波束质量和电网辐射治疗中较低的百分比深度剂量背后的奥秘
Amir Hossein Karimi1,2, Indra J Das3, Nahid Chegeni4
1Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Scientific reports
|February 24, 2024
概括
空间分离辐射疗法 (SFRT),或网格疗法,对大容量瘤有希望. 蒙特卡洛模拟证实标准剂量计协议可以使用,尽管在网格领域的低深度剂量.
科学领域:
- 医学物理 医学物理
- 辐射瘤学 辐射瘤学
背景情况:
- 空间分离辐射疗法 (SFRT),也称为网格疗法或格子疗法,由于有前景的结果,正在为治疗庞大的瘤获得吸引力.
- 使用定制块或多叶合器实施SFRT带来了剂量测量方面的挑战,特别是在网格领域观察到的较低的百分比深度剂量 (PDD).
研究的目的:
- 调查网格疗法的剂量测量特性,特别是针对较低的PDD和组织幻影比率 (TPR20/10) 适用于光束质量评估的适用性.
- 评估使用标准剂量计协议用于网格治疗领域的可行性.
主要方法:
- 使用MCNPX代码进行蒙特卡洛 (MC) 模拟,对6 MV线性加速器束进行模拟.
- 使用商用电网疗法装置来模拟电网场,并与MC模拟对光束参数进行验证.
- 电子和光子光谱在开放和网格场之间进行了比较.
主要成果:
- 最大剂量的深度 (dmax) 在开放和网格字段之间保持一致.
- 与开放场相比,PDD在网格场中大约低10%,这是由于散射辐射的深度流动性减少.
- TPR20/10显示了约5%的差异,表明它仍然是网格领域光束质量评估的可靠指数.
- 网格领域的输出因子比开放领域低0.2.
结论:
- 尽管较低的深度剂量和输出因子,电网疗法剂量计没有显著影响.
- 对于开放光束而建立的标准剂量计协议可以可靠地应用于网格治疗领域.
- TPR20/10是电网领域光束质量的有效指标,支持使用现有的校准方法.
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