术前宫颈癌容积旋转调强与固定野动态调强技术剂量对比

目的:比较容积旋转调强（VMAT）和固定野动态调强放疗（DIMRT）技术在术前宫颈癌放疗中的剂量学差别。 方法:选取10例接受放疗的术前宫颈癌患者，勾画靶区，用Eclipse 11.0计划系统设计双弧VMAT计划和5野DIMRT计划，比较两者靶区的适形度指数（CI）和均匀性指数（HI）、危及器官的剂量学差别、加速器跳数和照射时间。 结果:双弧VMAT计划与5野DIMRT计划的CI（0.78±0.05，0.84±0.03; P>0.05）和HI（0.05±0.00, 0.05±0.00; P>0.05）统计学无显著性差异，膀胱的V40、V45、V50和小肠的V20、股骨头、骨盆剂量有显著性差异之外，其它指标未有显著性差异。 结论:VMAT和DIMRT技术两者均能很好达到临床剂量学的要求，但在保护正常器官方面，VMAT比DIMRT技术更优或相当，VMAT技术在减少加速器跳数和照射时间方面优势明显。

Dose comparison of preoperative volumetric modulated arc therapy and dynamic intensity-modulated radiotherapy for cervical cancer

Abstract: Objective To compare the dosimetric differences between volumetric modulated arc therapy (VMAT) and dynamic intensity-modulated radiotherapy (DIMRT) in preoperative radiotherapy for cervical cancer. Methods Ten patients receiving preoperative radiotherapy for cervical cancer were selected. After target areas were delineated, double-arc VMAT plan and 5-field DIMRT plan were designed with Eclipse 11.0 planning system. The conformity index and homogeneity index of target areas, dosimetric differences of organs-at-risk, monitor units and treatment time were compared. Results The conformity index and homogeneity index were similar in double-arc VMAT plan and 5-field DIMRT plan (0.78±0.05 vs 0.84±0.03, P>0.05; 0.05±0.00 vs 0.05±0.00, P>0.05). No significant differences were found in dosimetric indexes, except the V40, V45, V50 of bladder, the V20 of small intestine, the dose of femoral head and pelvis. Conclusion Both VMAT and DIMRT can meet the requirements of clinical dosimetry. VMAT is equivalent or superior to DIMRT in protecting normal organs. Moreover, VMAT technology has significant advantages in reducing monitor units and shortening treatment time.