摘要
目的探讨电子束不对称照射野输出因子的变化规律。方法用电离室法对不同大小限光筒不同能量下3个特定照射野按照偏离中心轴不同距离实测其输出因子，计算不对称照射野输出因子与对称照射野输出因子的偏差。结果不对称照射野的输出因子随着偏轴距离的变化规律与所对应限光筒标准方野离轴比的变化基本上是一致的，提示不对称照射野的输出因子与标准方野的离轴比相关。限光筒和铅挡野大小对输出因子偏差值的影响不明显。结论电子束不对称照射野输出因子的变化主要与标准方野的离轴比有关，是否修正可根据标准方野离轴比的变化情况决定。
Objective To evaluate the variant regularity of the output factors of asymmetrical rectangular electron beam field. Methods The output factors of three special fields with different applicators and energies were measured by ionization chamber method at different off-axis distances. Then deviations of the output factors between asymmetrical and symmetric rectangular fields were calculated. Results The changes of output factor with different off-axis distances in asymmetrical rectangular fields were basically consistent with those in standard square fields with the same applicator. It revealed that the output factor of a- symmetrical rectangular field was related with the off-axis ratio of standard square field. Applicator and field size did not show obvious influence on the output factor. Conclusions The output factor changes of asymmetrical rectangular field are mainly correlated with the off-axis ratio of standard square field. The correction of the output factor is determined by the off-axis ratio changes in standard square field.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2009年第5期413-415,共3页
Chinese Journal of Radiation Oncology
关键词
电子束照射
输出因子
不对称照射野
Electron beam radiation
Output factor
Asymmetrical rectangular inserts
