电子束输出剂量随射野大小变化规律的探讨  

The Research about the Output Dose Rate Changed with the Size of Electron Beam Fields

作　　者：沈国辉[1] 张书旭[1] 吴少焜[2] 叶育盛[1] 王余锋[1] 

机构地区：[1]广州医学院附属肿瘤医院,广东广州510095 [2]中山大学附属第二医院

出　　处：《中国辐射卫生》2008年第3期272-273,共2页Chinese Journal of Radiological Health

摘　　要：目的探讨电子束射野面积对其输出剂量的影响。方法利用Matrixx平面探测器对西门子Primus直线加速器不同能量、不同电子束限光筒、不同面积射野的输出剂量进行测量,得出数据后用Matlab软件绘制变化规律曲线,并拟合出数学公式。结果当挡块所形成射野大于6cm×6cm时,其输出剂量与10cm×10cm野相比小于3%,而挡块所形成的方野在2cm×2cm～5cm×5cm之间时,输出量随射野大小变化显著变化,最高可达30%。结论各种不同能量电子束的输出因子与挡块所形成的方野边长的关系可满足拟合公式:y=a+k1.emx+k2.e-mx。Objective To investigate the relationship between the output dose and the blocked field size of electron beam. Methods The output dose of different energy and electron beam applicator and blocked fields size of electron beam created were measured with 2D air vented ionization chamber array MatriXX system under a clinac accelerator Primus （ Siemens Medical Solution USA, Inc） , and the measured data were fitted into a mathematic function with Matlab software and the curves of output dose factor were plotted. Results If the blocked field sizes were greater than 6cm × 6cm, the change of the output dose of it was less than 3% among the different size fields, if the blocked fields were between 2cm × 2cm and 5cm × 5cm, the output doses were changed obviously according to the fields size, the maximum change could nearly reach to 30%. Conclusion The relationship between output factor of different energy electron beam field and blocked field sizes could be described with the function y = a ＋ k1· e^mx ＋ k2·e^-mx .

关 键 词：电子束照射 Matrixx平面探测器 射野面积 输出剂量 

分 类 号：R814.2[医药卫生—影像医学与核医学]