脑胶质瘤术后VMAT与IMRT放疗技术间比较

摘要

Objective: This planning study compares IMRT with VMAT for discussing the dosimetric characteristics of VMAT in the intracranial tumor radiation therapy. Materials and Methods: Totally 10 treated patients of intracranial tumors were re-planned to 60 Gy in 30 fractions with VMAT and IMRT using Monaco treatment planning system.We compared DVH, confor-mal index, homogeneity index , treatment time, monitor units, and the dose of organs at risk between the two groups. Results: There was equivalent CI and HI {P >0.05), VMAT significantly reduced treatment time and monitor units (P＜0.05). To the the dose of organs at risk, the mean of brainstem and optic chiasm were similar (P>0.05), while the men of optic nerve, retina, lens, and the normal brain ,VMAT significantly lower than the IMRT group (P＜0.05). Conclusions: Compared with IMRT, VMAT achieves better OAR sparing while using fewer monitor units and less time to treat intracranial tumor.%目的:比较脑胶质瘤术后容积旋转调强(Volumetric Modulated Arc Therapy,VMAT)计划与静态调强(Intensity Modulated Radiation Therapy,IMRT)计划,讨论VMAT的剂量学特性,分析VMAT在脑胶质瘤术后放射治疗中的应用.材料与方法:选取10例颅内肿瘤患者,采用Monaco治疗计划系统,分别制作VMAT计划与IMRT计划,处方剂量全部为PTV:60 Gy/30f.比较两组计划的剂量分布图、DVH图、适形度指数(CI)、均匀指数(HI)、治疗时间、治疗跳数(MU)、危及器官受量.结果:两组计划靶区剂量分布及适形度均较好,CI、HI数相近(P＞0.05),但VMAT组的治疗时间和MU均优于IMRT组(P＜0.05).在危及器官受量方面,两组计划的脑干与视交叉的平均剂量相近(P＞0.05),而视神经、视网膜、晶体和周围正常脑组织的平均剂量,VMAT组明显低于IMRT组(P＜0.05).结论:在脑胶质瘤术后的放射治疗中,VMAT与IMRT的靶区剂量分布相近.VMAT的优势在于大大缩小缩短治疗时间、减少MU,同时减少了部分危及器官受量.