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目的:比较研究宫颈癌常规调强放疗(conventional intensity-modulated radiotherapy,C-IMRT)与旋转容积调强放疗(volumetric intensity-modulated arc therapy,VMAT)计划对靶区及其周围危及器官受照剂量的差异。方法:随机选择2012-08-01-2013-05-31苏北人民医院收治的12例宫颈癌术后患者,进行CT模拟定位、靶区和危及器官的勾画,在同一CT图像上用治疗计划系统进行C-IMRT和VMAT计划设计,处方剂量均为CTV 50Gy,分25次,危及器官限量参考临床要求。在95%体积的PTV达到处方剂量的条件下,比较2种计划的剂量体积直方图,靶区、危及器官、靶区剂量适形度、剂量分布均匀性、机器跳数(monitor unit,MU)和治疗时间。对治疗计划结果采用配对t检验分析方法评价各指标的差异性。结果:VMAT计划与C-IMRT计划相比,膀胱的Dmean和V20两者差异无统计学意义,P>0.05;D50、V30和V40均明显降低(P<0.05),且直肠的D5和小肠的D1也明显降低(P<0.05),其他的危及器官的剂量学参数均没有明显降低。正常组织V10VMAT计划明显高于C-IMRT计划(P<0.05),而V30VMAT计划明显低于C-IMRT计划,P<0.05。VMAT计划相比于C-IMRT计划MU平均减少了50.7%;出束时间T减少了47.2%。结论:在宫颈癌术后放疗中,VMAT技术较C-IMRT技术有剂量学方面的优势,患者的治疗时间和机器跳数MU显著降低,在综合条件允许的情况下可推荐使用VMAT技术。
OBJECTIVE: To compare the effects of conventional intensity-modulated radiotherapy (C-IMRT) and volumetric intensity-modulated arc therapy (VMAT) on the target organ and its peri-implant dose difference. METHODS: Twelve patients with cervical cancer who underwent surgery at North Jiangsu Hospital from 2012-08-01-2013-05-31 were randomly selected. CT simulation, target area and organs at risk were performed. In the same CT images, treatment plans System C-IMRT and VMAT program design, prescription dose is CTV 50Gy, points 25 times, endangering organ limitation reference clinical requirements. The two planned dose-volume histograms, target area, endangered organs, target dose conformality, uniformity of dose distribution, monitor unit (MU) were compared under the prescribed dose of 95% And treatment time. The results of the treatment plan using paired t test analysis of the evaluation of the differences of the indicators. Results: Compared with the C-IMRT plan, there was no significant difference in Dmean and V20 between the VMAT and bladder (P> 0.05); D50, V30 and V40 were significantly lower (P <0.05) D1 was also significantly lower (P <0.05), other organs at risk did not significantly reduce the dose parameters. The normal tissue V10VMAT plan was significantly higher than the C-IMRT plan (P <0.05), while the V30VMAT plan was significantly lower than the C-IMRT plan, P <0.05. The VMAT plan has an average reduction of 50.7% compared to the C-IMRT plan MU; the beam-out time T has decreased by 47.2%. Conclusion: Compared with C-IMRT technique, the VMAT technique has the advantage of dosimetry in postoperative radiotherapy for cervical cancer. The treatment time and MU of machine hops are significantly reduced, and VMAT technology may be recommended when the overall conditions permit.