Development of PET-based treatment verification in particle therapy

2021 Fiscal Year Final Research Report

• 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
• Keywords: 粒子線治療 / PET / 生物学的洗い出し / 動態解析

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.

Free Research Field

放射線治療と診断

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。