摘要
目的:探讨容积调强技术在全脑放射治疗中对海马区保护的可行性,对比分析共面旋转调强计划与非共面旋转调强计划在海马区保护中的优缺点。方法:选取10例需进行全脑放射治疗的脑转移患者,分别对其进行共面旋转调强和非共面旋转调强的计划设计,对两组计划的机器跳数、靶区的均匀性指数和适形度指数以及危及器官的受量进行比较。结果:两组计划均能降低海马区的剂量,海马区D_(mean)分别为9.7、9.6 Gy。两组计划的海马区D_(100%)、D_(mean)、D_(40%)、D_(max)的均值相差不大;两组计划的靶区均匀性指数和适形度指数在统计学上均无差异。非共面计划的机器跳数比共面计划的大。两组计划的危及器官受量均在临床要求的范围内。结论:在海马保护的全脑放射治疗中,共面旋转调强计划与非共面旋转调强计划均可达到临床要求,且差异不明显。
Objective To discuss the feasible of volumetric modulated arc therapy(VMAT) for the protection of the hippocampus in whole brain radiotherapy(WBRT), and investigate the advantages and disadvantages of coplanar and non-coplanar VMAT plans for hippocampal-sparing WBRT. Methods Ten patients receiving WBRT for brain metastases were enrolled in this study.Two different plans, namely coplanar and non-coplanar VMAT plans, were designed for each patient. The monitor unit, the homogeneity index and conformity index of target areas, and the organs-at-risk dose were compared between two plans. Results Both the two plans reduced the dose of the hippocampus, and the D_(mean) of the hippocampus in coplanar and non-coplanar VMAT plans were 9.7 and 9.6 Gy, respectively. Moreover, the mean values of the D_(100%), D_(mean), D_(40%), and Dmaxof the hippocampus were similar in the two plans, and no statistical difference was found in the homogeneity index and conformity index of target areas.However, the monitor unit of non-coplanar VMAT plan was larger than that of coplanar VMAT plan. The organs-at-risk doses in the two plans met the clinical requirements. Conclusion Both coplanar and non-coplanar VMAT plans for hippocampal-sparing WBRT satisfy the clinical requirements, and the difference between the two plans is trivial.
引文
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