Development of a phenomenological RBE model for carbon ion radiotherapy and high-precision clinical analysis

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K08188
• 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: International University of Health and Welfare (2022); National Institutes for Quantum Science and Technology (2019-2021)
• Principal Investigator: Kohno Ryosuke 国際医療福祉大学, 保健医療学部, 教授 (20392227)
• Co-Investigator(Kenkyū-buntansha): 鈴木 雅雄 国立研究開発法人量子科学技術研究開発機構, 放射線医学総合研究所 放射線障害治療研究部, 上席研究員(定常) (70281673)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 炭素線治療 / LET / RBE / 臨床解析

Outline of Final Research Achievements

The dose-averaged LET (LETd) calculation tool for clinical analysis of patients treated with carbon-ion radiotherapy (CIRT) was developed. The head and neck patients treated with CIRT were analyzed by this calculation tool. For prescribed RBE-weighted dose of 64 Gy (RBE) in adenoid cystic carcinoma (ACC) patients, we observed the minimum LETd was a determinant of local control (p<0.05). For the optic neuropathy, it was obvious that the optic neuropathy had a greater effect from RBE-weighted dose rather than dose-averaged LET. A phenomenological RBE calculation model based on the LETd was simply paramterised and developed by fitting in vitro experimental data in the literature with data from our experiments.

Free Research Field

医学物理

Academic Significance and Societal Importance of the Research Achievements

本研究は、炭素線治療の有用性を評価しただけでなく、高精度な臨床解析により、局所制御や有害事象に関わる新たな因子を明らかにすることができた。これは炭素線治療の理解を深める興味深い成果であり、本研究の学術的意義は高い。加えて、実測ベース型RBE計算モデルの開発は、任意の組織に対する生物線量の計算を可能にすることから、炭素線治療のより一層の治療成績の向上に繋がる可能性を示すものであり、社会的意義も高い。