容积旋转调强与固定野动态调强在宫颈癌术后放疗的剂量学比较

Dosimetric comparison and clinical application of RapidArc and intensity-modulated radiotherapy for postoperative radiotherapy of cervical cancer

目的比较容积旋转调强（RapidArc）与固定野动态调强（IMRT）两种宫颈癌术后放疗的剂量学参数及急性不良反应发生率，为临床治疗技术的选择提供参考依据。方法选取35例宫颈癌术后盆腔预防放疗患者，其中，17例接受RapidArc，18例接受IMRT，处方剂量50Gy，共25次。比较两组治疗计划的剂量一体积直方图（DVH）、靶区剂量适形度、均匀性、靶区及危及器官的剂量、机器跳数及治疗时间；对比两组患者治疗期间的急性肠道及膀胱反应发生率。结果与IMRT相比，RapidArc靶区剂量适形度较高（t=3．13，P〈0．05），但均匀性略低（t=-4．25，P〈0．05）；RapidArc计划中股骨头V20、U30均低于IMRT（t=2．56、2．34，P〈0．05）；RapidArc计划机器跳数减少了52．1％，治疗所需时间缩短了46．8％。两组患者肠道、膀胱急性不良反应发生率相近。结论对于宫颈癌术后盆腔预防放疗患者，采用RapidArc或IMRT技术均可达到靶区的剂量要求及保护危及器官的目的。RapidArc计划靶区剂量学参数、急性不良反应发生率与IMRT计划比较未见明显优势，但机器跳数与出束时间明显优于IMRT计划，实现了治疗效率的大幅提高。

Objective To compare the planning quality and acute toxicity between RapidArc and fixed gantry angle dynamic intensity modulated radiotherapy （IMRT） in the postoperative radiotherapy for cervical cancer patients. Methods All 35 patients with cervical cancer who had received postoperative radiotherapy were studied, including 17 patients with RapidArc and 18 patients with IMRT. All plans were prescribed 50 Gy in 25 fractions. The dose-volume histogram data, the conformity index and homogeneity index of the targets, the monitor units （MUs） and delivery time were compared. During the treatment, the incidence of acute intestinal and bladder side effects were also compared. Results Compared to IMRT, the conformity index of RapidArc was better（ t = 3.13 ,P 〈 0.05 ） , but the homogeneity index was slightly worse （ t = - 4. 25,P 〈 O. 05 ）. The V20 and V3o of femoral head planned by RapidAre was significantly lower than that by IMRT（t = 2.56, 2.34,P 〈 0.05）. The mean MU for RapidAre was reduced by 52. 1% compared with IMRT. The mean treatment time for RapidArc was decreased by 46.8% compared with IMRT. There was no difference in the incidence of acute intestinal and bladder toxicity between the two groups. Conclusion For patients with cervical cancer who need prophylactic postoperative radiotherapy, both RapidArc and IMRT plan can achieve equal target coverage and organs at risk（OAR） sparing. There is no significant difference in dosimetric parameters and acute toxicity between the two groups. Compared with IMRT, RapidArc plan has fewer MUs and less treatment time and significantly improves the treatment efficiency.