Patient geometry-driven information retrieval for IMRT treatment plan quality control
Patient geometry-driven information retrieval for IMRT treatment plan quality control
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DOI：
10.1118/1.3253464
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发表时间：
2009-12-01
期刊：
影响因子：
3.8
通讯作者：
McNutt, Todd
中科院分区：
文献类型：
--
作者：
Wu, Binbin;Ricchetti, Francesco;McNutt, Todd
目的：调强放射治疗（IMRT）治疗计划的质量取决于计划者的经验水平和计划者在制定计划上投入的时间。患者往往无意中接受计划时，进一步节省器官的风险（OAR）是可能的。作者提出了一种方法的IMRT治疗计划的质量控制，帮助规划师评估剂量的OARs后完成一个新的planne.Methods：它是通过比较的几何配置的OARs和目标的一个新的病人与以前的病人，其计划是在数据库中维护。他们引入了形状关系描述符的概念，特别是重叠体积直方图（OVH）来描述OAR相对于目标的空间配置。OVH提供了一种通过比较患者之间的相对空间配置来推断OAR的可能DVH的方法。建立既往患者数据库，作为外部参考。在新计划结束时，计划者搜索数据库，并通过比较新患者与先前患者的OAR-目标几何关系来识别相关患者。从数据库中检索这些相关患者的治疗计划，并指导规划者确定是否在新planne.Results中提供给OARs的较低剂量是可行的：初步评估是有希望的。在这项评估中，他们将分析应用于32名既往头颈部患者的腮腺DVH，这些患者的计划保存在数据库中。针对其他63个腮腺询问每个腮腺，以确定是否可能降低剂量。标记了承诺D-50（DVH剂量为50%体积）降低最大的17个腮腺。这17个腮腺来自13名患者。该方法还表明，13名患者的其他9个腮腺的剂量不能减少，因此将其作为对照纳入重新计划过程。对这26个腮腺进行了重新规划，以减少D-50。重新计划后，17个标记腮腺和9个未标记腮腺的D-50平均减少分别为6.6和1.9戈伊。这些结果表明，质量控制方法不仅准确识别了需要降低剂量的腮腺，而且还准确识别了剂量降低幅度很小的腮腺。最初，17个标记腮腺中的11个不符合放射治疗肿瘤学组的V（30戈伊）<50%的保留目标。重新规划后，他们减少到三个。此外，通过使用成对Wilcoxon p检验，将原始计划的PTV覆盖率和OAR保留率与replans的PTV覆盖率和OAR保留率进行比较。的统计比较表明，重新规划既不损害PTV的覆盖范围，也不OAR sparing.Conclusions：这种方法提供了一个有效的质量控制机制，用于评估的DVH的OARs。采用这种方法将提高当前IMRT计划的质量，提供更好的治疗计划一致性。(C)2009年美国医学物理学家协会。[DOI：10.1118/1.3253464]
Purpose: Intensity modulated radiation therapy (IMRT) treatment plan quality depends on the planner's level of experience and the amount of time the planner invests in developing the plan. Planners often unwittingly accept plans when further sparing of the organs at risk (OARs) is possible. The authors propose a method of IMRT treatment plan quality control that helps planners to evaluate the doses of the OARs upon completion of a new plan.Methods: It is achieved by comparing the geometric configurations of the OARs and targets of a new patient with those of prior patients, whose plans are maintained in a database. They introduce the concept of a shape relationship descriptor and, specifically, the overlap volume histogram (OVH) to describe the spatial configuration of an OAR with respect to a target. The OVH provides a way to infer the likely DVHs of the OARs by comparing the relative spatial configurations between patients. A database of prior patients is built to serve as an external reference. At the conclusion of a new plan, planners search through the database and identify related patients by comparing the OAR-target geometric relationships of the new patient with those of prior patients. The treatment plans of these related patients are retrieved from the database and guide planners in determining whether lower doses delivered to the OARs in the new plan are feasible.Results: Preliminary evaluation is promising. In this evaluation, they applied the analysis to the parotid DVHs of 32 prior head-and-neck patients, whose plans are maintained in a database. Each parotid was queried against the other 63 parotids to determine whether a lower dose was possible. The 17 parotids that promised the greatest reduction in D-50 (DVH dose at 50% volume) were flagged. These 17 parotids came from 13 patients. The method also indicated that the doses of the other nine parotids of the 13 patients could not be reduced, so they were included in the replanning process as controls. Replanning with an effort to reduce D-50 was conducted on these 26 parotids. After replanning, the average reductions for D-50 of the 17 flagged parotids and nine unflagged parotids were 6.6 and 1.9 Gy, respectively. These results demonstrate that the quality control method has accurately identified not only the parotids that require dose reductions but also those for which dose reductions are marginal. Originally, 11 of out the 17 flagged parotids did not meet the Radiation Therapy Oncology Group sparing goal of V(30 Gy) < 50%. Replanning reduced them to three. Additionally, PTV coverage and OAR sparing of the original plans were compared to those of the replans by using pairwise Wilcoxon p test. The statistical comparisons show that replanning compromised neither PTV coverage nor OAR sparing.Conclusions: This method provides an effective quality control mechanism for evaluating the DVHs of the OARs. Adoption of such a method will advance the quality of current IMRT planning, providing better treatment plan consistency. (C) 2009 American Association of Physicists in Medicine. [DOI: 10.1118/1.3253464]