使用大面积的电离室物理基础和A型不确定性去除质子参考剂量测谱
Hong Qi Tan1,2,3, Kah Seng Lew1,3, Calvin Wei Yang Koh1
1Division of Radiation Oncology, National Cancer Centre Singapore, Singapore, Singapore.
Physics in medicine and biology
|December 17, 2024
概括
在笔束扫描质子疗法中,平滑参考剂量测量可以减少峰值的不确定性. 然而,这种方法可能会增加整体平均不确定性,需要在监视器单元校准时仔细应用.
科学领域:
- 医学物理 医学物理
- 辐射瘤学 辐射瘤学
- 剂量测量方法 剂量测量方法
背景情况:
- 笔束扫描质子疗法可以经历剂量波动由于内部溢出点的位置偏移.
- 与能量对比的噪音参考剂量计测量可以导致监视器单元校准中的错误.
研究的目的:
- 调查平滑基准剂量计测量对A型不确定性的影响.
- 评估装配技术在减少剂量测量噪声方面的有效性.
主要方法:
- 参考剂量测量 (Dw/MU) 用PTW 34045室测量了98个能量层在5天内.
- 使用PTW 34089大型区域电离室 (LAIC) 进行单点辐射 (MspotLAIC) 的同时测量.
- 对Dw/MU和MspotLAIC数据进行线性和二次性拟合,以创建无噪声的参考剂量计曲线.
主要成果:
- 参考剂量计测量的可重复性显示出高达2.3%的相对差异.
- 线性和二次性匹配显示出高相关性 (R2 > 0.95).
- 与测量相比,无噪声曲线的最大A型不确定性较低 (0.69%),但平均不确定性较高 (0.50%),分别为0.88%和0.43%.
结论:
- 将LAIC收费与参考剂量计曲线相匹配,提供了一种在特定能量层中减轻大错误的方法.
- 在降低峰值不确定性时,光滑技术增加了所有能量中的A型平均不确定性.
- 在临床实践中,应谨慎地应用合适的参考剂量计曲线.
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