立体定向放射治疗计划不同剂量区间三维γ通过率分析  

Three-dimensional gamma passing rate in different dose ranges for stereotactic body radiotherapy

作　　者：刘颖[1] 孙海涛 邓青萍 袁玲 张红利 徐瑶瑶 张晓鹏 王鑫[1] 石兴源[1] LIU Ying;SUN Haitao;DENG Qingping;YUAN Ling;ZHANG Hongli;XU Yaoyao;ZHANG Xiaopeng;WANG Xin;SHI Xingyuan(Department of Radiotherapy,the Fifth Affiliated Hospital of Guangzhou Medical University,Guangzhou 510700,China;Department of Radiotherapy,Zhongshan Hospital of TCM,Zhongshan 528400,China;Department of Equipment,Huizhou Municipal Central Hospital,Huizhou 516001,China)

机构地区：[1]广州医科大学附属第五医院放射治疗科,广东广州510700 [2]中山市中医院医学影像放疗室,广东中山528400 [3]惠州市中心人民医院设备科,广东惠州516001

出　　处：《中国医学物理学杂志》2021年第12期1508-1517,共10页Chinese Journal of Medical Physics

基　　金：广州市科技计划项目(201905010004)。

摘　　要：目的:为探究立体定向放射治疗(SBRT)剂量通过率的特点及敏感性,分析SBRT验证计划γ通过率。方法:选取38例SBRT计划移植到PTW的OCTAVIUS模体,在Verisoft软件中将PTW 1600SRS采集的二维剂量重建为三维剂量,用Matlab分析Verisoft重建出的三维剂量(Dp)与放射治疗计划系统计算的三维剂量(Dt)间的γ通过率,并分析不同阈值及不同剂量区间内的γ通过率,检验γ通过率对不同剂量区间的剂量增加的敏感度。结果:阈值为10%时,3 mm标准下的γ通过率均大于90%;不同标准下的γ通过率的趋势较一致;3%/3 mm标准下,11%~20%区间内的γ通过率最高,所有γ标准下,51%以上剂量区间内(即照射区内)γ通过率均值低于90%,且波动性极大;γ通过率对51%以下剂量区间内(即照射区外)剂量增加敏感度较高。结论:阈值越小,γ通过率越高;低剂量区的γ通过率高于高剂量区,γ通过率对低剂量区剂量增加较敏感。Objective To explore the characteristics and sensitiveness of gamma passing rate in stereotactic body radiotherapy(SBRT)by analyzing gamma passing rate for stereotactic radiotherapy(SBRT)verification plan.Methods A total of 38 SBRT plans were transplanted to the OCTAVIUS phantom of PTW,and the two-dimensional dose collected by PTW 1600SRS was reconstructed into three-dimensional dose using Verisoft.The gamma passing rates between three-dimensional dose reconstructed by Verisoft(Dp)and that calculated by treatment planning system(Dt)were analyzed by Matlab.In addition,the gamma passing rates under different thresholds and in different dose ranges were analyzed for testing the sensitiveness of gamma passing rate to dose increase in different dose ranges.Results The gamma passing rate at 3 mm criterion was higher than 90%when the threshold was 10%.The gamma passing rates at different criteria were in the same tread.At 3%/3 mm criterion,the highest gamma passing rate was found in the 11%-20%dose range.For all criteria,the mean gamma passing rate in dose range higher than 51%(inside radiation area)was lower than 90%and changed significantly.In dose range lower than 51%(outside radiation area),the gamma passing rate was highly sensitive to dose increase.Conclusion The smaller the threshold is,the higher the gamma passing rate is.The gamma passing rate of low-dose area is higher than that of high-dose area,and gamma passing rate is more sensitive to the dose increase in low-dose area.

关 键 词：立体定向放射治疗 γ通过率 剂量验证 水模体 

分 类 号：R815[医药卫生—放射医学]