宫颈癌术后快速旋转调强放疗和三维适形放疗计划的对比研究

摘要

Objective To compare the differences of dose distribution in clinical target volume and organ at risk (OAR) between volumetric-modulated arc therapy(RapidArc) and conventional three-dimensional conformal radiotherapy (3D-CRT) in the radiotherapy of postoperative cervical cancer.Methods Ten postoperative patients with cervical cancer were chosen randomly.The next steps were CT scan,PTV and OAR contouring.The RapidArc plan and 3D-CRT plan were performed for each patient with the prescribed dose 50Gy,respectively.Homogeneity index (HI),conformity index (CI),maximum dose (PTVmax),minimum dose (PTVmin),mean dose(PTVmean) of PTV and irradiated volume of OARs were calculated and the results were compared.Results Conformity index (CI) of PTV and PTV Dmean in RapidArc plan were better than those in 3D-CRT plan with statistically significant difference (P ＜ 0.05).Compared with 3D-CRT plans,V20 of the left and right femoral head,V50 of the bladder and V40,V50 of rectumin RapidArc plans all reduced and the differences were statistically significant (P ＜ 0.05).While there were no significant difference on the PTV Dmax,PTV Dmin,HI and OARs(V10,V20,V30,V40,V50 of the small bowel,V10,V20,V30 of the rectum,V1o,V20,V30,V40 of the bladder,V10,V30,V40,V50 of the left and right femoral head) between 3D-CRT and RapidArc group (P ＞ 0.05).Conclusion RapidArc plans are better than 3D-CRT plans in CI of PTV and PTV Dmean in the radiotherapy of postoperative cervical cancer.Meanwhile,compared with 3D-CRT plans,there are more advantages in sparing the OAR in RapidArc plans.%目的 探讨宫颈癌术后快速旋转调强放疗(RapidArc)和三维适形放疗(3D-CRT)计划靶区及其周围危及器官(0AR)受照剂量的差异.方法 随机选择10例宫颈癌术后患者,进行CT扫描、靶区(PTV)和OAR的勾画,处方剂量50Gy.分别进行RapidArc和3D-CRT计划设计,计算并比较两种计划的PTV剂量均匀度指数(HI)、适形度指数(CI)、最大受照剂量(PTV Dmax)、最小受照剂量(PTV Dmin)、平均受照剂量(PTV Dmean)和OAR受照体积.结果 RapidArc计划的CI及PTV Dmean均优于3D-CRT计划；RapidArc计划对OAR(膀胱V50,直肠V40、V50,左、右股骨头V20)的保护优于3D-CRT计划(P＜0.05).两种计划的PTV Dmax、PTV Dmin、HI和OAR受照体积(小肠V10、V20、V30、V40、V50,直肠V10、V20、V30,膀胱V10、V20、V30、V40,左、右股骨头V10、V30、V40、V50)的差异均无统计学意义(P＞0.05).结论 宫颈癌术后辅助放疗中,RapidArc计划在靶区CI和PTV Dmean方面均优于3D-CRT,同时RapidArc计划在正常组织保护上也有一定的优势.