宫颈癌术后容积旋转调强与三维适形调强放疗技术的剂量学差异

目的:比较宫颈癌术后放疗中旋转调强放射治疗(VMAT)与三维适形调强放疗(IMRT)的剂量学差异。方法:随机选取 20 例宫颈癌术后患者，在Eclipse计划系统中分别对每例患者进行容积旋转调强和7野固定野调强放疗(7IMRT)计划设计，比较两种技术的靶区的适形指数、危及器官的受照剂量、机器跳数和治疗时间的差异。结果:VMAT 技术靶区的平均剂量为52.05 Gy，高于 7IMRT技术的51.46 Gy(P＜0.05)，靶区的均匀性指数与适形度优于7IMRT 技术，机器跳数和治疗时间 VMAT 比7IMRT明显减少，差异有统计学意义。小肠、膀胱的V30、V50 、Dmean较7IMRT降低，差异有统计学意义；但直肠和股骨头的保护性上，两种放疗技术差异无统计学意义。结论:VMAT技术较IMRT技术可得到更好的靶区剂量分布，危及器官也能得到更好的保护，治疗时间明显缩短，值得在临床中开展应用。

Dosimetry difference between postoperative volumetric modulated arc therapy and intensity modulated radiotherapy for cervical cancer

Objective:To compare the dosimetric difference between volumetric modulated arc therapy(VMAT)and 7 field fixed field intensity modulated radiotherapy(7IMRT)in postoperative radiotherapy of cervical cancer.Methods:Twenty patients with cervical cancer were randomly selected design of volumetric modulated arc therapy and 7 field fixed field intensity modulated radiotherapy for each patient in Eclipse planning system.The conformal index of the target region between the two techniques was compared.The difference of exposure dose,machine hop number and treatment time between the two techniques was also compared.Results:The average dose of VMAT target area was 52.05 Gy,higher than 51.46 Gy for 7IMRT.The uniformity index and conformal degree of the target region were better than that of 7IMRT.The number of machine hops and treatment time VMAT was significantly lower than that of 7IMRT.The difference was statistically significant.The V 30 , V 50 and D mean of small intestine and bladder were lower than that of 7IMRT( P <0.05).However,there was no significant difference between the two radiotherapy techniques in the protection of rectum and femoral head. Conclusion: The target dose distribution of VMAT is better than that of 7IMRT.Endangering organs can also be better protected,and the treatment time is significantly shorter.It is worthy of clinical application.