使用蒙特卡洛模拟对C系列线性加速器的光子目标降解的剂量效应
Yongjin Deng1, Minmin Qiu1, Jiajian Zhong1
1Department of Radiation Oncology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Journal of applied clinical medical physics
|August 21, 2025
概括
线性加速器目标降解对光束输出和配置有重大影响. 射线输出和大场对角偏差是检测放射治疗期间目标降解的关键指标.
科学领域:
- 医学物理
- 辐射瘤学
- 放射治疗物理
背景情况:
- 线性加速器目标降解对光束剂量学的影响尚不清楚.
- 为了保持放射治疗的准确性和患者的安全性,调查目标降解至关重要.
研究的目的:
- 确定线性加速器中检测目标降解的最佳剂量指标.
- 分析目标降解对光束剂量参数的影响.
主要方法:
- 使用EGSnrc蒙特卡洛模拟来建模Varian Novalis Tx线性加速器.
- 通过在光子目标中引入真空区域来模拟各种目标降解场景.
- 对光束输出,百分比深度剂量 (PDD),光束形状,相对输出因子 (ROF) 和子因子 (WF) 的评估影响.
主要成果:
- 实际降解 (0.6-0.7 mm深度,1.0-2.0 mm宽度) 将6MV光束输出减少了5.7%-24.1%.
- 观察到形偏差和PDD变化,PDD20,10在30厘米场的1%内发生变化.
- 在退化条件下,患者特异性质量保证 (PSQA) 显示显著下降 (例如90. 9%的马通过率).
结论:
- 开发并验证了一种模拟线性加速器目标降解的蒙特卡洛方法.
- 光束输出和大场对角形偏差 (在0.95场大小) 对目标降解最敏感.
- 这些参数可用于检测临床实践中的目标降解.
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