关键词: 
重离子治癌 /
剂量优化 /
CT图像 /
适形照射

摘要: 针对深部肿瘤重离子治疗临床试验的需求，首先在水介质中进行生物有效剂量的优化计算，然后根据CT图像中像素CT值与水等效长度转换系数之间的关系， 结合水中的深度剂量分布曲线对每个像素进行积分得到CT图像上的生物有效剂量分布。同时介绍了基于被动式束流配送系统适形照射时的剂量确定方式， 并提出二维适形放疗也应使用分层照射方式以适应治疗时的不同要求。 这些方法适合目前及今后在IMP进行的重离子治癌临床试验研究中治疗计划系统的需要。Basic algorithms of biological effective dose optimization and dose distribution on CT image for the heavy ion therapy project at the Institute of Modern Physics (IMP)， Chinese Academy of Sciences (CAS) are reported in this paper. Firstly， biological effective dose optimization is conducted in water. According to the relationship between CT number and water equivalent path length， an integral algorithm is used to calculate the average dose within a pixel and then the dose distribution in tissue is derived. Secondly， the dose determination of layerstacking conformal irradiation is described and the layerstacking method is proposed to be applied in twodimensional conformal irradiation. These methods are sufficient to the requirements of the ongoing and future heavyion clinical trials conducted at IMP.