Optimal Allocation of Proton Therapy Slots in Combined Proton-Photon Radiation Therapy
Optimal Allocation of Proton Therapy Slots in Combined Proton-Photon Radiation Therapy
复制标题
DOI：
10.1016/j.ijrobp.2021.03.054
复制
发表时间：
2021-08-01
影响因子：
7
通讯作者：
Unkelbach, Jan
中科院分区：
文献类型：
--
作者：
Loizeau, Nicolas;Fabiano, Silvia;Unkelbach, Jan
目的：质子治疗是一种有限的资源，并不是所有患者都可以从中受益，我们研究了质子-光子联合治疗，其中一些部分用质子输送，其余部分用光子输送，作为一种在人群水平上最大限度地利用有限质子治疗资源的方法。方法和材料：为了量化质子和光子之间正常组织并发症概率（NTCP）的差异，我们考虑了一组45例头颈部癌症患者，这些患者先前已制定了调强放射治疗和调强质子治疗计划，并结合荷兰质子患者选择中考虑的口干症和吞咽障碍的NTCP模型。假设质子槽的可用性有限，我们开发了在质子-光子联合治疗中最佳分配质子分数的方法，以最小化总体水平上的平均NTCP。将联合治疗与患者选择策略进行比较，其中患者被分配到单模态质子或光子治疗。结果如下：由于NTCP函数的非线性，与患者选择相比，质子-光子联合治疗有一个好处;也就是说，初始质子分数是最有益的，而当达到NTCP曲线的平坦部分时，额外的质子分数的好处会减少。对于所考虑的患者队列和NTCP模型，该效应较小，但如果更好地了解剂量-反应关系，则该效应可能更大。此外，当质子插槽有限时，患者选择方法面临着在留下插槽未使用和阻止插槽用于可能具有更大益处的未来患者之间的权衡。结合质子-光子治疗与灵活的质子槽分配提供了一种方法，使所有可用的资源的最佳利用。结论：质子-光子联合治疗可以更好地利用有限的质子治疗资源。患者选择方案的受益取决于NTCP模型以及质子和光子之间的剂量差异。(c)2021爱思唯尔公司All rights reserved.
Purpose: Proton therapy is a limited resource that is not available to all patients who may benefit from it. We investigated combined proton-photon treatments, in which some fractions are delivered with protons and the remaining fractions with pho-tons, as an approach to maximize the benefit of limited proton therapy resources at a population level. Methods and Materials: To quantify differences in normal-tissue complication probability (NTCP) between protons and pho-tons, we considered a cohort of 45 patients with head and neck cancer for whom intensity modulated radiation therapy and intensity modulated proton therapy plans were previously created, in combination with NTCP models for xerostomia and dys-phagia considered in the Netherlands for proton patient selection. Assuming limited availability of proton slots, we developed methods to optimally assign proton fractions in combined proton-photon treatments to minimize the average NTCP on a pop-ulation level. The combined treatments were compared with patient selection strategies in which patients are assigned to sin-gle-modality proton or photon treatments. Results: There is a benefit of combined proton-photon treatments compared with patient selection, owing to the nonlinearity of NTCP functions; that is, the initial proton fractions are the most beneficial, whereas additional proton fractions have a decreasing benefit when a flatter part of the NTCP curve is reached. This effect was small for the patient cohort and NTCP models considered, but it may be larger if dose-response relationships are better known. In addition, when proton slots are limited, patient selection methods face a trade-off between leaving slots unused and blocking slots for future patients who may have a larger benefit. Combined proton-photon treatments with flexible proton slot assignment provide a method to make optimal use of all available resources. Conclusions: Combined proton-photon treatments allow for better use of limited proton therapy resources. The benefit over patient selection schemes depends on the NTCP models and the dose differences between protons and photons. (c) 2021 Elsevier Inc. All rights reserved.