Malamut C, Rogers D W, Bielajew A F
Institute for National Measurement Standards, National Research Council Canada, Ottawa.
Med Phys. 1991 Nov-Dec;18(6):1222-8. doi: 10.1118/1.596594.
Using the EGS4 Monte Carlo simulation program, a general purpose code has been written to calculate Bragg-Gray and Spencer-Attix stopping-power ratios for use in radiation dosimetry. The stopping-power ratios can be calculated in any material in any region in a general cylindrical geometry with a large number of source geometries possible. The calculations take into account for the first time the differences between the stopping powers and the inelastic scattering of positrons and electrons. The results show that previous calculations ignoring these effects were accurate. The present results agree, typically within 0.1%, with the Spencer-Attix water-to-air stopping-power ratios for broad parallel beams of electrons given in the AAPM and IAEA protocols except at the surface where the present calculations follow the buildup of secondary electrons in more detail and see a 2% reduction in the stopping-power ratios.
使用EGS4蒙特卡罗模拟程序，编写了一个通用代码，用于计算辐射剂量学中使用的布拉格-格雷和斯宾塞-阿蒂克斯阻止本领比。阻止本领比可以在具有大量可能源几何形状的一般圆柱几何结构的任何区域中的任何材料中进行计算。这些计算首次考虑了正电子和电子的阻止本领以及非弹性散射之间的差异。结果表明，之前忽略这些效应的计算是准确的。除了在表面处，当前结果与AAPM和IAEA协议中给出的宽平行电子束的斯宾塞-阿蒂克斯水-空气阻止本领比通常在0.1%以内相符，在表面处当前计算更详细地跟踪二次电子的积累，并且阻止本领比降低了2%。
