宫颈癌直线加速器放疗时保卵巢对靶区和危及器官的影响

目的:探究宫颈癌直线加速器放疗时保卵巢对计划靶区和危及器官的剂量学影响。方法:随机选取16例保卵巢宫颈癌直线加速器放疗患者，基于XiO计划系统为每例患者设计7野均分调强计划，并通过归一使95%计划靶区剂量达到45 Gy。在除卵巢外其他优化参数相同的情况下，生成保卵巢组和不保卵巢组两组治疗计划，比较两组计划的靶区和危及器官的剂量学差异。结果:两组计划均满足临床要求。对于计划靶区，保卵巢组与不保卵巢组的适形度指数和均匀性指数分别为0.708±0.051、0.808±0.056（P<0.05）和0.135±0.023、0.087±0.012（P<0.05），保卵巢组适形度和均匀性显著下降。对于危及器官，保卵巢组小肠、膀胱、直肠和左股骨头的Dmax均大于不保卵巢组（P<0.05），而Dmean、V45、V40、V30、V20和V10无统计学差异（P>0.05）；保卵巢组脊髓Dmean、Dmax无统计学差异（P>0.05）。结论:保卵巢显著影响计划靶区的剂量分布，对危及器官影响甚微。

Effects of ovaries sparing on planning target volume and organs-at-risk during linearaccelerator radiotherapy for cervical cancer

Objective To explore the dosimetric effects of ovaries sparing in linear accelerator (LA) radiotherapy for cervicalcancer on planning target volume (PTV) and organs-at-risk (OAR). Methods Sixteen patients treated with ovaries-sparing LAradiotherapy for cervical cancer were randomly selected, and 7-field IMRT plans were designed for each patient based onXiO treatment planning system. The 95% of PTV receiving 45 Gy irradiation dose was achieved by normalization. With thesame optimization parameters except the treatment of ovaries, two groups of treatment plans, namely ovaries-sparing groupand no ovaries-sparing group, were generated, and the dosimetric differences of PTV and OAR between two groups werecompared. Results Both groups met the clinical requirements. The conformity index (CI) in ovaries-sparing group wassignificantly lower than that in no ovaries-sparing group (0.708±0.051 vs 0.808±0.056, P<0.05), and the homogeneity index(HI) in ovaries-sparing group was much higher (0.135±0.023 vs 0.087±0.012, P<0.05). For OAR, the Dmax of small intestine,bladder, rectum and left femoral head in ovaries-sparing group was higher than that in no ovaries-sparing group (P<0.05), butthere was no significant difference in Dmean, V45, V40, V30, V20 and V10 (P>0.05), and the Dmean and Dmax of spinal cord weresimilar in two groups, without statistical differences (P>0.05). Conclusion Ovaries sparing significantly affects the dosedistribution in PTV, but has trivial dosimetric effects on OAR.