Wielopolski L, Pai S, Mlyn M
Department of Radiation Oncology, University Hospital, Stony Brook, New York 11794.
Med Phys. 1991 May-Jun;18(3):559-64. doi: 10.1118/1.596745.
The tables of the mean restricted collision mass stopping power ratios for water, polystyrene and acrylic relative to air given in the AAPM TG-21 protocol have been fitted to an expression with 20 coefficients using the depth in the phantom and the mean incident electron energy as two independent variables. Using these expressions, the calculated values agree with the tabulated values within +0.5% in 85% of the cases and within +/- 1.0% in 95% of the cases. For each of the four cylindrical chamber inner diameters, given in the protocol, the electron fluence correction Prepl has been fitted to an expression with four coefficients using the mean electron energy at depth z as an independent variable.
美国医学物理学家协会（AAPM）TG - 21协议中给出的水、聚苯乙烯和丙烯酸相对于空气的平均受限碰撞质量阻止本领比的表格，已通过使用模体深度和平均入射电子能量作为两个独立变量，拟合为一个具有20个系数的表达式。使用这些表达式，在85%的情况下，计算值与表格值的偏差在±0.5%以内，在95%的情况下，偏差在±1.0%以内。对于协议中给出的四个圆柱形电离室内径中的每一个，电子注量校正Prepl已通过使用深度z处的平均电子能量作为独立变量，拟合为一个具有四个系数的表达式。
