基于改进非共面容积旋转调强海马保护全脑放疗的剂量学研究-《中国医学物理学杂志》

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Title:: Dosimetric study on improved non-coplanar volumetric modulated arc therapy for hippocampal avoidance whole-brain radiotherapy

文章编号:: 1005-202X（2021）05-0529-05

作者:: 余枭; 闫冰; 刘磊; 李骁扬; 沈建军; 吴爱东

Author(s):: YU Xiao; YAN Bing; LIU Lei; LI Xiaoyang; SHEN Jianjun; WU Aidong; Department of Radiation Oncology, the First Affiliated Hospital of University of Science and Technology of China, Hefei 230001, China

关键词:: 中国科学技术大学附属第一医院放疗科; 安徽合肥 230001

Keywords:: hippocampus whole-brain radiotherapy volumetric modulated arc therapy non-coplanar coplanar

分类号:: R811.1；R815.6

DOI:: DOI:10.3969/j.issn.1005-202X.2021.05.001

文献标志码:: A

摘要:: 目的：对已有的非共面容积旋转调强（VMAT）海马保护全脑放疗（HA-WBRT）方法进行改进，比较改进的非共面VMAT计划与非共面、共面VMAT计划在HA-WBRT中的剂量学差异。方法：选取15例颅外肿瘤脑转移需行WBRT的患者，分别对每例患者设计改进非共面、非共面和共面VMAT计划，并对3种计划的靶区、危及器官剂量以及加速器MU值和治疗时间进行比较。结果：改进非共面VMAT计划与非共面、共面VMAT计划相比，改进非共面VMAT计划靶区适形性和剂量梯度的差异无统计学意义（P>0.05），但靶区剂量均匀性略差于另外两种计划。在海马体组织Dmax、Dmin、Dmean 3项剂量参数上，改进非共面计划可分别控制在约14.37、8.40和10.80 Gy，显著小于非共面和共面计划相应值（P<0.05）；其它危及器官如晶体、视神经等剂量均控制在临床安全剂量范围内，各计划之间差异不显著；改进非共面计划MU值和治疗时间均大于非共面计划和共面计划，差异有统计学意义（P<0.05）。结论：相较于非共面和共面VMAT计划，本研究改进的非共面VMAT方法在HA-WBRT中能更进一步降低海马组织的受照剂量，为临床实施HA-WBRT时提供一种切实可行的治疗方案。

Abstract:: Objective To improve the non-coplanar volumetric modulated arc therapy (VMAT) for hippocampal avoidance whole-brain radiotherapy (HA-WBRT), and to compare dosimetric differences among improved non-coplanar VMAT, non-coplanar VMAT and coplanar VMAT for HA-WBRT. Methods Fifteen patients scheduled for WBRT for brain metastasis from extracranial tumors were enrolled in the study, and 3 different kinds of plans, namely improved non-coplanar VMAT, non-coplanar VMAT and coplanar VMAT plans, were designed for each patient. The doses delivered to target areas and organs-at-risk, monitor unit and treatment time were compared among 3 different kinds of plans. Results There were no statistical differences among 3 different kinds of plans in conformity index and gradient index (P>0.05), but improved non-coplanar VMAT plan had a higher homogeneity index than the other two kinds of plans. The Dmax, Dmin and Dmean of hippocampus in improved non-coplanar VMAT plans could be limited to 14.37, 8.40 and 10.80 Gy, respectively, which were significantly lower than those in non-coplanar VMAT plans and coplanar plans (P<0.05). The doses delivered to other organs-at-risk, such as lens and optic nerves, were within the range of clinical safe dose, and no statistical significance was found among different plans. The monitor unit and treatment time of improved non-coplanar VMAT plans were both greater than those of non-coplanar VMAT plans and coplanar VMAT plans, with statistical differences (P<0.05). Conclusion Compared with non-coplanar VMAT and coplanar VMAT, improved non-coplanar VMAT for HA-WBRT can further reduce the dose delivered to hippocampus, providing a practicable treatment strategy for the clinical application of HA-WBRT.

《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]

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