高能电子线放射治疗的剂量学参数测量与分析  

Dosimetry and Analysis of Electron Beam Irradiation

作　　者：翁邓胡[1] 徐海荣[1] 

机构地区：[1]南方医科大学生物医学工程学院,广东广州510515

出　　处：《中国医学物理学杂志》2012年第2期3250-3253,共4页Chinese Journal of Medical Physics

基　　金：广东省科技三项(No.K1022032);广东省自然科学基金(No.K1021034)

摘　　要：目的:对高能电子线总输出因子、百分深度剂量、深度剂量分布的剂量学参数进行测量并分析讨论。方法:在Varian23EX直线加速器上,利用9606剂量测量仪和0.6 cc指型电离室测量不同能量、不同限光筒及不同射野下的输出剂量并作归一,得到我们所要的剂量学参数,然后分析数据。结果:总输出因子在不同能量下与正方形射野边长的关系可满足等式:y=a.ebx+c.edx。水模体百分剂量分布中,6 MeV电子线各限光筒的90%、85%等剂量深度基本不变,9 MeV^15 MeV下90%、85%等剂量深度随着限光筒尺寸增大而变深。对于水模体的深度剂量分布情况,6 MeV和12 MeV能量的10 cm×10 cm、15 cm×15 cm限光筒均整区内对称点的最大相对剂量差分别都为0.04%、0.03%。结论:通过测量掌握实际照射中的剂量学特点,对于电子线剂量的准确计算以及临床计划制定具有很大的参考价值。Objective： To measure and analyse dosimetric characteristics of the total output,the percentage depth doses and the dose distribution at depth for high energy electron beam. Methods： Using 9606 electrometer and 0.6 cc ion chamber,we measured the dose rate for different energy, different applicator sizes and different block fields by linear accelerator Varian 23EX. We got the dose parameters by normalization,then analysed datas. Results： The relationship between total output factor and square field side in different energy meet the equation （y=a. e^bxX＋c .e^dx）.Under the percentage depth dose distribution of water phantom,90% ,85% isodose depth with different applicator sizes were unchanged basically for 6 MeV. However,the isodose depth was increasing with the cone size enlarging for 9 MeV-15 MeV. With regard to the dose distribution at depth,the flatness region symmetric point of maximum relative dose difference in 10 cm×10 cm and 15 cm×15 cm applicators were 0.04% and 0.03% respectively for 6 MeV/12 MeV. Conclusions： By measuring and mastering the dosimetric characteristics in an actual irradiation,this will have a great reference value in calculating the accurate dose and making clinical plans.

关 键 词：电子线照射 总输出因子 电离室 剂量分布 

分 类 号：R815[医药卫生—放射医学]