Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland; Maryland Proton Treatment Center, Baltimore, Maryland.
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland; Maryland Proton Treatment Center, Baltimore, Maryland.
Int J Radiat Oncol Biol Phys. 2024 Nov 15;120(4):1149-1158. doi: 10.1016/j.ijrobp.2024.06.009. Epub 2024 Jun 25.
Pencil-beam scanning proton therapy has been considered a potential modality for the 3D form of spatially fractionated radiation therapy called lattice therapy. However, few practical solutions have been introduced in the clinic. Existing limitations include degradation in plan quality and robustness when using single-field versus multifield lattice plans, respectively. We propose a practical and robust proton lattice (RPL) planning method using multifield and evaluate its dosimetric characteristics compared to clinically acceptable photon lattice plans.
Seven cases previously treated with photon lattice therapy were used to evaluate a novel RPL planning technique using 2-orthogonal beams: a primary beam (PB) and a robust complementary beam (RCB) that deliver 67% and 33%, respectively, of the prescribed dose to vertices inside the gross target volume (GTV). Only RCB is robustly optimized for setup and range uncertainties. The number and volume of vertices, peak-to-valley dose ratios (PVDRs), and volume of low dose to GTV of proton and photon plans were compared. The RPL technique was then used in the treatment of 2 patients and their dosimetric parameters were reported.
The RPL strategy was able to achieve the clinical planning goals. Compared to previously treated photon plans, the average number of vertices increased by 30%, the average vertex volume by 49% (18.2 ± 25.9 cc vs 12.2 ± 14.5 cc, P = .21), and higher PVDR (10.5 ± 4.8 vs 2.5 ± 0.9, P < .005) was achieved. In addition, RPL plans show more conformal dose with less low dose to GTV (V30%, 60.9% ± 7.2% vs 81.6% ± 13.9% and V10%, 88.3% ± 4.5% vs 98.6% ± 3.6% [P < .01]). The RPL plan for 2 treated patients showed PVDRs of 4.61 and 14.85 with vertices-to-GTV ratios of 1.52% and 1.30%, respectively.
A novel RPL planning strategy using a pair of orthogonal beams was developed and successfully translated to the clinic. The proposed method can generate better quality plans, a higher number of vertices, and higher PVDRs than currently used photon lattice plans.
铅笔束扫描质子治疗已被认为是一种用于称为格点治疗的三维空间分割放射治疗的潜在方式。然而，临床上很少有实用的解决方案。现有的局限性包括在使用单野和多野格点计划时，计划质量和稳健性分别下降。我们提出了一种实用的、稳健的质子格点（RPL）规划方法，使用多野，并与临床可接受的光子格点计划相比评估其剂量学特性。
使用 2 个正交光束（主射束 PB 和稳健互补射束 RCB）评估了一种新的 RPL 规划技术，这两种射束分别提供了处方剂量的 67%和 33%给 GTV 内部的顶点。只有 RCB 是为设置和范围不确定性进行稳健优化的。比较了质子和光子计划的顶点数量和体积、峰谷剂量比（PVDR）以及 GTV 的低剂量体积。然后，在 2 名患者的治疗中使用了 RPL 技术，并报告了他们的剂量学参数。
RPL 策略能够实现临床规划目标。与之前接受治疗的光子计划相比，平均顶点数量增加了 30%，平均顶点体积增加了 49%（18.2 ± 25.9 cc 比 12.2 ± 14.5 cc，P =.21），并实现了更高的 PVDR（10.5 ± 4.8 比 2.5 ± 0.9，P <.005）。此外，RPL 计划显示出更好的适形剂量，GTV 的低剂量更少（V30%，60.9% ± 7.2%比 81.6% ± 13.9%和 V10%，88.3% ± 4.5%比 98.6% ± 3.6%[P <.01]）。2 名接受治疗的患者的 RPL 计划显示出 4.61 和 14.85 的 PVDR，顶点与 GTV 的比率分别为 1.52%和 1.30%。
开发了一种使用一对正交射束的新型 RPL 规划策略，并成功转化为临床应用。与目前使用的光子格点计划相比，所提出的方法可以生成质量更好、顶点数量更多、PVDR 更高的计划。
