水模体与固体水刻度直线加速器时的比较与分析  

Comparison and Analysis of Accelerator Scaled by Water Phantom and Solid Water

作　　者：李青革 李平英 邵辉柏 Li Qingge;Li Pingying;Shao Huibo(Department of Radiotherapy,The Third Hospital of Nanchang,Nanchang Jiangxi 330009,China;Department of Radiotherapy,The 334 Affiliated Hospital of Nanchang University,Nanchang Jiangxi 330009,China)

机构地区：[1]南昌市第三医院放疗科,江西南昌330009 [2]南昌大学附属三三四医院放疗科,江西南昌330009

出　　处：《医疗装备》2021年第3期26-27,30,共3页Medical Equipment

摘　　要：目的比较与分析水模体与固体水刻度直线加速器测量结果的差异。方法使用PTW水箱和IBA固体水,在相同的测量条件下,分别对瓦里安23EX直线加速器的6、10 MV X线及6、9、12、15、18 MeV多档电子线,在相应测量深度处进行绝对剂量的测量,取多次测量平均值,最后再除以各档能量相应测量深度处的百分深度剂量,进而转换为射野中心轴上最大剂量点处的点剂量。结果使用固体水与水模体刻度直线加速器6、10 MV和6、9、12、15、18 MeV各档射线,两种方法的相对偏差分别为-0.23%、-0.56%、3.89%、-5.71%、-4.41%、-4.39%、-4.26%;两者的等效因子分别为1.002、1.006、0.963、1.061、1.046、1.046、1.045。结论日常质控工作中,可使用固体水代替水模体刻度直线加速器,但在使用之前,需先使用水模体进行刻度,得到等效因子以校正固体水的刻度结果。Objective The test results'differences of accelerator scaled by water phantom and solid water were compared and analyzed..Methods Under the same measurement conditions,the absolute doses of two-photon beams of 6,10 MV and multi-level electron beams of 6,9,12,15,18 MeV of the Varian accelerator 23EX were all measured repeatedly at the corresponding measurement depths by PTW water phantom and IBA solid water.And then the percentage depth dose at the corresponding depths of each beam were divided by their average values(acquired from the measurement results above),and finally the results were converted into the point dose at the maximum dose point on the center axis of the shooting field.Results When solid water and water phantom were used to calibrate the accelerator at 6,10 MV of two-photon beams and at 6,9,12,15,18 MeV of electron beams,the relative differences between the two methods were-0.23%,-0.56%,+3.89%,-5.71%,-4.41%,-4.39%,-4.26%;the equivalence factors of the two methods were 1.002,1.006,0.963,1.061,1.046,1.046,1.045.Conclusions In daily quality control work,solid water could be used to replace water phantom to calibrate accelerator.While it is necessary to acquire the equivalence factor to revise the calibration results of solid water according to those acquired from water phantom before use.

关 键 词：水模体 固体水 加速器 剂量刻度 

分 类 号：R197.39[医药卫生—卫生事业管理]