前列腺癌放疗定位中膀胱体积的变化对摆位重复性的影响  

Effects of changes in bladder volumes derived from CT simulation on set-up errors during radiotherapy for prostate cancer

作　　者：李展维 黄虹[1] 何梦雪 林茂盛[1] 林承光[1] 迟锋[1] 姚文燕[1] 许森奎[1] Li Zhanwei;Huang Hong;He Mengxue;Lin Maosheng;Lin Chengguang;Chi Feng;Yao Wenyan;Xu Senkui(Department of Radiation Oncology,Sun Yat-sen University Cancer Center,Guangzhou 510060,China)

机构地区：[1]中山大学肿瘤防治中心放疗科,广州510060

出　　处：《中华放射医学与防护杂志》2023年第12期986-990,共5页Chinese Journal of Radiological Medicine and Protection

基　　金：广东省医学科学技术研究基金(A2017613);广东省食管癌研究所科技计划(Q202107)。

摘　　要：目的研究前列腺癌放疗定位膀胱体积对放疗中膀胱体积的一致性和摆位精度的影响,为临床实践提供参考。方法回顾性选取2015年8月至2020年11月在中山大学肿瘤防治中心进行调强放疗的66例前列腺癌患者,患者在CT定位及治疗前自主憋尿后进行定位扫描或执行放疗,每次放疗前行锥形束计算机体层(CBCT)扫描获得左右、头脚和前后平移方向误差。在CT模拟定位影像和CBCT影像上勾画膀胱轮廓并计算体积,根据CT定位影像上膀胱体积进行分组,200~300 ml组18例、300~400 ml组24例、>400 ml组24例,分析CT定位膀胱体积对放疗过程中CBCT膀胱体积相对计划体积的变化百分比和摆位误差的影响。结果200~300 ml组放疗中膀胱体积减少15%,300~400 ml组放疗中膀胱体积减少26%,>400 ml组放疗中膀胱体积减少32%,3组膀胱体积变化百分比两两比较差异均有统计学意义(Z=3.43、7.97、4.83,P<0.05)。三维平移方向摆位误差比较:头脚方向差异有统计学意义(H=26.72,P<0.05),左右、前后方向无统计学意义(P>0.05)。头脚方向摆位误差分别为200~300 ml组:0.00(-0.20,0.20)cm;300~400 ml组:0.00(-0.20,0.30)cm;>400 ml组:-0.10(-0.30,0.20)cm。>400 ml组在头脚方向摆位误差大于其余两组,差异有统计学意义(Z=4.17、4.66,P<0.05),其余差异无统计学意义(P>0.05)。结论模拟定位时膀胱充盈容积控制在200~300 ml,有利于患者在放疗中保持膀胱体积一致性及减少放疗时的摆位误差。Objective To explore the effects of bladder volumes from CT simulation on bladder volume consistency and set-up errors during radiotherapy for prostate cancer,aiming to provide a reference for clinical practice.Methods A retrospective analysis was conducted for of 66 prostate cancer patients treated with intensity-modulated radiation therapy in the Sun Yat-sen University Cancer Center from August 2015 to November 2020.They underwent CT scan or radiotherapy after voluntarily holding in urine.Cone beam computed tomography(CBCT)scans were performed for them to measure their set-up errors in leftright(L-R),superior-inferior(S-I),and anterior-posterior(A-P)directions before each treatment.The bladder contours of the patients were delineated on CT simulation images and CBCT images.Accordingly,bladder volumes were calculated.Based on the calculated bladder volumes derived from the CT simulation images,the patients were divided into three groups:18 cases in the 200-300 ml group,24 cases in the 300-400 ml group,and 24 cases in the>400 ml group.Finally,this study analyzed the effects of bladder volumes derived from CT simulation on set-up errors and the changes of CBCT-derived bladder volumes relative to planned volumes during radiotherapy.Results The bladder volumes in the 200-300 ml,300-400 ml,and>400 ml groups during radiotherapy were reduced by 15%,26%,and 32%,respectively.The pairwise comparison indicates statistically significant differences in the changes of bladder volumes among the three groups(Z=3.43,7.97,4.83,P<0.05).Regarding the three-dimensional set-up errors,there were statistically significant differences in S-I set-up errors among the three groups(H=26.72,P<0.05),but there was no statistically significant difference in L-R and A-P set-up errors(P>0.05)among these groups.The 200-300 ml,300-400 ml,and>400 ml groups exhibited S-I set-up errors of 0.00(-0.20,0.20)cm,0.00(-0.20,0.30)cm,and-0.10(-0.30,0.20)cm,respectively.Therefore,the>400 ml group displayed larger the S-I set-up errors than other two groups,wit

关 键 词：前列腺癌 调强放疗 锥形束CT 膀胱体积 摆位误差 

分 类 号：R737.25[医药卫生—肿瘤]