Optimization of internal margin to account for dosimetric effects of respiratory motion
Optimization of internal margin to account for dosimetric effects of respiratory motion
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DOI：
10.1016/j.ijrobp.2007.12.025
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发表时间：
2008-04-01
影响因子：
7
通讯作者：
Brinkmann, Debra H.
中科院分区：
文献类型：
--
作者：
Mutaf, Yildirim D.;Brinkmann, Debra H.
目的：使用内边缘来解释靶体积的呼吸运动是移动的肿瘤放射治疗中的常用策略。尽管这种扩张对于肿瘤覆盖是有效的，但也有增加对附近健康器官的毒性的风险，因此需要仔细选择适当的边缘。在这项研究中，我们证明了优化的内部边缘用于占呼吸motion.Methods和材料：三维适形治疗计划的幻影球形目标体积以及11例患者的临床治疗计划进行了回顾性评价，最佳的内部边缘选择。对所有病例进行了基于软件的呼吸运动模拟。此外，治疗设置的不确定性和相应的利润率的相互作用进行了研究，在幻影study.Results：最佳的内部利润率在幻影和患者的研究被发现是大大小于由于呼吸的实际目标位移。还观察到最佳内部裕度近似独立于设置裕度。此外，没有统计学意义上的依赖目标的大小和形状，观察组中的11 patients.Conclusions：这些研究结果提出了显着的影响治疗计划的移动的目标，如发现在肺和上腹部的肿瘤。我们的结论是，内部边缘的全运动幅度过于保守，内部边缘的优化提供了改善的备用附近器官的风险，而不牺牲剂量覆盖的目标。(c)2008年爱思唯尔公司
Purpose: Use of internal margins to account for respiratory motion of the target volumes is a common strategy in radiotherapy of mobile tumors. Although efficient for tumor coverage, this expansion also risks increased toxicity to nearby healthy organs and therefore requires a careful selection of appropriate margins. In this study, we demonstrate an optimization of the internal margin used to account for respiration motion.Methods and Materials: Three-dimensional conformal treatment plans for phantom spherical target volumes as well as clinical treatment plans of 11 patients were evaluated retrospectively for optimum internal margin selection. A software-based simulation of respiration motion was performed for all cases. Moreover, the interplay with treatment setup uncertainties and corresponding margins was investigated in the phantom study.Results: Optimum internal margins in both phantom and patient studies were found to be substantially smaller than the actual target displacement due to respiration. The optimal internal margin was also observed to be approximately independent of the setup margins. Furthermore, no statistically significant dependence on target size and shape was observed in the group of 11 patients.Conclusions: These findings present significant implications for treatment planning of mobile targets, such as tumors found in the lung and upper abdomen. We conclude that the full motion amplitude for the internal margin is overly conservative, and optimization of the internal margin provides improved sparing of nearby organs at risk without sacrificing dosimetric coverage for the target. (c) 2008 Elsevier Inc.