the intrafractional uncertainty of position, the cranial and anterior tumor group showed significantly larger systematic uncertainty of position than the groups on the opposite side in the CC direction. The variance of intrafractional movement increased over time; the percentage of sessions where intrafractional wall movement was larger than 3 mm within 2 min of the start of a radiation session or larger than 5 mm within 10 min was less than 5%, but this percentage was increasing further during the session, especially in the cranial and anterior tumor group. Conclusions: More attention for intrafractional uncertainty of position is required in the treatment of cranial and anterior bladder tumors especially in the CC direction. The optimal internal margins in each direction should be chosen or a precise intrafractional target localization system is required depending on the tumor location and treatment delivery time in the setting of partial bladder radiotherapy.
• 乳房温存術後接線照射後にFitz‐Hugh‐Curtis症候群様の肝周囲炎を来した1例

  出倉康裕, 森崇, 西川由記子, 木下留美子, 橋本孝之, 白土博樹, 西岡健太郎, 清水伸一, 細田充主, 山下啓子

  Japanese Journal of Radiology 35 Supplement 4 - 4 (公社)日本医学放射線学会 2017年02月25日 [査読無し][通常論文]
  
• 前立腺癌の放射線治療時における尿量の変動の解析

  後藤謙斗, 西岡健太郎, 松崎有華, 松浦妙子, 高尾聖心, 橋本孝之, 木下留美子, 西川由記子, 清水伸一, 白土博樹

  日本放射線腫瘍学会高精度放射線外部照射部会学術大会プログラム・抄録集 30th 55  2017年 [査読無し][通常論文]
  
• Analysis of Durations and Dose Rates for Treatment of Moving Liver Tumors Using Real-Time Image Gated Spot Scanning Proton Beam Therapy

  S. Shimizu, N. Katoh, T. Hashimoto, K. Nishioka, T. Yoshimura, S. Takao, T. Matsuura, N. Miyamoto, K. Umegaki, H. Shirato

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 96 2 S211 - S212 2016年10月 [査読無し][通常論文]
  
• Radiation Dose to Internal Mammary Lymph Node in Standard Tangential Breast Irradiation

  R. Kinoshita, S. Shimizu, Y. Nishikawa, K. Nishioka, T. Hashimoto, R. Suzuki, H. Shirato

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 96 2 E17 - E18 2016年10月 [査読無し][通常論文]
  
• 椎体IMRTとその精度に関する研究

  安田耕一, 清水伸一, 橋本孝之, SUTHERLAND Ken, 白土博樹, 土屋和彦, 加藤徳雄, 鬼丸力也, 木下留美子, 井上哲也, 西岡健太郎, 西川由記子, 森崇, 原田慶一, 原田八重, 鈴木隆介, 寅松千枝, 松浦妙子, 高尾聖心, 宮本直樹, 伊藤陽一

  Japanese Journal of Radiology 34 Supplement 5 - 5 (公社)日本医学放射線学会 2016年02月25日 [査読無し][通常論文]
  
• Development of a Real-Time Image Gated Proton Beam Therapy (RGPT) System and Its Initial Clinical Application to Respiratory Moving Liver Tumors

  S. Shimizu, N. Katoh, S. Takao, T. Matsuura, N. Miyamoto, T. Hashimoto, K. Nishioka, T. Yoshimura, Y. Matsuzaki, R. Kinoshita, Y. Nishikawa, R. Onimaru, K. Umegaki, H. Shirato

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 93 3 S42 - S42 2015年11月 [査読無し][通常論文]
  
• 内分泌療法併用動態追跡放射線治療の治療成績

  丸山 覚, 篠原 信雄, 安部 崇重, 土屋 邦彦, 宮島 直人, 西岡 健太郎, 清水 伸一, 白土 博樹, 野々村 克也

  泌尿器外科 27 8 1349 - 1351 医学図書出版(株) 2014年08月 [査読無し][通常論文]
   

  【目的】高リスク前立腺癌に対する内分泌療法を併用した動態追跡強度変調放射線治療(RT-IMRT)の治療成績を検討する。【対象と方法】RT-IMRTを施行した204例を対象とした。治療法毎に群分けし、治療成績を比較検討した。【結果】内分泌療法を併用したのは19例(併用群)、併用しなかったのが40例(非併用群)であった。5年時の疾患特異生存率/全生存率/生化学的非再発率はそれぞれ、併用群で100%/100%/95%、非併用群で100%/100%/59%であり併用群の予後が有意に良い結果であった。【結語】内分泌療法併用RT-IMRTは今後期待される治療法と思われた。(著者抄録)
• Early results of urethral dose reduction and small safety margin in intensity-modulated radiation therapy (IMRT) for localized prostate cancer using a real-time tumor-tracking radiotherapy (RTRT) system

  Shinichi Shimizu, Kentaro Nishioka, Ryusuke Suzuki, Nobuo Shinohara, Satoru Maruyama, Takashige Abe, Rumiko Kinoshita, Norio Katoh, Rikiya Onimaru, Hiroki Shirato

  Radiation Oncology 9 1 118 - 118 BioMed Central 2014年05月21日 [査読有り][通常論文]
   

  Background: We prospectively assessed the utility of intensity-modulated radiation therapy (IMRT) with urethral dose reduction and a small margin between the clinical target volume (CTV) and the planning target volume (PTV) for patients with localized prostate cancer.Methods: The study population was 110 patients in low- (14.5%), intermediate- (41.8%), and high-risk (43.6%) categories. Three gold fiducial markers were inserted into the prostate. A soft guide-wire was used to identify the urethra when computed tomography (CT) scan for treatment planning was performed. A dose constraint of V70 < 10% was applied to the urethral region. Margins between the CTV-PTV were set at 3 mm in all directions. Patients were treated with 70 Gy IMRT in 30 fractions (D95 of PTV) over 7.5 weeks. The patient couch was adjusted to keep the gold markers within 2.0 mm from their planned positions with the use of frequent on-line verification.Results: The median follow-up period was 31.3 (3.2 to 82.1) months. The biochemical relapse-free survival (bRFS) rates at 3 years were 100%, 93.8% and 89.5% for the low-, intermediate-, and high-risk patients, respectively. The incidences of acute adverse events (AEs) were 45.5% and 0.9% for grades 1 and 2, respectively. The late AEs were grade 1 cystitis in 10.0% of the patients, rectal bleeding in 7.3%, and urinary urgency in 6.4%. Only three patients (2.7%) developed grade 2 late AEs.Conclusions: On-line image guidance with precise correction of the table position during radiotherapy achieved one of the lowest AEs rates with a bRFS equal to the highest in the literature. © 2014 Shimizu et al.; licensee BioMed Central Ltd.
• 膀胱癌に対する画像誘導放射線治療に関する研究

  西岡健太郎

  北海道大学 2014年03月 [査読有り][通常論文]
  
• 放射線治療に関する名称付けルール

  安田耕一, 土屋和彦, 井上哲也, 西岡健太郎, 原田慶一, 西川由記子, 鬼丸力也, 清水伸一, 加藤徳雄, 木下留美子, 小野寺俊介, 白土博樹, 鈴木隆介, 藤田勝久, 辻真太郎, 山崎理衣

  Jpn J Radiol 32 Supplement 7 - 7 (公社)日本医学放射線学会 2014年02月25日 [査読無し][通常論文]
  
• 北海道大学病院における髄膜腫に対する強度変調放射線治療(IMRT)の初期成績

  西川由記子, 原田慶一, 西岡健太郎, 安田耕一, 井上哲也, 土屋和彦, 小野寺俊輔, 木下留美子, 加藤徳雄, 清水伸一, 鬼丸力也, 白土博樹, 鈴木隆介, 石川正純

  Jpn J Radiol 32 Supplement 5 - 5 (公社)日本医学放射線学会 2014年02月25日 [査読無し][通常論文]
  
• 前立腺癌に対する動体追跡放射線療法における金マーカー埋め込み術

  土屋 邦彦, 篠原 信雄, 丸山 覚, 清水 伸一, 西岡 健太郎, 安部 崇重, 白土 博樹, 野々村 克也

  泌尿器外科 27 2 263 - 263 医学図書出版(株) 2014年02月 [査読無し][通常論文]
  
• Dosimetric comparison between intensity-modulated radiotherapy and standard wedged tangential technique for whole-breast radiotherapy in Asian women with relatively small breast volumes

  Kazuhiko Tsuchiya, Rumiko Kinoshita, Shinichi Shimizu, Kentaro Nishioka, Keiichi Harada, Noboru Nishikawa, Ryusuke Suzuki, Hiroki Shirato

  Radiological Physics and Technology 7 1 67 - 72 2014年01月01日 [査読無し][通常論文]
   

  We sought to investigate whether intensity-modulated radiotherapy (IMRT) has a dosimetric advantage compared to the standard wedged tangential technique (SWT) for whole-breast radiotherapy (WBRT) in Asian women with relatively small breast volume. Computed tomography images of 25 Asian patients with early-stage breast cancer (right 15, left 10) used for WBRT planning were examined. After contouring the target volumes and bilateral lungs and, for left-side treatment, the heart, 4 plans were made for each patient: namely, SWT, tangential-field IMRT (T-IMRT), 3-field IMRT (3F-IMRT), and 4-field IMRT (4F-IMRT). The prescribed dose was 5000 cGy. The median planning target volume (PTV) for WBRT was 552.6 cc (range 288.8-1518.4 cc). Compared to SWT, (1) T-IMRT achieved significant improvement for dose homogeneity in the PTV (p < 0.001) and the dose received by 2 % (D2) of the PTV (p < 0.001). T-IMRT also reduced the bilateral lung mean dose (p < 0.001) and the ipsilateral lung volume which received more than 20 Gy (V20) (p = 0.01). (2) 3F-IMRT resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). (3) 4F-IMRT also resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). Tangential-field IMRT provided an improved dose distribution compared with SWT for WBRT in Asian women with a relatively small breast volume. © Japanese Society of Radiological Technology and Japan Society of Medical Physics 2013.
• Prospective phase II study of image-guided local boost using a real-time tumor-tracking radiotherapy (RTRT) system for locally advanced bladder cancer

  Nishioka K, Shimizu S, Shinohara N, Ito Y. M, Abe T, Maruyama S, Kinoshita R, Harada K, Nishikawa N, Miyamoto N, Onimaru R, Shirato H

  Jpn J Clin Oncol 44 1 28 - 35 2014年01月 [査読有り][通常論文]
   

  The real-time tumor-tracking radiotherapy system with fiducial markers has the advantage that it can be used to verify the localization of the markers during radiation delivery in real-time. We conducted a prospective Phase II study of image-guided local-boost radiotherapy for locally advanced bladder cancer using a real-time tumor-tracking radiotherapy system for positioning, and here we report the results regarding the safety and efficacy of the technique. Twenty patients with a T2-T4N0M0 urothelial carcinoma of the bladder who were clinically inoperable or refused surgery were enrolled. Transurethral tumor resection and 40 Gy irradiation to the whole bladder was followed by the transurethral endoscopic implantation of gold markers in the bladder wall around the primary tumor. A boost of 25 Gy in 10 fractions was made to the primary tumor while maintaining the displacement from the planned position at less than 2 mm during radiation delivery using a real-time tumor-tracking radiotherapy system. The toxicity, local control and survival were evaluated. Among the 20 patients, 14 were treated with concurrent chemoradiotherapy. The median follow-up period was 55.5 months. Urethral and bowel late toxicity (Grade 3) were each observed in one patient. The local-control rate, overall survival and cause-specific survival with the native bladder after 5 years were 64, 61 and 65. Image-guided local-boost radiotherapy using a real-time tumor-tracking radiotherapy system can be safely accomplished, and the clinical outcome is encouraging. A larger prospective multi-institutional study is warranted for more precise evaluations of the technological efficacy and patients quality of life.
• Longitudinal comparison of quality of life after real-time tumor-tracking intensity-modulated radiation therapy and radical prostatectomy in patients with localized prostate cancer.

  Shinohara N, Maruyama S, Shimizu S, Nishioka K, Abe T, C-Hatanaka K, Oba K, Nonomura K, Shirato H

  Journal of radiation research 54 6 1095 - 101 2013年11月01日 [査読有り][通常論文]
   

  The purpose of this study was to compare the quality of life (QOL) in patients with localized prostate cancer (PC) after intensity-modulated radiation therapy assisted with a fluoroscopic real-time intensity-modulated radiation therapy (RT-IMRT) tumor-tracking system versus the QOL after radical prostatectomy (RP). Between 2003 and 2006, 71 patients were enrolled in this longitudinal prospective study. Each patient was allowed to decide which treatment modality they would receive. Of the 71 patients, 23 patients underwent RT-IMRT, while 48 opted for RP. No patient received neo-adjuvant or adjuvant hormone therapy. The global QOL and disease-specific-QOL were evaluated before treatment and again at 1, 3 and 5 years after treatment. There was no significant difference in the background characteristics between the two groups. The 5-year biochemical progression-free survival was 90% in the RT-IMRT and 79% in the RP group. In the RT-IMRT group, there was no significant deterioration of the global QOL or disease-specific QOL through 5 years post-treatment. In the RP group, the urinary function, sexual function, and sexual bother indicators significantly deteriorated after treatment. Urinary and sexual function was significantly better in the RT-IMRT group at 1, 3 and 5 years post-treatment compared to the RP group. RT-IMRT may be a preferable treatment for localized PC because of similar efficacy to RP but better post-treatment QOL.
• 悪性腫瘍の骨転移病巣に対する局所外部放射線照射に伴う骨髄抑制の影響

  西山 典明, 鈴木 恵士郎, 藤野 賢治, 西岡 健太郎, 沖本 智昭, 西尾 正道

  Radioisotopes 62 9 623 - 630 Japan Radioisotope Association 2013年09月15日 

  骨転移病巣への局所外部放射線照射を行った49例を対象に骨髄機能への影響を検討した。血小板は暫減し，照射前値に対する百分率の平均は終了後12週間で88.0％であった。リンパ球は照射開始後2週間で74.3％へ低下したが，照射終了12週間で照射前値に復した。リンパ球低下率と照射面積及び照射前リンパ球数との間に弱い負の相関がみられた。他の血球を含め問題となる検査値の悪化はなく，局所外照射により重篤又は長期の骨髄抑制は生じないと考えられた。
• Evaluation of inter-observer variability of bladder boundary delineation on cone-beam CT

  Kentaro Nishioka, Shinichi Shimizu, Rumiko Kinoshita, Tetsuya Inoue, Shunsuke Onodera, Koichi Yasuda, Keiichi Harada, Yukiko Nishikawa, Rikiya Onimaru, Hiroki Shirato

  RADIATION ONCOLOGY 8 185 185 - 185 2013年07月 [査読有り][通常論文]
   

  Background: In-room cone-beam computerized tomography (CBCT) imaging is a promising method to reduce setup errors, especially in organs such as the bladder that often have large intrafractional variations due to organ movement. CBCT image quality is limited by low contrast and imaging artifacts, but few data have been reported about inter-observer variability of bladder boundary delineation on CBCT. The aim of this work was to analyze and evaluate the inter-observer contouring uncertainties of bladder boundary delineation on CBCT images in a prospective fashion. Methods: Five radiation oncologists contoured 10 bladders using the CBCT datasets of consecutive 10 patients (including 4 females) who were irradiated to the pelvic region. Prostates were also contoured in male patients. Patients who had had prostatectomy were excluded. The coefficient of variation (COV), conformity index (CIgen), and coordinates of center-of-mass (COM) of the bladder and prostate were calculated for each patient. Results: The mean COV for the bladder and prostate was 0.08 and 0.20, respectively. The mean CIgen of the bladder and prostate was 0.81 and 0.66, respectively. The root mean square (RMS) of the inter-observer standard deviation (s) of the COM displacement in the left-right (LR) and anterior-posterior (AP) direction was 0.79, 0.87 and 0.54 for the bladder and 0.63, 0.99 and 1.72 for the prostate. Regarding the mean COV and CIgen for the bladder, the differences between males and females were not significant. Conclusions: Inter-observer variability for bladder delineation on CBCT images was substantially small regardless of gender. We believe that our results support the applicability of CBCT in adaptive radiotherapy for bladder cancer.
• 前立腺癌に対する動体追跡放射線療法における金マーカー埋め込み術

  土屋邦彦, 篠原信雄, 丸山覚, 清水伸一, 西岡健太郎, 安部崇重, 白土博樹, 野々村克也

  日本泌尿器科学会雑誌 104 2 288 - 288 (一社)日本泌尿器科学会 2013年03月20日 [査読無し][通常論文]
  
• 動体追跡装置を用いた位置照合に基づく膀胱癌放射線治療時のマージンの解析

  西岡健太郎, 清水伸一, 安部崇重, 丸山覚, 鬼丸力也, 木下留美子, 小野寺俊輔, 原田慶一, 篠原信雄, 白土博樹

  日本医学放射線学会総会抄録集 72nd S397 - S397 (公社)日本医学放射線学会 2013年02月28日 [査読無し][通常論文]
  
• 子宮頚癌術後全骨盤照射のためのRapidArcと固定多門IMRT間の線量比較研究

  土屋和彦, 原田慶一, 西岡健太郎, 木下留美子, 清水伸一, 白土博樹

  Jpn J Radiol 31 Supplement 1 11  2013年02月25日 [査読無し][通常論文]
  
• Safety, Stability, and Location of Implantation of Multiple Gold Markers Into the Soft Bladder Wall by Rigid Cystoscopy

  Nishioka K, Shimizu S, Onimaru R, Kinoshita R, Kato N, Harada K, Abe T, Maruyama S, Shinohara N, Shirato H

  International Journal of Radiation Oncology Biology Physics 87 2 S397  2013年 [査読有り][通常論文]
  
• Decreasing Acute and Late Toxicity Using Urethral Dose Reduction and Smaller Safety Margin Around CTV for Prostate Cancer Intensity Modulated Radiation Therapy (IMRT) With a Real-time Tumor-tracking (RTRT) System

  S. Shimizu, K. Nishioka, R. Onimaru, R. Kinoshita, K. Harada, N. Nishikawa, T. Abe, S. Maruyama, N. Shinohara, H. Shirato

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 84 3 S181 - S181 2012年11月 [査読無し][通常論文]
  
• リンフォーマの画像診断と新規治療のプラクティス 皮膚悪性リンパ腫に対する放射線治療

  鬼丸 力也, 清水 伸一, 土屋 和彦, 加藤 徳雄, 木下 留美子, 井上 哲也, 小野寺 俊輔, 安田 耕一, 西岡 健太郎, 白土 博樹

  日本皮膚悪性腫瘍学会学術大会プログラム・抄録集 28回 82 - 82 日本皮膚悪性腫瘍学会 2012年06月 [査読無し][通常論文]
  
• 北海道大学病院における乳房外Paget病の放射線治療経験

  原田慶一, 木下留美子, 加藤徳雄, 西岡健太郎, 清水伸一, 鬼丸力也, 白土博樹

  日本医学放射線学会総会抄録集 71st S375  2012年02月29日 [査読無し][通常論文]
  
• 北海道大学病院における乳房温存療法の治療成績

  木下留美子, 清水伸一, 西岡健太郎, 原田慶一, 小野寺俊輔, 田口大志, 細田充主, 田口和典, 高橋弘昌, 白土博樹

  日本医学放射線学会総会抄録集 71st S318  2012年02月29日 [査読無し][通常論文]
  
• Interfractional Setup Error and Intrafractional Bladder Motion During Radiation Therapy for Bladder Tumors

  Nishioka K, Shimizu S, Onimaru R, Kinoshita R, Harada K, Nishikawa N, Abe T, Maruyama S, Shinohara N, Shirato H

  International Journal of Radiation Oncology Biology Physics 84 3 S769  2012年 [査読有り][通常論文]
  
• 画像誘導局所Boostを併用した局所進行膀胱癌に対する根治的放射線治療

  西岡健太郎, 清水伸一, 大坂康博, 西川昇, 喜多村圭, 白土博樹, 篠原信雄, 佐澤陽

  日本医学放射線学会総会抄録集 70th S219-S220  2011年02月28日 [査読無し][通常論文]
  
• Organ-conserving Definitive Radiotherapy For Locally Advanced Bladder Carcinoma With Image-guided Local Boost

  Kentaro Nishioka

  International Journal of Radiation Oncology Biology Physics 81 2 S449  2011年 [査読有り][通常論文]
  
• Use of implanted markers and interportal adjustment with real-time tracking radiotherapy system to reduce intrafraction prostate motion.

  SHIMIZU Shinichi, OSAKA Yasuhiro, NISHIOKA Kentaro, ONIMARU Rikiya, SHIRATO Hiroki, SHINOHARA Nobuo, SAZAWA Ataru, SUZUKI Ryusuke

  Int J Radiat Oncol Biol Phys 81 4 E393 - E399 2011年 [査読有り][通常論文]
   

  PURPOSE: Interportal adjustment was applied to patients with prostate cancer using three fiducial markers and two sets of fluoroscopy in a real-time tumor-tracking radiotherapy (RTRT) system. The incidence of table position adjustment required to keep intrafractional uncertainty within 2.0 mm was investigated in this study. METHODS AND MATERIALS: The coordinates of the center of gravity of the three fiducial markers were measured at the start of every portal irradiation in intensity-modulated radiotherapy (IMRT) with seven ports. The table position was adjusted to the planned position if the discrepancy was larger than 2.0 mm in the anterior-posterior (AP), cranial-caudal (CC), or left-right (LR) directions. In total, we analyzed 4,541 observations in 20 patients who received 70 Gy in 30 fractions (7.6 times a day on average). RESULTS: The incidence of table position adjustment at 10 minutes from the initial setup of each treatment was 14.2%, 12.3%, and 5.0% of the observations in the AP, CC, and LR directions, respectively. The accumulated incidence of the table position adjustment was significantly higher at 10 minutes than at 2 minutes for AP (p = 0.0033) and CC (p = 0.0110) but not LR (p = 0.4296). An adjustment greater than 5 mm was required at least once in the treatment period in 11 (55%) patients. CONCLUSIONS: Interportal adjustment of table position was required in more than 10% of portal irradiations during the 10-minute period after initial setup to maintain treatment accuracy within 2.0 mm.
• Stereotactic radiotherapy for intracranial nonacoustic schwannomas including facial nerve schwannoma.

  Nishioka K, Abo D, Aoyama H, Furuta Y, Onimaru R, Onodera S, Sawamura Y, Ishikawa M, Fukuda S, Shirato H

  Int J Radiat Oncol Biol Phys 75 5 1415 - 1419 2009年12月 [査読有り][通常論文]
   

  Purpose: Although the effectiveness of stereotactic radiosurgery for nonacoustic schwannomas is currently being assessed, there have been few studies on the efficacy of stereotactic radiotherapy (SRT) for these tumors. We investigated the long-term outcome of SRT for nonacoustic intracranial nerve schwannomas. Methods and Materials: Seventeen patients were treated between July 1994 and December 2006. Of these patients, 7 had schwannomas located in the jugular foramen, 5 in the trigeminal nerve, 4 in the facial nerve, and I in the oculomotor nerve. Radiotherapy was used as an initial treatment without surgery in 10 patients (59 %) and after initial subtotal resection in the remaining patients. The tumor volume ranged from 0.3 to 31.3 mL (mean, 8.2 mL). The treatment dose was 40 to 54 Gy in 20 to 26 fractions. The median follow-up period was 59.5 months (range, 7.4-122.6 months). Local control was defined as stable or decreased tumor size on follow-up magnetic resonance imaging. Results: Tumor size was decreased in 3 patients, stable in 13, and increased in I after SRT. Regarding neurologic symptoms, 8 patients (47 %) had improvement and 9 patients were unchanged. One patient had an increase in tumor size and received microsurgical resection at 32 months after irradiation. No patient had worsening of pre-existing neurologic symptoms or development of new cranial nerve deficits at the last follow-up. Conclusions: SRT is an effective alternative to surgical resection for patients with nonacoustic intracranial nerve schwannomas with respect to not only long-term local tumor control but also neuro-functional preservation. (C) 2009 Elsevier Inc.

MISC

• 当院における転移性脳腫瘍への術後定位照射症例の検討

  高橋 周平, 森 崇, 打浪 雄介, 西岡 健太郎, 青山 英史, 茂木 洋晃, 山口 秀 Japanese Journal of Radiology 42 (Suppl.) 10 -10 2024年02月
• AFP上昇を伴う未熟奇形腫の治療

  山口秀, 伊師雪友, 大木聡悟, 茂木洋晃, 長谷河昌孝, 寺下友佳代, 平林真介, 西岡健太郎, 橋本孝之, 真部淳, 藤村幹 小児の脳神経(Web) 49 (2) 2024年
• 北大病院放射線治療科関連施設における乳癌の放射線治療に関するアンケート結果リンパ節領域に対する照射について

  木下 留美子, 田口 大志, 高橋 周平, 宮崎 智彦, 森 崇, 西岡 健太郎, 橋本 孝之, 青山 英史 北海道外科雑誌 68 (2) 163 -164 2023年12月
• 【臨床脳腫瘍学-最新の診断・治療と病態-】脳腫瘍の治療 脳腫瘍の放射線療法・他 放射線療法 概論

  青山 英史, 西岡 健太郎, 橋本 孝之 日本臨床 81 (増刊9 臨床脳腫瘍学) 362 -366 2023年12月
• 膀胱癌に対するアテゾリズマブ併用放射線療法 第II相医師主導多施設共同治験

  関野 雄太, 石川 仁, 南雲 義之, 木村 友和, 牛島 弘毅, 山下 英臣, 二瓶 圭二, 富田 夏夫, 吉尾 浩太郎, 吉武 忠正, 西岡 健太郎, 溝脇 尚志, 櫻井 英幸, 西山 博之 日本癌治療学会学術集会抄録集 61回 O39 -1 2023年10月
• 尿管癌への放射線治療後に転移による直腸狭窄を来した1例

  服部 敬寛, 西岡 健太郎, 橋本 孝之, 大塚 愛美, 木下 留美子, 青山 英史, 安部 崇重, 大澤 崇宏, 松本 隆児, 菊地 央, 篠原 信雄, 高桑 恵美 Japanese Journal of Radiology 41 (Suppl.) 4 -4 2023年02月
• 肝細胞癌陽子線治療効果予測におけるADC値指標の検討

  藤田 祥博, 加藤 徳雄, 打浪 雄介, 田口 大志, 西岡 健太郎, 森 崇, 安田 耕一, 小泉 富基, 大塚 愛美, 高尾 聖心, 田村 昌也, Sutherland Kenneth, Khin Khin Tha, 伊藤 陽一, 青山 英史 Japanese Journal of Radiology 41 (Suppl.) 10 -10 2023年02月
• 強度変調回転照射法(VMAT)で術後照射を行った2例

  木下 留美子, 檜垣 朔, 藤田 祥博, 森 崇, 西岡 健太郎, 橋本 孝之, 青山 英史, 押野 智博, 高橋 将人, 加藤 扶美, 金平 孝博 北海道外科雑誌 67 (2) 162 -163 2022年12月
• 放射線治療を中心としたがん治療について-最近の変化と将来- 膠芽腫に対する免疫反応を考慮した照射野最適化の必要性

  西岡 健太郎, 高橋 周平, 森 崇, 打浪 雄介, 山口 秀, 木下 学, 山品 将祥, 前林 勝也, 青山 英史 日本医学放射線学会秋季臨床大会抄録集 58回 S345 -S345 2022年08月
• 免疫チェックポイント阻害薬と放射線治療—Clinical evidences for the combination of immune checkpoint inhibitor and radiation therapy—特集 がん免疫療法の展望 : 免疫チェックポイント阻害薬の併用療法に中心に ; 免疫チェックポイント阻害薬の併用療法のエビデンス

  安田 耕一, 志藤 元泰, 小泉 富基, 高橋 周平, 藤田 祥博, 大塚 愛美, 宮﨑 智彦, 西川 昇, 打浪 雄介, 森 崇, 西岡 健太郎, 木下 留美子, 田口 大志, 加藤 徳雄, 橋本 孝之, 青山 英史 腫瘍内科 = Clinical oncology / 腫瘍内科編集委員会 編 30 (1) 23 -28 2022年07月
• HyperArcを用いた多発性脳転移腫瘍に対する脳定位放射線治療中の各標的の位置ずれに関する検討

  山田 亮太, 吉村 高明, 若林 倭, 金平 孝博, 森 崇, 西岡 健太郎, 青山 英史 日本放射線技術学会総会学術大会予稿集 78回 161 -162 2022年03月
• がん治療における緩和的放射線治療の評価と普及啓発のための研究 放射線治療を含むがん治療の経済毒性と両立支援に関する研究

  青山英史, 白土博樹, 西岡健太郎, 岩崎由加子, 高橋健夫, 原田英幸, 立石清一郎, 内海暢子, 浅川勇雄 がん治療における緩和的放射線治療の評価と普及啓発のための研究 令和3年度 総括・分担研究報告書(Web) 2022年
• 中小企業等における治療と仕事の両立支援の取り組み促進のための研究「治療と仕事の両立支援」に資する大学病院モデルの構築

  白土博樹, 西岡健太郎, 岩崎由加子, 渋谷麻実, 本多和典, 梶本祐介, 五十嵐中, 五十嵐中 中小企業等における治療と仕事の両立支援の取り組み促進のための研究 令和3年度 総括・分担研究報告書(Web) 2022年
• 小児がんに対する陽子線再照射

  橋本孝之, 森崇, 西岡健太郎, 打浪雄介, 安田耕一, 木下留美子, 田口大志, 加藤徳雄, 清水伸一, 青山英史 日本小児血液・がん学会雑誌(Web) 58 (2) 2021年
• 肝細胞癌陽子線治療前MRIにおけるばらつきの小さいADC値指標の検討:治療効果予測に向けた前段階の研究

  藤田祥博, 加藤徳雄, 田口大志, 打浪雄介, 西岡健太郎, 森崇, 湊川英樹, 安田耕一, 清水伸一, 青山英史 日本放射線腫瘍学会高精度放射線外部照射部会学術大会プログラム・抄録集 34th 2021年
• 陽子線治療—Proton therapy for prostate cancer—特集 前立腺癌診療update : 最新の診断と治療 ; 診断と治療

  清水 伸一, 西岡 健太郎, 橋本 孝之 日本臨床 = Japanese journal of clinical medicine 78 (6) 977 -982 2020年06月
• 前立腺がんの陽子線治療—Proton therapy for prostate cancer—特集 泌尿器がんの新しい放射線治療戦略 ; 前立腺がん

  清水 伸一, 橋本 孝之, 西岡 健太郎 泌尿器科 = Urology / 泌尿器科編集委員会 編 11 (4) 386 -391 2020年04月
• 画像誘導陽子線治療の将来展望

  田口大志, 橋本孝之, 橋本孝之, 加藤徳雄, 木下留美子, 安田耕一, 西岡健太郎, 西岡健太郎, 森崇, 打浪雄介, 宮本直樹, 高尾聖心, 清水伸一, 清水伸一, 青山英史 日本癌治療学会学術集会(Web) 58th 2020年
• 筋層浸潤性膀胱癌に対する膀胱温存治療後患者のHealth-related quality of life

  大澤崇宏, 安部崇重, 西岡健太郎, 菊地央, 松本隆児, 橋本孝之, 清水伸一, 青山英史, 村井祥代, 篠原信雄 日本泌尿器内視鏡学会(Web) 34th P -1 2020年
• Bladder-preserving therapy using a real-time tumor-tracking radiotherapy system for muscle-invasive bladder cancer.

  Haruka Miyata, Takahiro Osawa, Jun Frumido, Hiroshi Kikuchi, Ryuji Matsumoto, Takashige Abe, Satoru Maruyama, Kentaro Nishioka, Shinichi Shimizu, Takayuki Hashimoto, Hiroki Shirato, Nobuo Shinohara JOURNAL OF CLINICAL ONCOLOGY 37 (7) 2019年03月 [査読無し][通常論文]
  
• Big Data Analysis of Treatment Process Time for the Real-Time-Image Gated-Spot-Scanning Proton-Beam Therapy (RGPT) System

  T. Yoshimura, S. Shimizu, T. Hashimoto, N. Katoh, T. Inoue, K. Nishioka, T. Matsuura, S. Takao, M. Tamura, H. Tamura, K. Horita, K. Umegaki, H. Shirato International Journal of Radiation Oncology*Biology*Physics 102 (3) e501 -e502 2018年11月 [査読有り]
  
• 前立腺癌治療の新たな展開:ハイリスク前立腺癌に対する拡大手術、粒子線治療、ネオアジュバント治療 ハイリスク前立腺がんに対する強度変調放射線治療・陽子線治療 現状と可能性

  清水 伸一, 橋本 孝之, 西岡 健太郎, 安部 崇重, 大澤 崇宏, 松本 隆児, 松浦 妙子, 宮本 直樹, 高尾 聖心, 鈴木 隆介, 梅垣 菊男, 篠原 信雄, 白土 博樹 日本癌治療学会学術集会抄録集 56回 SY5 -2 2018年10月 [査読無し][通常論文]
  
• リンパ脈管筋腫症(LAM)を合併した乳癌に対し乳房温存術後に術後照射を施行した2例

  木下留美子, 長江伸樹, 西岡健太郎, 橋本孝之, 清水伸一, 白土博樹, 加藤扶美, 石田直子, 山下啓子, 清水薫子, 鈴木雅, 今野哲 北海道外科雑誌 63 (2) 150 -151 2018年
• 動体追跡陽子線治療における前立腺位置変動の解析

  TAMURA Hiroshi, TAMURA Hiroshi, SHIMIZU Shinichi, NISHIOKA Kentaro, HASHIMOTO Takayuki, YOSHIMURA Takaaki, MATSUO Yuto, MATSUURA Taeko, MATSUURA Taeko, TAKAO Seishin, UMEGAKI Kikuo, UMEGAKI Kikuo, SHIRATO Hiroki 医学物理 Supplement 38 (1) 2018年
• 【放射線治療情報BOOK 2016】(DIVISION 4)より高精度の照射のために CLINICAL REPORT iGold 前立腺癌・肝癌における体内金属マーカー

  西岡 健太郎 Rad Fan 14 (14) 94 -94 2016年11月 

  iGoldは北海道大学病院とメディキット株式会社が共同開発した日本初の位置決め用金属マーカーのキット製品で、現在前立腺癌および肝癌の放射線治療時に使用できる。マーカーが真球であることから三次元座標を正確に算出可能であり、動体追跡能力にも優れることから、位置決めの精度の点でゴールデンスタンダードと言える。(著者抄録)
• Treatment Time and Dose Rate Analysis for Respiratory Moving Liver Tumor Using Real-time-image Gated Spot Scanning Proton Beam Therapy System

  SHIMIZU Shinichi, KATOH Norio, TAKAO Seishin, MATSUURA Taeko, MIYAMOTO Naoki, HASHIMOTO Takayuki, NISHIOKA Kentaro, YOSHIMURA Takaaki, UMEGAKI Kikuo, SHIRATO Hiroki 日本医学放射線学会総会抄録集 75th S225 -S225 2016年02月29日 [査読無し][通常論文]
  
• 骨盤部CBCT画像での臓器輪郭描出に関する検討

  西岡 健太郎, 白土 博樹 Japanese Journal of Radiology 32 (Suppl.) 7 -7 2014年02月
• A margin model to account for respiration-induced tumour motion and its variability

  Catherine Coolens, Steve Webb, H. Shirato, K. Nishioka, Phil M. Evans PHYSICS IN MEDICINE AND BIOLOGY 53 (16) 4317 -4330 2008年08月 [査読無し][通常論文]
   

  In order to reduce the sensitivity of radiotherapy treatments to organ motion, compensation methods are being investigated such as gating of treatment delivery, tracking of tumour position, 4D scanning and planning of the treatment, etc. An outstanding problem that would occur with all these methods is the assumption that breathing motion is reproducible throughout the planning and delivery process of treatment. This is obviously not a realistic assumption and is one that will introduce errors. A dynamic internal margin model (DIM) is presented that is designed to follow the tumour trajectory and account for the variability in respiratory motion. The model statistically describes the variation of the breathing cycle over time, i. e. the uncertainty in motion amplitude and phase reproducibility, in a polar coordinate system from which margins can be derived. This allows accounting for an additional gating window parameter for gated treatment delivery as well as minimizing the area of normal tissue irradiated. The model was illustrated with abdominal motion for a patient with liver cancer and tested with internal 3D lung tumour trajectories. The results confirm that the respiratory phases around exhale are most reproducible and have the smallest variation in motion amplitude and phase (approximately 2 mm). More importantly, the margin area covering normal tissue is significantly reduced by using trajectory- specific margins (as opposed to conventional margins) as the angular component is by far the largest contributor to the margin area. The statistical approach to margin calculation, in addition, offers the possibility for advanced online verification and updating of breathing variation as more data become available.
• Dosimetry of¹⁹²Ir sources in brachytherapy in Japan

  H. Shirato, K. Suzuki, K. Nishioka, W. Ichimura Japanese Journal of Clinical Radiology 36 425 -431 1991年01月01日 [査読無し][通常論文]
  

所属学協会

• 日本メディカルAI学会   日本定位放射線治療学会   日本脳腫瘍学会   日本泌尿器腫瘍学会   米国放射線腫瘍学会   日本放射線腫瘍学会   日本医学放射線学会   

共同研究・競争的資金等の研究課題

• 適応放射線治療における線量合算の定量評価と不確かさ低減のための統合的アプローチ

  日本学術振興会：科学研究費助成事業

  研究期間 : 2024年04月 -2027年03月 

  代表者 : 小橋 啓司, 橋本 孝之, 吉村 高明, 西岡 健太郎
• 肺癌に対する陽子線治療の選択基準確立に向けた心肺相互作用勘案NTCPモデル構築

  日本学術振興会：科学研究費助成事業

  研究期間 : 2022年04月 -2025年03月 

  代表者 : 青山 英史, 鈴木 隆介, 宮本 直樹, 高尾 聖心, 金平 孝博, 橋本 孝之, 小橋 啓司, 西岡 健太郎, 田口 大志
• AIを活用した小児がん陽子線照射のトリプルハイブリッド遠隔治療計画システムの開発

  日本学術振興会：科学研究費助成事業

  研究期間 : 2022年04月 -2025年03月 

  代表者 : 橋本 孝之, 高尾 聖心, 小橋 啓司, 吉村 高明, 西岡 健太郎
• 画像上同定困難な表在性腫瘍を人工知能で自動描出する技術の開発

  日本学術振興会：科学研究費助成事業 若手研究

  研究期間 : 2021年04月 -2025年03月 

  代表者 : 西岡 健太郎

   

  内視鏡によって膀胱腫瘍を切除した場合、CT画像上で視覚的に残存している腫瘍の範囲を特定することが困難である。近年の人工知能技術の進歩により臓器全体の輪郭を自動抽出することは可能となってきたが、切除後に平坦になった病変部の自動描出は実現していない。本研究は変形レジストレーションを用いることで画像上特定困難な病変範囲の教師データを作成し、それを用いて学習させた人工知能のセグメンテーションで病変を高速かつ高精度に自動描出する技術を開発することが目的である。 令和3年度は研究の準備段階として、Aidemy社のオンライン講習を受講して人工知能に関する技能を習得した。講習では本研究に関わるセグメンテーションに関する内容は十分ではなかったが、コンピュータ言語(Python)のコード記述法や人工知能に用いるためのデータハンドリング/データクレンジングの他、画像認識・自然言語処理・アプリケーション作成の技能等を習得することができ、本研究を進めるにあたり有用であった。受講の成果物として、インターネット上から収集した画像 1032枚を用いて画像に写っている植物を自動分類するアプリケーションを作成した。開発の際、コード記述のためにVisual Studio Codeを使用し、人工知能の学習と評価にはGoogle Colaboratoryを使用した。その他、本研究の対象となる症例のリストアップ・セグメンテーションモデルに関する情報収集・人工知能開発の環境構築を開始した。
• 陽子線CT搭載型ヘリウム・陽子線混合治療装置と免疫賦活照射法の研究開発

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  研究期間 : 2019年04月 -2024年03月 

  代表者 : 白土 博樹, 宮本 直樹, 高尾 聖心, 梅垣 菊男, 茶本 健司, Nam JinMin, 小野寺 康仁, 松浦 妙子, 西岡 健太郎, 橋本 孝之, 平田 雄一, 田中 創大, 清水 伸一

   

  ① 2019年度に決定した、短時間（0.1秒以下）でエネルギー変更可能な小型加速器の基本設計に基づき、小型加速器の要素技術の設計を行い、短時間（0.1秒以下）でエネルギー変更を可能とする回転ガントリーを含む照射・輸送系の磁場制御設計を行った。 ② 陽子からヘリウムに短時間で加速粒子を変更できる混合加速方式を検討、2023年度に制作開始するべく、陽子線CTの機器としての仕様を検討した。 ③ 陽子線CT値-ヘリウムSPR変換プロセスと、X線CT値利用時の精度を比較し、高エネルギー陽子線CTに必要な要素機器と制御方式の仕様を明確化した。 ④ 高エネルギー陽子線ビームを照射する場合に、ビームの人体への入射方向を意図的に偏心させ、ノズルの外側から照射野中心に向かったビームアングルとするための加速器・照射系の検討を行った。 ⑤ PD-1阻害剤およびPD-L1阻害剤を用いて、がん細胞の制御に最適なLET、ROSとミトコンドリアの分布を計測し、放射線と阻害剤の組み合わせによる相関を検討した。T細胞のPD-1阻害に関する条件検討を行っていたところ、当初の想定に反し、がん細胞での観察と類似の条件ではT細胞の観察が困難であることが判明した。T細胞を観察した上で条件決定することが不可欠であるため、T細胞のPD-1阻害に関する条件決定のための追加検討事項として、培養条件や使用する蛍光色素の種類を複数追加し、T細胞を観察するための至適条件の検討を行った。
• 微小空間画像による極低侵襲・マーカーレス実時間画像誘導放射線治療技法の開発

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  研究期間 : 2018年04月 -2021年03月 

  代表者 : 清水 伸一, 宮本 直樹, 高尾 聖心, 梅垣 菊男, 橋本 孝之, 木下 留美子, 吉村 高明, 西岡 健太郎, 加藤 徳雄, 田口 大志, 松浦 妙子

   

  本研究は、陽子線治療ガントリー設置動体追跡装置の2軸X線透視装置を発展させ、現状より更に低侵襲で尚且つ腫瘍や体内臓器の空間的・時間的変動や呼吸性移動を考慮したがん治療が実現できる実時間画像誘導放射線治療システムを創造することを目的としている。 動体追跡装置では2方向X線透視画像から特徴点の3次元位置座標をリアルタイムに計算し、様々な呼吸位相から治療計画に用いたのものと同じ呼吸位相を時間的に演算によって切り出しゲーティング治療を実現している。透視X線は治療放射線を照射する時間以外にも待機的に用いられているため本来不要な被曝が生じており、特徴点の抽出・認識にマーカを使用する必要があるため、観血的手技が必要などの患者負担が生じている。 まず初年度の実績として、マーカを用いずにゲーティング治療を行う手法についての特許出願を行った(特願2019-056069, 2019)。この特許出願は本研究で想定している特徴点近傍に領域を絞って情報を得て判断を行う画像認識手法を用いており、実際に治療を行う際に必須の物となる。正常組織の線量負荷を低減することの臨床的意義を検証する研究を実施した。 次に次年度の研究活動として、実時間画像誘導放射線治療をダイナミックMRI画像を用いて行うための研究推進体制の検討並びに市場調査等を行い、将来的に実用的に用いることができるものとなるかどうか実装可能性の検討を企業研究者との間で行った。また、透視X線被曝を極限までに低減するための手法について検討を行った。
• 人工知能を用いて管腔臓器の位置および形状を予測・追跡する技術の開発

  日本学術振興会：科学研究費助成事業 若手研究

  研究期間 : 2018年04月 -2021年03月 

  代表者 : 西岡 健太郎

   

  管腔臓器のように体内で位置や形状が日々変化する臓器に対して放射線治療を行う場合、当初計画した照射野と日々の治療時の体内臓器の位置・形状などが一致しない恐れがある。本研究は管腔臓器に対して放射線治療を行う際の精度を向上するため、MRI画像を教師データとして人工知能の学習を行ったうえで臓器の位置や形状の変化を予測・追跡する技術を開発することを目的としている。 2019年度は、後方視的研究として過去に撮像された骨盤部MRI画像を100症例分収集し、膀胱のラベリングを行った。収集した画像数は1060枚で、すべて同一MRI装置で撮像された同一条件の画像であり、ラベリングは本研究計画者が行った。収集した画像のうち840枚(80症例分)の元画像とラベル画像を教師データとし、113枚(10症例分)を訓練用データ、107枚(10症例分)を評価用データとして機械学習を行った。学習にはU-netと呼ばれる二次元畳み込みニューラルネットワークを用いた。人工知能が作成したラベル画像と研究者が作成したラベル画像の一致性はダイス係数と呼ばれる一致性の指標で評価した。ダイス係数は0～100％で表され、0％が完全不一致、100％が完全一致を意味する。機会学習および評価の結果、人工知能はダイス係数94.4％の精度で膀胱のラベル描出をすることに成功した。スライスによって低いダイス係数を認めており、いずれも膀胱の辺縁のスライスであったことから、partial volume effectによる膀胱輪郭の不明瞭化が原因と考えた。この問題に対して三次元畳み込みニューラルネットワークの導入が精度向上に有用であると考えている。
• 4D-CBCTと治療計画CTの容積マッチング法による4D-IGRTの試み

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  研究期間 : 2015年04月 -2018年03月 

  代表者 : 清水 伸一, 梅垣 菊男, 高尾 聖心, 松浦 妙子, 宮本 直樹, 西岡 健太郎, 木下 留美子, 加藤 徳雄

   

  陽子線治療ガントリー内に設置した動体追跡装置の2軸X線透視装置を活用し、腫瘍の空間的・時間的変動や呼吸性移動を考慮したがん治療ができる4D-IGRT放射線治療システム構築を目的として、動体追跡装置の透視画像から4次元コーンビームCT(4D-CBCT)画像を得て、複数の呼吸位相で構成される4D-CBCT画像群の中から、治療計画に用いたCT画像と同じ呼吸位相にあるCT画像から選択するとともに、選択されたCBCT画像を構成する元画像群を用いてマーカーレス4D-RTを目指す発展的画像誘導システムを開発することを目標とした。