A model to accumulate fractionated dose in a deforming organ
A model to accumulate fractionated dose in a deforming organ
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DOI：
10.1016/s0360-3016(99)00007-3
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发表时间：
1999-06-01
影响因子：
7
通讯作者：
Wong, JW
中科院分区：
文献类型：
--
作者：
Yan, D;Jaffray, DA;Wong, JW
目的：内部器官运动的测量表明，在整个放射治疗过程中每天都存在器官变形。然而，构建输送到器官体积的最终剂量的方法仍然是一个艰巨的挑战。在这项研究中，介绍了一种量化内部器官运动的模型和一种在变形器官中构建累积剂量的方法。方法和材料：使用弹性体的生物力学模型来量化放射治疗过程中患者器官的运动。感兴趣器官中体积元素的治疗间位移是通过应用具有边界条件的有限元方法来计算的，该边界条件是从多次日常计算机断层扫描 (CT) 测量中获得的。因此，通过还结合每日设置误差的测量，可以通过跟踪器官中体积元件的位置来累积递送至变形器官的每日剂量。此外，还可以在治疗实施的早期阶段使用每日测量来预测患者特定器官运动的分布，然后可以估计器官中的累积剂量分布。只要有新的测量结果可用，该剂量分布就会更新，并用于重新优化正在进行的治疗。结果：实施了在每日变形器官中累积剂量的综合过程。在此过程中，治疗间器官运动和设置误差被系统量化，并纳入累积剂量的计算中。应用前列腺治疗中直肠壁运动的示例来测试模型。计算了直肠壁中体积元素的位移以及由此产生的剂量。结论：本研究旨在提供一个系统框架，将日常患者特定器官运动和设置误差纳入感兴趣器官累积剂量分布的重建中。感兴趣器官中的真实剂量分布给出了真实的剂量-体积关系，并且可能在评估人体器官的剂量反应中发挥重要作用。治疗过程中的剂量重建也可以作为在线优化个体治疗计划的重要反馈。 (C) 1999 爱思唯尔科学公司。
Purpose: Measurements of internal organ motion have demonstrated that daily organ deformation exists throughout the course of radiation treatment. However, a method of constructing the resultant dose delivered to the organ volume remains a difficult challenge. In this study, a model to quantify internal organ motion and a method to construct a cumulative dose in a deforming organ are introduced.Methods and Materials: A biomechanical model of an elastic body is used to quantify patient organ motion in the process of radiation therapy. Intertreatment displacements of volume elements in an organ of interest is calculated by applying an finite element method with boundary conditions, obtained from multiple daily computed tomography (CT) measurements. Therefore, by incorporating also the measurements of daily setup error, daily dose delivered to a deforming organ can be accumulated by tracking the position of volume elements in the organ. Furthermore, distribution of patient-specific organ motion is also predicted during the early phase of treatment delivery using the daily measurements, and the cumulative dose distribution in the organ can then be estimated. This dose distribution will be updated whenever a new measurement becomes available, and used to reoptimize the ongoing treatment.Results: An integrated process to accumulate dosage in a daily deforming organ was implemented. In this process, intertreatment organ motion and setup error were systematically quantified, and incorporated in the calculation of the cumulative dose. An example of the rectal wall motion in a prostate treatment was applied to test the model. The displacements of volume elements in the rectal wall, as well as the resultant doses, were calculated.Conclusion: This study is intended to provide a systematic framework to incorporate daily patient-specific organ motion and setup error in the reconstruction of the cumulative dose distribution in an organ of interest. The realistic dose distribution in an organ of interest gives the true dose-volume relationship, and may play an important role in the evaluation of the dose response of human organs. Dose reconstruction during the course of treatment delivery can also be used as an important feedback for the online optimization of individual treatment plans. (C) 1999 Elsevier Science Inc.