Jursinic P A, Mueller R
Battle Creek Health System, Department of Radiation Oncology, Michigan 49016, USA.
Med Phys. 1997 Nov;24(11):1765-9. doi: 10.1118/1.597962.
An empirical model is presented that uses a sector-integration method for calculating the output factors of irregularly shaped electron fields. The sector-integration method accounts for changes in electron fluence, lateral scatter equilibrium, and scatter from the edge of a cutout shield. This method is tested for elliptical and rectangular fields with a ratio of the long-to-short axis as great as 4 to 1. Differences between measured and calculated values for output factors were less than +/- 1%. Comparisons were also carried out for a large number of cutout shields that were used in the clinic and similar levels of accuracy were obtained.
提出了一种经验模型，该模型采用扇形积分法来计算不规则形状电子射野的输出因子。扇形积分法考虑了电子注量的变化、侧向散射平衡以及来自挡块边缘的散射。该方法针对长轴与短轴之比高达4比1的椭圆形和矩形射野进行了测试。输出因子的测量值与计算值之间的差异小于±1%。还对临床中使用的大量挡块进行了比较，获得了类似的准确度水平。
