Development of PET-based treatment verification in particle therapy

• Project/Area Number: 18K07773
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Tokyo Women's Medical University
• Principal Investigator: Toramatsu Chie 東京女子医科大学, 医学部, 講師 (90421825)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
• Keywords: 粒子線治療 / PET / 生物学的洗い出し / 動態解析 / Theranostics / autoactivation / in beam PET / washout effect / particle therapy / washout / PETイメージング / 生物学的洗い出し効果 / 整体洗い出し効果

Outline of Final Research Achievements

In dose verification techniques of particle therapies based on PET, the causes of washout of positron emitters by physiological effects should be clarified. Therefore, we measured the biological washout rate of implanted 11C and 15O beams on rabbit brains using our original PET. The experimental data suggested that implanted 11C beam forms 11CO2, 11CO …etc, and washed out due to blood perfusion and taken up into pulmonary circulation. The washout rate of implanted 15O was equivalent with cerebral blood flow (CBF) which was measured by 15O-labeled water. These results suggested that implanted 15O beam may react to form H2O15 and diffused out. In summary, the difference of diffusion process in the 11C and 15O beams was observed. This study provided new data to investigate the biological washout mechanism.

Academic Significance and Societal Importance of the Research Achievements

PETを用いた線量分布検証の精度には生物学的洗い出しによる制限がある。しかしその機序が不明であるため正確なモデル化はされていない。また、主な信号は15Oと11Cであるが、これまで11Cの照射実験によるモデルしか提案されていなかった。本研究では核種により生物学的洗い出し機序と速度が異なることを示し、正しいモデルの構築に向けて有用なデータが得られた。本研究の成果を臨床応用に発展させることで、患者の高精度放射線治療に役立つと考えられる。

Research Products

• [Journal Article] Biological washout effect in in-beam PET: animal studies. (2020)
  • Author(s): Chie Toramatsu, Akram Mohammadi, Hidekatsu Wakizaka, Fumihiko Nishikido, Chie Seki, Iwao Kanno, Shinji Sato, Kumiko Karasawa, Yoshiyuki Hirano and Taiga Yamaya
  • Journal Title: Journal of Physics: Conference Series. Vol. 1662. No. 1 Volume: 1662 Pages: 012032-012033
  • Open Access / Int'l Joint Research
• [Journal Article] Biological washout modelling for in-beam PET: rabbit brain irradiation by 11C and 15O ion beams. (2020)
  • Author(s): Chie Toramatsu, Akram Mohammadi, Hidekatsu Wakizaka, Fumihiko Nishikido, Chie Seki, Iwao Kanno, Shinji Sato, Kumiko Karasawa, Yoshiyuki Hirano and Taiga Yamaya
  • Journal Title: Physics in Medicine & Biology Volume: 65 Pages: 105011-105022
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Biological washout modelling for in-beam PET: rabbit brain irradiation by ¹¹C and ¹⁵O ion beams (2020)
  • Author(s): Chie Toramatsu, Akram Mohammadi, Hidekatsu Wakizaka, Chie Seki, Fumihiko Nishikido, Shinji Sato, Iwao Kanno, Miwako Takahashi, Kumiko Karasawa, Yoshiyuki Hirano and Taiga Yamaya
  • Journal Title: Physics in Medicine & Biology Volume: in press
  • Peer Reviewed
• [Journal Article] Washout effect in rabbit brain: in-beam PET measurements using 10C, 11C and 15O ion beams (2018)
  • Author(s): Chie Toramatsu, Eiji Yoshida, Hidekazu Wakizaka, Akram Mohammadi, Yoko Ikoma, Hideaki Tashima, Fumihiko Nishikido, Atsushi Kitagawa, Kumiko Karasawa, Yoshiyuki Hirano and Taiga Yamaya
  • Journal Title: Biomedical physics & Engineering Express Volume: 4 Pages: 2-10
  • Peer Reviewed
• [Presentation] Measurement of biological washout rates depending on tumor vascular status in 15O in-beam rat PET (2021)
  • Author(s): C. Toramatsu, A. Mohammadi, H. Wakizaka, C. Seki, F. Nishikido, S. Sato, I. Kanno, M Takahashi and T. Yamaya
  • Organizer: IEEE
  • Int'l Joint Research
• [Presentation] Biological washout effect in in-beam PET: animal studies (2020)
  • Author(s): Chie Toramatsu, Akram Mohammadi, Hidekatsu Wakizaka, Fumihiko Nishikido, Chie Seki, Iwao Kanno, Shinji Sato, Kumiko Karasawa, Yoshiyuki Hirano and Taiga Yamaya
  • Organizer: MMND ITRO 2020
  • Int'l Joint Research / Invited
• [Presentation] Can biological washout rate be a biomarker of tumor viability in charged particle therapy? A rat in-beam PET study. (2020)
  • Author(s): Chie Toramatsu, Akram Mohammadi, Hidekatsu Wakizaka, Fumihiko Nishikido, Chie Seki, Iwao Kanno, Shinji Sato, Kumiko Karasawa, Yoshiyuki Hirano and Taiga Yamaya
  • Organizer: Japan Society of Medical Physics
• [Presentation] BIOLOGICAL WASHOUT EFFECT IN IN-BEAM PET : ANIMAL STUDIES (2020)
  • Author(s): Chie Toramatsu
  • Organizer: MMND-ITRO 2020
  • Int'l Joint Research / Invited
• [Presentation] Compartmental analysis of biological washout effect in rabbit brain:In-beam PET measurements using 15O and 11C beams (2019)
  • Author(s): Chie Toramatsu
  • Organizer: PTCOG 58th annual meeting
  • Int'l Joint Research
• [Presentation] 粒子線照射時の原子核破砕反応により発生する陽電子放出核の放射性薬物 動態解析 (2019)
  • Author(s): 寅松千枝
  • Organizer: 日本放射線腫瘍学会 第32回学術大会
• [Presentation] in-beam PET measurement of washout in rabbits using 11C and 15O ion beams: Study of in vivo kinetics of induced particles (2018)
  • Author(s): 寅松千枝
  • Organizer: 60th Annual Meeting & Exhibition of the American Association of Physicists in Medicine
  • Int'l Joint Research
• [Presentation] Study of Kinetics of Induced Particle: in-beam PET measurement of washout in rabbits using 11C and 15O ion beams (2018)
  • Author(s): 寅松千枝
  • Organizer: 第116回日本医学物理学会学術大会
  • Int'l Joint Research