非共面IMRT在宫颈癌放疗计划中保护卵巢的可行性探讨

目的:探讨非共面IMRT在宫颈癌放疗计划中保护卵巢的可行性。方法:选取17例保卵巢宫颈癌放疗病例，按统一标准分别设计两组IMRT计划:共面IMRT保卵巢组(A组)和非共面IMRT保卵巢组（B组）；收集两组计划评估参数，并验证两组计划γ通过率，并进行统计学分析。结果:两组计划均满足临床要求。B组的卵巢最大受量小于A组（P＜0.05）。对于计划靶区，B组计划的适形指数、均匀指数优于A组计划（P＜0.05），A组D5高于B组（P＜0.05），B组D95高于A组（P＜0.05）。对于危及器官，A组在膀胱的V40、直肠的Dmean、小肠的Dmax、左侧股骨头的V20大于B组（P＜0.05）。A组和B组在膀胱的V20、V30、Dmean,直肠的V30、V40，小肠的V40，右侧股骨头的V10、V20、V30，左侧股骨头的V10、V30和骨髓的Dmax上均无明显差异（P＞0.05）。A组的总跳数小于B组（P＜0.05）；在3%/2 mm,低剂量阈值10%的标准下，A组γ通过率高于B组（P＜0.05）。结论:两种计划均能实现对卵巢的保护，非共面IMRT计划表现更佳，靶区剂量分布更优，对危及器官影响更小。

Feasibility of ovarian sparing by non-coplanar IMRT radiotherapy for cervical cancer

Objective:To study the feasibility of ovarian sparing by non-coplanar IMRT radiotherapy for cervical cancer.Methods:A total of 17 ovarian sparing patients with cervical cancer were selected.The IMRT plans for two groups were designed separately according to unified criteria,including the coplanar IMRT plans for ovarian sparing (group A),and non-coplanar IMRT plans for ovarian sparing(group B).Plan parameters of two groups were collected，and the γ passing rate was verified.Statistical analysis studies were performed.Results:All the plans for two groups met clinical requirements.The maximum dose of ovarian in group B was lower than group A(P＜0.05).For planing target volume(PTV),the conformity index(CI) and the homogeneity index(HI) of group B were better than group A(P＜0.05).The D5 of group A was higher than group B(P＜0.05),and the D95 of group B was higher than group A(P＜0.05).For organ at risk(OAR),V40 of bladder,Dmean of rectum,Dmax of small intestine,and V20 of left femoral head in group A were higher than group B(P＜0.05).There were no significant differences in V20,V30,Dmean of bladder,V30,V40 of rectum,V40 of small intestine,V10,V20,V30 of right femoral head，V10,V30 of left femoral head and Dmax of bone marrow between group A and group B(P＞0.05).The number of MU for group B was higher than group A.With the criterion of 3%/2 mm and threshold of 10%,the γ passing rate of the group A was higher than group B (P＜0.05).Conclusion:Both group A and group B could achieve ovarian sparing,but the non-coplanar IMRT plan performs better,with better dose distribution in PTV and less impact on organs at risk.