摆位误差对立体定向放射治疗计划剂量学验证的影响  

Effects of setup errors on dosimetric verification of stereotactic body radiotherapy plan

作　　者：李玉成[1,2] 陈维军 单国平 赵凯[3] 史国栋[3] 邵凯南[3] 李浦[3] 杨一威[3] 陈祥[1] 程品晶 LI Yucheng;CHEN Weijun;SHAN Guoping;ZHAO Kai;SHI Guodong;SHAO Kainan;LI Pu;YANG Yiwei;CHEN Xiangt;CHENG Pinjing(Shool of Nuclear Science and Technology,University of South China,Hengyang 421001,China;Department of Radiotherapy,Zhejiang Provincial People＇s Hospital,Hangzhou 311400,China;Department of Radiation Physics,Zhejiang Cancer Hospital,Hangzhou 311400,China)

机构地区：[1]南华大学核科学技术学院,湖南衡阳421001 [2]浙江省人民医院放疗科,浙江杭州311400 [3]浙江省肿瘤医院放射物理室,浙江杭州311400

出　　处：《中国医学物理学杂志》2018年第8期869-873,共5页Chinese Journal of Medical Physics

基　　金：国家重点研发计划(2017YFC0113201);浙江省医药卫生科技计划项目(2017PY014)

摘　　要：目的:分析立体定向放射治疗(SBRT)患者中摆位误差对剂量学验证结果的影响。方法:分别对14例肺癌患者进行SBRT计划设计,并将计划移植到Delta4剂量验证模体中进行剂量计算,在Varian Trilogy加速器上进行照射,通过移动治疗床模拟患者左(+X)、右(-X)、头(+Y)、脚(-Y)、腹(+Z)、背(-Z)方向上1、3、5 mm的摆位误差,对这6个方向γ通过率的相关性进行分析,从而在γ(3%/3 mm,2%/2 mm)两个标准情况下验证摆位误差对剂量验证通过率的影响。结果:γ(2%/2 mm)参数下仅摆位误差为1 mm时的右方向和脚方向与原计划相比差异无统计学意义(P>0.05);γ(3%/3 mm)参数下摆位误差为1 mm时所有方向与原计划相比差异均无统计学意义(P>0.05)。当摆位误差为1 mm时各方向的两个标准的γ通过率均>90%;当摆位误差为3 mm时,γ(3%/3 mm)的右、脚、腹和背方向的γ通过率>90%,其它方向以及γ(2%/2mm)标准下的γ通过率均<90%;当摆位误差为5 mm时,各方向的两个标准的γ通过率均<90%,头方向γ(2%/2 mm)通过率降为(35.29±8.40)%。结论:摆位误差对于SBRT计划的剂量学验证有较大的影响,标准越严格,摆位误差对验证通过率的影响越明显。Objective To analyze the effects of setup errors on dosimetric verification of stereotactic body radiotherapy（SBRT）in patients with lung cancer. Methods SBRT plans were designed for 14 patients with lung cancer, and then transplanted to Delta4 phantom for dose calculation. The irradiation was implemented on Varian Trilogy linear accelerator. The setup errors were simulated by moving the treatment couch to the left（＋X）, right（-X）, head（＋Y）, foot（-Y）, ventral（＋Z）, back（-Z） by 1, 3 and5 mm. The relationships of gamma passing rate in the 6 directions were analyzed for verifying the effects of setup errors on dose verification under different gamma criteria（3%/3 mm, 2%/2 mm）. Results Only when the setup error was 1 mm, the differences in the right and foot directions had no statistical significance as compared with original plan under the gamma criterion of 2%/2 mm（P〉0.05）, and no statistical significance was found in all directions under the gamma criterion of 3%/3 mm（P〉0.05）. When the setup error was 1 mm, the gamma passing rates were all greater than 90% under the two gamma criteria（3%/3 mm, 2%/2 mm）. When the setup error was 3 mm, only the gamma passing rates in the direction of right, foot, ventral and back were greater than 90%. When the setup error was 5 mm, the gamma passing rates were all less than 90% under the two gamma criteria（3%/3 mm, 2%/2 mm）, and the total passing rate of head direction were decreased to（35.29±8.40）%. Conclusion Setup error has great effects on the dosimetric verification of SBRT plan. The finer the gamma criteria are, the more obvious the effects of setup error on the gamma passing rate are.

关 键 词：立体定向放射治疗 摆位误差 剂量验证 γ通过率 肺癌 

分 类 号：R730.55[医药卫生—肿瘤]