Monte Carlo方法在核辐射医学中的应用

Applications of Monte Carlo method in radiation medicine

在放射性治疗(外照射或内照射)疑难病症(如癌症)及重症病过程中,病体所受剂量及其分布是治疗过程中必须考虑的问题。当射线进入人体后各部分受到的剂量必须要进行理论计算。射线在人体内的反应机制是光子和电子偶合输运过程,非常复杂,一般数值方法难于求解。Monte Carlo方法是解决本类问题十分有效的方法。该文将Monte Carlo方法应用到核辐射医学中,叙述了两种体内剂量场分布的Monte Carlo计算方法:沉积能量法和通量转换法。为了提高计算效率,给出了几种实用的技巧。最后,介绍了一个应用实例。

In the radiation treatment process of difficulty disease such as cancer,the precise dose distribution in the body must be considered.Little dose makes no sense,much dose would harm the body.The theoretic calculation must be done before the treatment.The reaction mechanism is complicated,including the coupled transport of photons and electrons.The solution is hard to get from the common numerical method.On the contrary,the Monte Carlo method is the useful technique to solve this kind of problem.The article describes the application of Monte Carlo method in radiation medicine,and expatiates two Monte Carlo methods in the dose distribution calculation of the body.For improving the calculating efficiency,some applied techniques are presented.At last,there is one example.