前列腺癌患者调强放疗中的摆位误差及其对剂量分布影响分析  

The study about the setup error and its effect on dose distribution in IMRT for prostate cancer patients

作　　者：高璇[1] 李克新[1] 鞠永健[1] 曹丽媛[1] GAO Xuan;LI Kexin;JU Yongjian;CAO Liyuan(Department of Radiation Oncology,The First People＇s Hospital of Nantong City,Nantoag 226001 China)

机构地区：[1]江苏省南通市第一人民医院放疗科,江苏南通226001

出　　处：《中国辐射卫生》2018年第3期228-230,251,共4页Chinese Journal of Radiological Health

基　　金：国家自然科学基金资助项目(10705016);南通市社会事业科技创新与示范计划(HS2012036)

摘　　要：目的分析前列腺癌患者IMRT中的摆位误差及其对剂量分布的影响。方法对45例前列腺癌患者IMRT时行CBCT确定移床坐标,计算获得摆位误差后分为A(σ≤6 mm)、B(σ>6 mm)两组,比较两组患者年龄、体重指数、膀胱和直肠体积变化的差异。并根据移床坐标移床后治疗计划系统计算获得的剂量参数,比较45例患者原计划和移床后计划靶区及危及器官的剂量参数差异。结果 45例患者的X、Y、Z方向移床坐标分别为(0.020±0.407)、(-0.031±0.424)、(-0.107±0.273)cm;以摆位误差分组时,A组23例与B组22例患者的BMI差异有统计学意义,而年龄、膀胱和直肠体积改变差异均无统计意义;移床前后45例患者的靶区参数PTV95、PTV平均剂量、CTV95、CTV平均剂量、膀胱V60差异均有统计学意义,而直肠V60及股骨头V20差异未见统计学意义。结论前列腺癌患者调强放疗时需关注摆位误差,而摆位误差可能与患者BMI有关,与年龄、膀胱直肠体积变化等关系不大,治疗时需通过移床进行校正,否则会造成靶区及危及器官剂量分布与原始计划存在差异。Objective To Analyze the setup error and its effect on dose distribution in IMRT for prostate cancer patients. Methods 45 prostate cancer patients underwent CBCT as the first treatment and compared with the original treatment plan to get the value of bed shifting. Then the setup error were calculated though these values, and patients were divided into two groups, A （≤6mm） and B （ 〉 6mm）. Then the patients＇differences of age, BMI, bladder and rectum volume changes in A and B were compared. Also after bed shifting, the dose parameters of target and OARS were recalculated and compared with that calculated from original treatment plan. Results 1. The bed shifting values in X, Y and Z directions of 45 patients are 0. 020 ±0. 407 cm, -0.031±0. 424 cm and -0. 107±0. 273 cm individually. 2. The difference of BMI between A （23 pa- tients） and B （22 patients ） has statistically significant, but the difference of age, bladder and rectum volume changes have no statistically significance. 3. Compared the close parameters between original plan and latter plan after shifting the treatment bed, the differences of PTV95, the average dose of PTV, CTV95, average dose of CTV and the hladder V60 all have statisti- cally significance, But the differences of rectum V60 and femoral head V20 have no significant difference. Conclusion In prostate cancer patients IMRT,the setup error must be care about, it may be related to the patient＇s BMI, but has limited/no relationships with the ageand bladder rectal volume changes in this study, and it must be corrected by shifting treatment bed, otherwise it will cause the dose distribution error in the target area and OARs.

关 键 词：CBCT 摆位误差 剂量分布 

分 类 号：R144.1[医药卫生—公共卫生与预防医学]