广义平均数学公式在射野等效中的应用  

Generalized mean mathematical for emulator calculation of equivalent square fields

作　　者：李金凯 史玉静 孙新臣 宋威[2] 于大海[2] LI Jinkai SHI Yujing SUN Xinchen SONG Wei YU Dahai(Department of Radiotherapy, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China Radiotherapy Center, Jiangsu Province Hospital of TCM, Nanjing 210029, China)

机构地区：[1]南京医科大学第一附属医院放疗科,江苏南京210029 [2]江苏省中医院放疗中心,江苏南京210029

出　　处：《中国医学物理学杂志》2017年第9期893-896,923,共5页Chinese Journal of Medical Physics

摘　　要：目的:研究利用广义平均数学公式计算等效方野的可能性。方法:选择两台不同厂家的电子直线加速器,分别实际测量6 MV开放野的81个射野输出因子。利用广义平均数学公式s=(βx+(1-β)y~α)^(1/α)计算等效方野,并通过射野输出因子的普适函数公式评价其射野等效计算的准确性。结果:广义平均数学公式对两台加速器射野等效后,射野输出因子的计算精度均小于1%,优于传统经验公式的2%~5%。结论:广义平均数学公式具有通用性,且射野等效精度优于传统经验公式,但需针对特定的应用条件进行数据拟合,以确定最佳的变量值。Objective To test the feasibility of using generalized mean（GM） mathematical formula for calculation of equivalent square（ES） fields. Methods The 81 field output factors（OUFs） in a 6-MV open field were measured with two electron linear accelerators from different manufacturers. The ES were calculated with the GM mathematical formula s =α√βx＋（1-β）y^α）, and the accuracy was evaluated by ubiquitous computing of the OUFs. Results The application of GM mathematical formula for calculation of the ES of the two accelerators showed a deviation less than 1% for calculation of the OUFs, better than the 2%-5% using traditional empirical formulae. Conclusion The GM mathematical formula can be used universally for ES calculation with a better accuracy than the traditional empirical formula, but data fitting is needed for specific conditions to determine the best variable value.

关 键 词：射野大小 等效方野 射野输出因子 广义平均数学公式 普适函数公式 

分 类 号：O29[理学—应用数学]