放射治疗脑室肿瘤的计算方法研究

Study Computing Method for Radiotherapy of Ventricle Tumor

脑室肿瘤放射治疗剂量分布的实验测量需要利用组织等效模型和系列测量设备、实验技术,测量工作较繁琐,费用高。本工作采用蒙特卡罗理论计算方法。此方法比较简单、灵活,受问题的条件影响不大,对复杂的几何条件,各参数随能量的剧烈变化,散射各向异性等情况均易处理。蒙特卡罗方法的基本思想,是把随机过程的概率特征(随机事件的概率或随机变量的数学期望)与数学分析的解答(积分值,微分方程的解等)联系起来,然后模拟随机过程,用数学期望或概率的估计值作为原分析问题的近似解,亦即用数学模拟的方法确定相应的概率与数学期望值代替毓复杂的分析公式的计算。

In order to measure the dose distribution of radiotherapy of ventricle tumor equivalent tissue models and a series of measure equipments and experimental technology need to be used. And it also results in complicated measure procedure and high costs. M-C computing method is adopted in this paper. It is simpler more flexible and less affected by the conditions of problem. Furthermore it makes it easier to process the following situations complicated geometrical conditions anisotropic scatter and intense parameter variation with energy. Basic idea of M-C computing method is Firstly to combine probability features probability of random incident or mathematical expectation of random variables of random process with solution to mathematic analytical problems integration solution to differential equation. Secondly to simulate random process and regard the estimation of probability and mathematical expectation as the approximate solution to original analytical problems i.e. substitute probability and mathematical expectation determined by mathematical simulation for a series of complicated computation of analytical formulas.