Andreo P, Nahum A E
Phys Med Biol. 1985 Oct;30(10):1055-65. doi: 10.1088/0031-9155/30/10/004.
Stopping-power ratios for water to air, Sw,air, have been calculated for 60Co and thin-target bremsstrahlung beams. The Monte Carlo method was used to generate depth-dependent Sw,air values and depth-absorbed-dose distributions in water for monoenergetic photon beams covering the energy range 0.1-50 MeV. An averaging procedure has been developed to derive the stopping-power ratios for a photon spectrum from the monoenergetic data. Values of the Spencer-Attix ratio for delta = 10 keV, SSAw,air (delta = 10 keV), and the Bragg-Gray ratio, SBGw,air, evaluated using the new I values and two different sets of values for the density effect correction, are given at the reference depths recommended in the dosimetry protocols.
已针对钴 - 60 和薄靶轫致辐射束计算了水对空气的阻止本领比 Sw,air。采用蒙特卡罗方法生成了能量范围为 0.1 - 50 MeV 的单能光子束在水中随深度变化的 Sw,air 值和深度吸收剂量分布。已开发出一种平均程序，以便从单能数据推导出光子能谱的阻止本领比。在剂量测定协议推荐的参考深度处，给出了使用新的 I 值以及两组不同的密度效应校正值评估得到的 δ = 10 keV 时的斯宾塞 - 阿蒂克斯比 SSAw,air(δ = 10 keV) 和布拉格 - 格雷比 SBGw,air。
