Researcher Database

Sodai Tanaka
Faculty of Engineering Applied Quantum Science and Engineering Quantum Engineering for Life Science and Medicine
Assistant Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Engineering Applied Quantum Science and Engineering Quantum Engineering for Life Science and Medicine

Job Title

  • Assistant Professor

Degree

  • Ph.D. in Engineering(The University of Tokyo)

J-Global ID

Research Interests

  • Proton Range Uncertainty   Dual-Energy CT   Proton CT   Proton Therapy   Computed Tomography   Radiation Therapy   Medical Physics   

Research Areas

  • Life sciences / Radiology
  • Energy / Quantum beam science
  • Life sciences / Radiology

Academic & Professional Experience

  • 2019/04 - Today Hokkaido University Faculty of Engineering Assistant Professor
  • 2018/04 - 2019/03 Hokkaido University Hospital Department of Medical Physics Assistant Professor
  • 2016/08 - 2016/12 German Cancer Research Center Guest Researcher

Education

  • 2015/04 - 2018/03  The University of Tokyo  School of Engineering  Department of Nuclear Engineering and Management
  • 2013/04 - 2015/03  The University of Tokyo  School of Engineering  Department of Nuclear Engineering
  •        - 2013/03  The University of Tokyo  Faculty of Engineering  Department of Systems Innovation

Association Memberships

  • Young Researchers' Association of Medical Physics   JAPANESE SOCIETY FOR RADIATION ONCOLOGY   JAPAN SOCIETY OF MEDICAL PHYSICS   

Research Activities

Published Papers

  • Naoki Miyamoto, Kouhei Yokokawa, Seishin Takao, Taeko Matsuura, Sodai Tanaka, Shinichi Shimizu, Hiroki Shirato, Kikuo Umegaki
    Journal of applied clinical medical physics 2020/02/18 [Refereed][Not invited]
     
    Spot-scanning particle therapy possesses advantages, such as high conformity to the target and efficient energy utilization compared with those of the passive scattering irradiation technique. However, this irradiation technique is sensitive to target motion. In the current clinical situation, some motion management techniques, such as respiratory-gated irradiation, which uses an external or internal surrogate, have been clinically applied. In surrogate-based gating, the size of the gating window is fixed during the treatment in the current treatment system. In this study, we propose a dynamic gating window technique, which optimizes the size of gating window for each spot by considering a possible dosimetric error. The effectiveness of the dynamic gating window technique was evaluated by simulating irradiation using a moving target in a water phantom. In dosimetric characteristics comparison, the dynamic gating window technique exhibited better performance in all evaluation volumes with different effective depths compared with that of the fixed gate approach. The variation of dosimetric characteristics according to the target depth was small in dynamic gate compared to fixed gate. These results suggest that the dynamic gating window technique can maintain an acceptable dose distribution regardless of the target depth. The overall gating efficiency of the dynamic gate was approximately equal or greater than that of the fixed gating window. In dynamic gate, as the target depth becomes shallower, the gating efficiency will be reduced, although dosimetric characteristics will be maintained regardless of the target depth. The results of this study suggest that the proposed gating technique may potentially improve the dose distribution. However, additional evaluations should be undertaken in the future to determine clinical applicability by assuming the specifications of the treatment system and clinical situation.
  • M.Takabe, T.Masuda, M.Arimoto, J.Kataoka, K.Sueoka, T.Maruhashi. S.Tanaka, T.Nishio. T.Toshito, M.Kimura. T.Inaniwa
    Nuclear Instruments and Methods in Physics Research A 924 332 - 338 2019/04 [Refereed][Not invited]
  • Yusuke Ochi, Akito Saito, Daisuke Kawahara, Tatsuhiko Suzuki, Masato Tsuneda, Sodai Tanaka, Teiji Nishio, Shuichi Ozawa, Yuji Murakami, Yasushi Nagata
    Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) 58 59 - 65 1120-1797 2019/02 [Refereed][Not invited]
     
    PURPOSE: The output of a linear accelerator (linac) is one of the most important quality assurance (QA) factors in radiotherapy. However, there is no quantitative rationale for frequency and tolerance. The purpose of this study is to develop a novel risk analysis of clinical reference dosimetry based on failure modes and effects analysis (FMEA). METHODS: Clinical reference dosimetry data and the daily output data of two linacs (Clinac iX and Clinac 6EX) at Hiroshima University Hospital were analyzed. The analysis involved the number of patients per year for five types of fractionations. Risk priority number (RPN) is defined as the product of occurrence (O), severity (S), and detectability (D) in standard FMEA. In addition, we introduced "severity due to output drifting" (mean output change per day) (S') and the number of patients per year for five types of fractionations (W). We calculated the RPN = O × S × D × S' × W and quantitatively evaluated the risk for clinical reference dosimetry. RESULTS: Fewer fractions and less output calibration frequency resulted in higher RPN. Since clinical reference dosimetry data has a drift effect, which is missing in human processes, it was essential to use S' in addition to standard FMEA. Moreover, the parameter W was important in evaluating interinstitutional QA for clinical reference dosimetry. The relative risk of Clinac 6EX to Clinac iX was different approximately by twofold. CONCLUSIONS: We developed a novel index that can quantitatively evaluate risk for clinical reference dosimetry of each facility and machines in common on the basis of FMEA.
  • Kawahara D, Ozawa S, Tanaka S, Yokomachi K, Higaki T, Saito A, Miki K, Fujioka C, Ohno Y, Ohno Y, Kimura T, Murakami Y, Nagata Y
    The British journal of radiology 91 (1090) 20180396  0007-1285 2018/10 [Refereed][Not invited]
  • Tsuneda M, Nishio T, Saito A, Tanaka S, Suzuki T, Kawahara D, Matsushita K, Nishio A, Ozawa S, Karasawa K, Nagata Y
    Medical physics 0094-2405 2018/04 [Refereed][Not invited]
  • Kawahara D, Ozawa S, Saito A, Kimura T, Suzuki T, Tsuneda M, Tanaka S, Nakashima T, Ohno Y, Murakami Y, Nagata Y
    Journal of applied clinical medical physics 19 (2) 211 - 217 2018/03 [Refereed][Not invited]
  • Kawahara D, Ozawa S, Yokomachi K, Tanaka S, Higaki T, Fujioka C, Suzuki T, Tsuneda M, Nakashima T, Ohno Y, Nagata Y
    The British journal of radiology 91 (1082) 20170524  0007-1285 2018/02 [Refereed][Not invited]
  • Tanaka S, Nishio T, Tsuneda M, Matsushita K, Kabuki S, Uesaka M
    Physics in medicine and biology 63 (3) 035030  0031-9155 2018/02 [Refereed][Not invited]
  • Kawahara D, Nakano H, Ozawa S, Saito A, Kimura T, Suzuki T, Tsuneda M, Tanaka S, Ohno Y, Murakami Y, Nagata Y
    Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) 46 89 - 95 1120-1797 2018/02 [Refereed][Not invited]
  • Kawahara D, Ozawa S, Saito A, Kimura T, Suzuki T, Tsuneda M, Tanaka S, Hioki K, Nakashima T, Ohno Y, Murakami Y, Nagata Y
    Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznan and Polish Society of Radiation Oncology 23 (1) 50 - 56 1507-1367 2018/01 [Refereed][Not invited]
  • Daisuke Kawahara, Shuichi Ozawa, Takeo Nakashima, Tatsuhiko Suzuki, Masato Tsuneda, Sodai Tanaka, Yoshimi Ohno, Yuji Murakami, Yasushi Nagata
    PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS 32 (12) 1628 - 1633 1120-1797 2016/12 [Refereed][Not invited]
     
    Purpose: Nowadays, patient positioning and target localization can be verified by using kilovolt cone beam computed tomography (kV-CBCT). There have been various studies on the absorbed doses and image qualities of different kV-CBCT systems. However, the Varian TrueBeam CBCT (TB CBCT) system has not been investigated so far. We assess the image quality and absorbed dose of TB CBCT through comparison with those of on-board imager (OBI) CBCT. Methods: The image quality was evaluated using two phantoms. A CATPHAN phantom measured the image quality parameters of the American Association of Physicists in Medicine Task Group 142 (AAPM TG-142) report. These factors are the pixel value stability and accuracy, noise, high-contrast resolution, low-contrast resolution, and image uniformity. A H2SO4 phantom was used to evaluate the image uniformity over a larger region than the CATPHAN phantom. In evaluating the absorbed dose, the radial dose profile and the patient organ doses at the prostate and rectum levels were evaluated. Results: The image quality parameters of AAPM TG-142 using TB CBCT are equal to or greater than those of OBI CBCT. In particular, the contrast-to-noise ratio with TB CBCT is 2.5 times higher than that with OBI CBCT. For the test of a large field uniformity, the maximum difference in the Hounsfield unit (HU) values between the centre and peripheral regions is within 30 HU with TB CBCT and 283 HU with OBI CBCT. The maximum absorbed dose with TB CBCT is decreased by 60%. Conclusions: We find that the image quality improved and the absorbed dose decreased with TB CBCT in comparison to those with OBI CBCT. Its image uniformity is also superior over a larger scanning range. (C) 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
  • 西尾禎治, 田中創大, 松下慶一郎, 恒田雅人, 株木重人, 前田宗利, 伊東富由美, 久米恭
    若狭湾エネルギー研究センター研究年報 18 42‐43  2016/10 [Not refereed][Not invited]
  • Sodai Tanaka, Teiji Nishio, Keiichiro Matsushita, Masato Tsuneda, Shigeto Kabuki, Mitsuru Uesaka
    PHYSICS IN MEDICINE AND BIOLOGY 61 (11) 4156 - 4167 0031-9155 2016/06 [Refereed][Not invited]
     
    A proton computed tomography (pCT) imaging system was constructed for evaluation of the error of an x-ray CT (xCT)-to-WEL (water-equivalent length) conversion in treatment planning for proton therapy. In this system, the scintillation light integrated along the beam direction is obtained by photography using the CCD camera, which enables fast and easy data acquisition. The light intensity is converted to the range of the proton beam using a light-to-range conversion table made beforehand, and a pCT image is reconstructed. An experiment for demonstration of the pCT system was performed using a 70 MeV proton beam provided by the AVF930 cyclotron at the National Institute of Radiological Sciences. Three-dimensional pCT images were reconstructed from the experimental data. A thin structure of approximately 1 mm was clearly observed, with spatial resolution of pCT images at the same level as that of xCT images. The pCT images of various substances were reconstructed to evaluate the pixel value of pCT images. The image quality was investigated with regard to deterioration including multiple Coulomb scattering.
  • Uesaka M, Demachi K, Fujiwara T, Dobashi K, Fujisawa H, Chhatkuli R. B, Tsuda A, Tanaka S, Matsumura Y, Otsuki S, Kusano J, Yamamoto M, Nakamura N, Tanabe E, Koyama K, Yoshida M, Fujimori R, Yasui A, IOP
    1st International Conference in Applied Physics and Materials Science 79 (1) 012015  2015 [Refereed][Not invited]
  • T. Fujiwara, S. Tanaka, Y. Mitsuya, H. Takahashi, K. Tagi, J. Kusano, E. Tanabe, M. Yamamoto, N. Nakamura, K. Dobashi, H. Tomita, M. Uesaka
    JOURNAL OF INSTRUMENTATION 8 C12020  1748-0221 2013/12 [Refereed][Not invited]
     
    We recently developed glass gas electron multipliers (G-GEMs) with an entirely new process using photo-etchable glass. The photo-etchable glass used for the substrate is called PEG3 (Hoya Corporation). Taking advantage of low outgassing material, we have envisioned a medical application of G-GEMs. A two-dimensional position-sensitive dosimetry system based on a scintillating gas detector is being developed for real-time dose distribution monitoring in X-ray radiation therapy. The dosimetry system consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside of which G-GEM structures are mounted. Photons produced by the excited Ar/CF4 gas molecules during the gas multiplication in the GEM holes are detected by a mirror-lens-CCD-camera system. We found that the intensity distribution of the measured light spot is proportional to the 2D dose distribution. In this work, we report on the first results from a scintillating G-GEM detector for a position-sensitive X-ray beam dosimeter.

Conference Activities & Talks

  • シンチレータとCCDカメラを用いた線量積算型陽子線CT画像取得法の研究  [Not invited]
    田中創大, 西尾禎治, 恒田雅人, 高部美帆, 増田孝充, 株木重人, 久米恭, 長谷川崇, 上坂充
    日本放射線腫瘍学会第30回学術大会  2017/11
  • Improvement of proton CT imaging system using BGO scintillator and CCD camera  [Not invited]
    S. Tanaka, T. Nishio, K. Matsushita, M. Tsuneda, S. Kabuki, M. Uesaka
    European Congress of Radiology 2017  2017/03
  • Development of proton CT imaging system using thick scintillator and CCD camera  [Not invited]
    S. Tanaka, T. Nishio, K. Matsushita, M. Tsuneda, S. Kabuki, M. Uesaka
    58th Annual Meeting of the American Association of Physicists in Medicine  2016/07
  • Development of proton CT imaging system  [Not invited]
    S. Tanaka, T. Nishio, K. Matsushita, M. Tsuneda, S. Kabuki, M. Uesaka
    European Congress of Radiology 2016  2016/03
  • 陽子線CT画像取得法の確立  [Not invited]
    田中創大, 西尾禎治, 松下慶一郎, 恒田雅人, 株木重人, 上坂充
    日本放射線腫瘍学会第29回高精度放射線外部照射部会学術大会  2016/02
  • 陽子線CT画像取得法の研究  [Not invited]
    田中創大
    Geant4研究会医学応用研究会  2015/12
  • Improvement of proton CT imaging system using BGO scintillator and CCD camera  [Not invited]
    S. Tanaka, T. Nishio, K. Matsushita, M. Tsuneda, S. Kabuki, A. Sugiura, M. Uesaka
    第110回日本医学物理学会学術大会  2015/09
  • Study on proton CT for evaluation of water equivalent length factor  [Not invited]
    S. Tanaka, T. Nishio, K. Matsushita, M. Tsuneda, Y. Aono, S. Kabuki, A. Sugiura, M. Uesaka
    15th International Congress of Radiation Research  2015/05
  • 陽子線治療における体内中飛程計算精度向上のための陽子線CT画像取得法の研究  [Not invited]
    田中創大, 西尾禎治, 松下慶一郎, 中村哲志, 恒田雅人, 青野裕樹, 余語克紀, 株木重人, 上坂充
    日本放射線腫瘍学会第27回学術大会  2014/12
  • Development of proton CT imaging system for evaluation of proton range calculation accuracy  [Not invited]
    S. Tanaka, T. Nishio, K. Matsushita, M. Tsuneda, Y. Aono, S. Kabuki, A. Sugiura, M. Uesaka
    Fourth Joint Meeting of the Nuclear Physics Divisions of the American Physical Society and The Physical Society of Japan  2014/10
  • 陽子線CT画像取得法の研究  [Not invited]
    田中創大, 西尾禎治, 松下慶一郎, 中村哲志, 恒田雅人, 青野裕樹, 余語克紀, 株木重人, 上坂充
    第107回日本医学物理学会学術大会  2014/04
  • シンチレーションガスとGlassGEMを用いたX線がん治療機用リアルタイムビームモニタリングシステムの開発  [Not invited]
    田中創大, 田儀和浩, 藤原健, 高橋浩之, 上坂充, 草野譲一, 中村直樹, 山本昌志, 菅原浩一, 田辺英二
    日本原子力学会2013年春の年会  2013/03
  • シンチレーションガスとGlassGEMを用いたX線がん治療用リアルタイムビームモニタリングシステムの開発  [Not invited]
    田中創大, 田儀和浩, 藤原健, 高橋浩之, 上坂充, 草野譲一, 中村直樹, 山本昌志, 菅原浩一, 田辺英二
    日本原子力学会関東・甲信支部第6回学生研究発表会  2013/03

MISC

Awards & Honors

  • 2018/03 The University of Tokyo Dean's award of graduate school of engineering
     
    受賞者: Sodai Tanaka
  • 2013/03 The Japan Society of Mechanical Engineers Hatakeyama Award
     
    受賞者: Sodai Tanaka

Research Grants & Projects

  • 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
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2019/04 -2024/03 
    Author : 白土 博樹, 宮本 直樹, 平田 雄一, 田中 創大, 高尾 聖心, 梅垣 菊男, 茶本 健司, 清水 伸一, Nam JinMin, 小野寺 康仁, 松浦 妙子
  • スキャニングビーム陽子線CT画像取得法の研究開発
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists
    Date (from‐to) : 2019/04 -2022/03 
    Author : 田中 創大
  • 陽子線CT画像取得法の研究
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
    Date (from‐to) : 2017/04 -2019/03 
    Author : 田中 創大
     
    現在、陽子線治療の治療計画では患者のX線CT画像を基に陽子線の線量計算が行われているが、陽子線飛程計算の不確定性は3%と報告されている。治療で用いる30 cmの飛程の陽子線の場合で9 mmにも及び、ブラックピークの活用による線量集中性が良さである陽子線治療の大きな問題点となっている。その解決手法の1つとして陽子線CT画像の利用があげられ、陽子線と物質の相互作用量をそのままイメージングすることで、前述の3%の不確定性を大きく減少させることができる。陽子線CT画像取得法が確立していない現状に対して、本研究では臨床利用可能な陽子線CT画像取得法の研究開発を行った。検出システムは主に厚いシンチレータとCCDカメラから構成される。陽子線イメージングでは被写体透過前後のエネルギーの差を投影データとして取得するが、本システムでは厚いシンチレータで陽子線を全て停止させ、その発光のビーム方向積算値をCCDカメラで取得することで2次元陽子線エネルギー分布を取得した。また被写体を回転させることにより360度方向からのデータを取得し、再構成することで陽子線CT画像を得た。この手法はシンプルな検出システムでかつ短時間で測定できることが長所である。 シンチレータの種類や実験パラメータなどのハード面と画像処理・再構成手法のソフト面の両面での改善を行い、臨床に用いられている陽子線ビームを用いて検出システムの実証実験を実施することができた。その結果、実験的に本システムで取得できる陽子線CT画像の精度は臨床利用レベルにまで到達した。

Social Contribution

Social Contribution

Others

  • 2016/06 -2016/06 Proton CT could ease treatment planning
    Medical Physics Web http://medicalphysicsweb.org/cws/article/research/65359


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