全身伽马刀与三维适形放疗在原发性肝癌治疗中的剂量分析

摘要

目的:比较全身伽马刀与三维适形放疗在原发性肝癌治疗中的剂量分布,为临床治疗优选方案提供依据.方法:对2014年3月至2015年7月收治的35例采用全身伽马刀治疗的原发性肝癌患者进行三维适形放疗计划设计,用剂量体积直方图评价2个计划靶区和正常组织剂量分布以及靶区适形指数(conformity index,CI)和均匀指数(homogeneity index,HI).结果:对于肿瘤靶区(gross tumor volume,GTV),伽马刀的D98与平均剂量Da均高于三维适形放疗;对于计划靶区(planning target volume,PTV),伽马刀与三维适形放疗V95分别为(95.05±0.02)％与(90.00±0.03)％(P=0.00),伽马刀治疗靶区覆盖率较好;对于危及器官,伽马刀更能保护正常组织;三维适形放疗靶区内剂量均匀性较伽马刀治疗好(GTV:0.11±0.15 vs 0.23±0.02,PTV:0.14±0.04 vs 0.21±0.03),但正常肝组织受照体积过大.结论:全身伽马刀在原发性肝癌的治疗中比三维适形放疗具有剂量学上的优势,但是在肿瘤靶区剂量均匀性方面较三维适形放疗差,在实际治疗中要根据患者的靶区情况选择最佳的治疗方式.%Objectives To compare the dose distribution of the whole body γ-knife and three-dimensional conformal radiotherapy (3D-CRT) in the treatment of primary hepatic carcinoma to provide evidence for clinical treatment choice.Methods Totally 35 patients with primary hepatic carcinoma treated with whole body γ-knife from March 2014 to July 2015 underwent three-dimensional conformal radiotherapy planning,and dose volume histograms were used to evaluate the dose distribution of target volumes and normal tissue,and moreover conformity index (CI) and homogeneity index (HI) were analyzed.Results Between the two treatment plans,D98 and the mean dose Da of GTV were higher in whole body γ-knife plan than those in three-dimensional conformal radiotherapy plan.For PTV,the V95 of γ-knife and three-dimensional conformal radiotherapy were (95.05±0.02)％ and (90.00±0.03)％ (P=0.00) respectively.Target coverage of whole body γ-knife was better.For organ at risk,γ-knife showed better protection of normal tissue.Three-dimensional conformal radiotherapy showed better HI (GTV:0.11±0.15 vs 0.23±0.02,PTV:0.14±0.04 vs 0.21±0.03),while more normal liver tissue received excessive exposure.The whole body γ-knife increased dose of target volumes and decreased dose of normal tissue,while three-dimensional conformal radiotherapy showed better HI.Conclusion Compared with three-dimensional conformal radiotherapy,the whole body γ-knife shows advantage in dose distribution but HI of target volumes.For clinical using,appropriate treatment needs to be chosen according to the patients' actual situation.