电子FLASH放疗加速器稳定性及三种监视器性能研究  

Study on the stability of electron FLASH radiotherapy accelerator and the performance of three monitors

作　　者：唐镭迅 羊奕伟 王诗岚 程德琪 赵继荣 程品晶[1] Tang Leixun;Yang Yiwei;Wang Shilan;Cheng Deqi;Zhao Jirong;Cheng Pinjing(School of Nuclear Science and Technology,University of South China,Hengyang 421001,China;Institute of Applied Electronics,China Academy of Engineering Physics,Mianyang 621900,China;College of Nuclear Science and Technology,Harbin Engineering University,Harbin 150001,China)

机构地区：[1]南华大学核科学技术学院,衡阳421001 [2]中国工程物理研究院应用电子学研究所,绵阳621900 [3]哈尔滨工程大学核科学与技术学院,哈尔滨150001

出　　处：《中华放射肿瘤学杂志》2024年第8期740-745,共6页Chinese Journal of Radiation Oncology

摘　　要：目的测量中国工程物理研究院应用电子学研究所研制的电子FLASH放疗加速器的束流稳定性并比较闪烁体、快速电流传感器(FCT)和石墨三种监视器在电子FLASH束流下的性能。方法测量电子FLASH放疗加速器在相同工作状态下连续出束时,每次出束和每个脉冲的相对偏差。分别比较加速器在不同电子束能量(通过改变充电电压控制)和不同出束脉冲数时,三种监视器跳数与胶片所测剂量间的拟合决定系数R2,并通过蒙特卡罗模拟程序进行验证。结果在加速器刚加高压时,前10个脉冲的闪烁体和FCT信号都偏大,相较于400个脉冲的平均值,偏差约为2%。在40次出束中,每个脉冲的束流偏差均在±5%以内。在加速器稳定状态下,每次出束的束流偏差均在±1%以内。模拟值和实测值都显示监视器无法用于不同电子束能量下的剂量监测。但在能量相同时,仅改变出束脉冲个数,三种监视器跳数和胶片所测剂量之间呈线性关系(R2均大于0.999)。结论此台电子FLASH加速器每次出束的束流偏差在±1%以内。在电子束能量稳定下,闪烁体、快速电流传感器和石墨可满足对靶区的剂量监测,可为后续生物学试验提供剂量监测参考。ObjectiveTo measure the beam stability of the electron FLASH radiotherapy accelerator developed by the Institute of Applied Electronics of Chinese Academy of Engineering Physics and to evaluate the performance of scintillator,fast current sensor(FCT)and graphite under the electron FLASH beam.MethodsEach continuous beam exit deviation and each pulse deviation at the electron FLASH radiotherapy accelerator in the same working state were measured.The correlation among three monitors and the measured dose of the accelerator at different electron beam energy(controlled by changing the charging voltage)and different beam pulse numbers were compared,which were validated by a Monte Carlo simulation procedure.ResultsAt the first high pressure,the first 10 scintillators and FCT signals were relatively large,approximately 2%deviation compared with the average value of 400 pulses.Among 40 beam outflows,the deviation between each pulse was within±5%.In the accelerator steady state,each beam outflow deviation was within±1%.Both simulated and measured values showed that the monitor could not be used for dose monitoring at different electron beam energy.However,when the energy was the same,only the number of beam pulses was changed,and linear relationship was observed between the number of the three monitors and the dose measured by the film(all R 2>0.999).ConclusionsThe beam deviation of each beam outflow of this electron FLASH accelerator is within±1%.Under the stability of the accelerator beam,the scintillator,FCT and graphite can meet the dose monitoring of the target area,which can provide reference for dose monitoring for subsequent biological experiments.

关 键 词：放射疗法 超高剂量率 剂量监测 蒙特卡罗模拟 

分 类 号：R197.39[医药卫生—卫生事业管理]