基于面元模型的河蚌剂量转换系数的计算

Hybrid phantom of mussel for calculation of dose conversion coefficients

基于河蚌开口与闭合两种形态,利用多边形网格(PM)与NURBS曲线技术对河蚌体素模型进行光滑和变形处理,分别建立河蚌开口面元模型和闭合面元模型,并通过MCNPX模拟计算河蚌在两种模型形态下的外照射剂量转换系数(外照射DCC)与内照射剂量转换系数(内照射DCC)。通过模拟结果可得出:(1)在外照射条件下,河蚌的外照射DCC的关系为:开口面元模型>闭合面元模型;(2)在内照射条件下,河蚌的内照射DCC的关系为:闭合面元模型>开口面元模型。

A hybrid phantom of mussel has been developed for radiation protection of the environment. Based on the Polygon Mesh（ PM） and non-uniform rational B-spline（ NURBS） surfaces,the phantom was created from the same data set of CT images with open and closed shell to evaluate dose conversion coefficients（ DCC）.137 Cs in the water for external exposure and90 Sr in the organism for internal exposure were both simulated for the mussel in open and closed state by the Monte Carlo simulations. The results showed that,for external exposure,DCC of the mussel in the open state were larger than those of the closed state while in the case of internal exposure it was quite the contrary. It confirmed that deformation of the organs could cause different absorbed dose rates.