A beam-specific planning target volume (PTV) design for proton therapy to account for setup and range uncertainties.
A beam-specific planning target volume (PTV) design for proton therapy to account for setup and range uncertainties.
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DOI：
10.1016/j.ijrobp.2011.05.011
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发表时间：
2012-02-01
影响因子：
7
通讯作者：
Dong, Lei
中科院分区：
文献类型：
--
作者：
Park, Peter C;Zhu, X Ronald;Lee, Andrew K;Sahoo, Narayan;Melancon, Adam D;Zhang, Lifei;Dong, Lei
报告一种明确设计计划靶区（PTV）的方法，用于在异质介质中使用单场优化（SFO）进行被动散射质子治疗和扫描束质子治疗的治疗计划和评价。通过射线追踪和移动射线来计算质子束的束特异性PTV（bsPTV），以解释在存在设置误差或器官运动的情况下的组织未对准。由于基于CT的距离估计的不准确性范围的不确定性计算的近端和远端表面的目标在波束方向。然后基于局部异质性构建bsPTV。因此，bsPTV可以直接用作计划目标，就像它在光子治疗中一样。为了测试bsPTV的鲁棒性，我们在虚拟体模中生成了单场质子计划。引入了有意设置和范围误差。比较了基于bsPTV和常规PTV设计的计划在各种模拟条件下对临床靶区（CTV）的剂量覆盖。使用bsPTV设计的模拟治疗在维持CTV的剂量覆盖方面明显优于使用传统PTV的计划。在传统的PTV计划中，在存在设置误差、内部运动和距离不确定性的情况下，对CTV的最小覆盖率从99%下降到67%。然而，使用bsPTV的计划显示目标覆盖率从99%降至94%。光子治疗中使用的传统的基于几何的PTV概念对于质子治疗不起作用。我们研究和验证了一个特定的束流PTV方法设计和评估质子计划。
To report a method for explicitly designing a planning target volume (PTV) for treatment planning and evaluation in heterogeneous media for passively scattered proton therapy and scanning beam proton therapy using single-field optimization (SFO). A beam-specific PTV (bsPTV) for proton beams was derived by ray-tracing and shifting ray lines to account for tissue misalignment in the presence of setup error or organ motion. Range uncertainties due to inaccuracies in CT-based range estimation were calculated for proximal and distal surfaces of the target in the beam direction. The bsPTV was then constructed based on local heterogeneity. The bsPTV thus can be used directly as a planning target as if it were in photon therapy. To test the robustness of the bsPTV, we generated a single-field proton plan in a virtual phantom. Intentional setup and range errors were introduced. Dose coverage to the clinical target volume (CTV) under various simulation conditions was compared between plans designed based on the bsPTV and a conventional PTV. The simulated treatment using the bsPTV design performed significantly better than the plan using the conventional PTV in maintaining dose coverage to the CTV. With conventional PTV plans, the minimum coverage to the CTV dropped from 99% to 67% in the presence of setup error, internal motion and range uncertainty. However, plans using the bsPTV showed minimal drop of target coverage from 99% to 94%. The conventional geometry-based PTV concept used in photon therapy does not work well for proton therapy. We investigated and validated a beam-specific PTV method for designing and evaluating proton plans.