质子束中光束质量校正因子的蒙特卡罗导出:对 Geant4 版本的比较
Guillaume Gabriel Houyoux1, Kilian-Simon Baumann2, Nick Reynaert3
1Faculty of Medicine, Université Libre de Bruxelles, Lenniksebaan 808, Brussels, 1070, BELGIUM.
Biomedical physics & engineering express
|January 8, 2026
概括
新Geant4对质子疗法的模拟表明,虽然11.2版本的光束质量校正因数 (kQ) 与旧版本不同,但目前的不确定性意味着两者都适用于电离室剂量计.
科学领域:
- 医学物理 医学物理
- 辐射剂量计 辐射剂量计
- 蒙特卡洛模拟的蒙特卡洛模拟
背景情况:
- 质子束剂量计的TRS-398行为准则 (CoP) 基于蒙特卡洛 (MC) 模拟和实验数据.
- 束质量校正因子 (kQ) 对于在质子疗法中使用电离室准确地确定剂量至关重要.
- 之前的MC结果使用Geant4版本v10.3和v10.4;本研究调查了最新版本v11.2.2.的影响.
研究的目的:
- 评估使用Geant4版本11.2与早期版本 (v10.3) 相比,对质子束的kQ因子计算的影响.
- 评估模拟工具更新对剂量测量协议的准确性和可靠性的影响.
主要方法:
- 使用Geant4版本10.3和11.2.2.4对四个电离室的kQ因子推导出室特异性质子贡献 (fQ).
- 在两个Geant4版本之间比较了总吸收剂量值和初级和二级颗粒的剂量贡献.
- 分析了kQ值的偏差,特别关注二次离子的物理.
主要成果:
- 与v10.3相比,Geant4 v11.2产生了较高的每颗事件粒子吸收剂量值,特别是在高质子能 (150-250 MeV) 的情况下.
- kQ值的偏差高达1%,主要归因于对二次离子的更新物理模型.
- 在Geant4版本之间最显著的差异是在电离室的入口窗口或外中观察到的.
结论:
- 尽管在Geant4版本之间观察到MC计算的fQ值的偏差,但目前Wair值的不确定性允许在kQ水平上达成协议.
- 使用Geant4 v10.3和v11.2推导的kQ值与现有的TRS-398 CoP数据保持一致.
- 目前,无法对 Geant4 v10.3 和 v11.2 进行 kQ 计算进行明确的区分,这表明两者都是合适的.
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