基于双能CT的蒙特卡洛质子束剂量计算的基向量模型权重的组织特性推导
Maria Jose Medrano1, Xinyuan Chen2, Lucas Norberto Burigo3
1Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, United States of America.
Biomedical physics & engineering express
|December 1, 2025
概括
一种新方法,基本向量模型材料索引 (BVM-MI),可以准确地预测双能CT扫描的组织组成和密度. 这改进了用于质子疗法规划的蒙特卡洛剂量计算,与传统方法相比,显示了显著的错误减少.
科学领域:
- 医学物理 医学物理
- 放射性成像学成像学
- 计算生物学 计算生物学
背景情况:
- 双能CT (DECT) 提供了超越传统CT的特定材料信息.
- 准确的材料表征对于质子疗法中精确的辐射剂量计算至关重要.
- 像Hounsfield Unit材料索引 (HU-MI) 这样的现有方法在材料差异化方面存在局限性.
研究的目的:
- 引入和评估一种新的方法,即基础向量模型材料索引 (BVM-MI),用于预测原子组成和质量密度.
- 评估BVM-MI对质子疗法中蒙特卡罗 (MC) 剂量规划准确性的影响.
- 将BVM-MI性能与传统HU-MI方法进行比较.
主要方法:
- BVM-MI利用DECT的两个独立的基向量模型重量来预测70种组织的元素组成和质量密度.
- 预测的材料特性被导入到TOPAS MC代码中,用于质子剂量模拟.
- 通过比较BVM-MI和HU-MI,使用元素组成误差,质量密度误差和剂量分配精度 (R80深度,停止功率) 等指标来评估性能.
主要成果:
- 与HU-MI相比,BVM-MI显示出更高的元素组成预测准确性,在软和骨组织中,根平均平方误差 (RMSE) 较低.
- 在预测80%最大得分剂量 (R80) 的深度时,BVM-MI显著减少了错误,RMSE为0.2mm (软) 和0.1mm (骨) 相比于HU-MI的1.8mm和0.7mm.
- 使用BVM-MI的MC剂量计算显示,RMSE在剂量计算中比HU-MI低7至9倍.
结论:
- 在使用DECT数据进行材料表征时,BVM-MI方法比HU-MI显著改进.
- 通过BVM-MI准确的材料索引可以提高质子疗法中MC剂量计算的精度.
- BVM-MI显示了改善质子疗法规划的巨大潜力,特别是对于具有复杂元素组成的组织.
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