模体大小对MC程序计算速度与精度的影响研究

Effect of Phantom Dimension Variation on Monte Carlo Simulation Speed and Precision

摘要: 蒙特卡罗程序的计算速度与计算模型的体积大小有一定关联。通过改变模体的厚度，发现除在尾部有限范围内会出现差异外，薄模体与厚模体的结果差别很小，然而却可以获得模拟效率的指数性提升。通过改变模体的宽度，发现窄模体与宽模体相比，只要宽度比照射野半影大，对模拟效率的影响都很小；而当宽度与照射野半影区重合时，效率就有一定程度的提高，同时对剂量结果影响很小。将此研究结果用于临床头部实例，获得了计算速度的显著提升。

Abstract: There is a correlation between Monte Carlo simulation speed and the phantom dimension. The effect of the phantom dimension on the Monte Carlo simulation speed and precision was studied based on a fast Monte Carlo code DPM. The results showed that when the thickness of the phantom was reduced, the efficiency would increase exponentially without compromise of its precision except for the position at the tailor. When the width of the phantom was reduced to outside the penumbra, the effect on the efficiency would be neglectable. However when it was reduced to within the penumbra, the efficiency would be increased at some extent without precision loss. This result was applied to a clinic head case, and the remarkable increased efficiency was acquired.