次级准直器对左乳腺癌放射治疗剂量的影响  

Effect of Secondary Collimator on Radiotherapy Dose for Left Breast Cancer

作　　者：徐云 李自康 Xu Yun;Li Zikang(Ya'an People's Hospital,Sichuan University West China Hospital Ya'an Hospital,Ya'an Sichuan 625000,China)

机构地区：[1]四川大学华西医院雅安医院·雅安市人民医院,四川雅安625000

出　　处：《医疗装备》2023年第23期19-22,共4页Medical Equipment

摘　　要：目的研究次级准直器对左乳腺癌放射治疗剂量的影响。方法利用蒙特卡罗程序(BEAMnrc)模拟电子和光子在医用直线加速器治疗头中的输运行为,然后利用BEAMdp对相空间文件进行分析,获得次级准直器对光子能谱及剂量的影响。使用Oncentra计划系统,选取2020年1月至2023年6月医院左乳腺癌患者100例设计放射治疗计划,分析次级准直器的角度对放射治疗计划靶区及重要危及器官的影响。结果通过分析标称能量为6MV的医用直线加速器的光子能谱,发现次级准直器单一X、Y方向和整体次级准直器光子数占总光子数比例均不到0.2%,表明次级准直器对光子剂量影响较小;通过改变次级准直器的角度,发现左乳腺癌放射治疗计划左肺V_(20)、V_(30)和D_(mean)分别降低了1.49%、1.48%和6.35%,此外心脏V_(10)、V_(30)和D_(mean)分别降低了2.11%、1.59%和7.95%。结论在设计左乳腺癌放射治疗计划时,可通过改变次级准直器的角度降低患者左肺及心脏受照剂量。Objective To study the effect of secondary collimator on photon dose and radiotherapy dose for left breast cancer.Methods Use the BEAMnrc code to simulate the transport of electrons and photons in treatment head of the medical linac,where a phase space file is generated by the simulation at the scoring plane.Analyze the phase space and obtain the photon energy spectrum and dose about the secondary collimator.Using the Oncentra planning system to design left breast cancer radiotherapy plans for 100 patients.By changing the angle of secondary collimator,compare the effect of radiotherapy dose for left breast cancer plans.Results About the 6 MV photon energy spectrum,the photon number of single X,Y direction and the whole secondary collimator accounted for less than 0.2%of the total photon number.By changing the angle of the secondary collimator,it was found that the left lung of V_(20)、V_(30) and D_(mean) is decreased by 1.49%(P<0.05),1.48%(P<0.05)and 6.35%(P<0.05),besides the heart of V_(10)、V_(30) and D_(mean) is decreased by 2.11%(P<0.05),1.59%(P<0.05)and 7.95%(P<0.05).Conclusion Changing the angle of the secondary collimator can reduce the dose of left lung and heart radiation dose in left breast cancer radiotherapy plan.

关 键 词：光子 次级准直器 左乳腺癌 

分 类 号：R815[医药卫生—放射医学]