PDF(Pubmed)
Abstract：
Objective. Lowering treatment costs and improving treatment quality are two primary goals for next-generation proton therapy (PT) facilities. This work will design a compact large momentum acceptance superconducting (LMA-SC) gantry beamline to reduce the footprint and expense of the PT facilities, with a novel mixed-size spot scanning method to improve the sparing of organs at risk (OAR).Approach. For the LMA-SC gantry beamline, the movable energy slit is placed in the middle of the last achromatic bending section, and the beam momentum spread of delivered spots can be easily changed during the treatment. Simultaneously, changing the collimator size can provide spots with various lateral spot sizes. Based on the provided large-size and small-size spot models, the treatment planning with mixed spot scanning is optimized: the interior of the target is irradiated with large-size spots (to cover the uniform-dose interior efficiently), while the peripheral of the target is irradiated with small-size spots (to shape the sharp dose falloff at the peripheral accurately).Main results. The treatment plan with mixed-size spot scanning was evaluated and compared with small and large-size spot scanning for thirteen clinical prostate cases. The mixed-size spot plan had superior target dose homogeneities, better protection of OAR, and better plan robustness than the large-size spot plan. Compared to the small-size spot plan, the mixed-size spot plan had comparable plan quality, better plan robustness, and reduced plan delivery time from 65.9 to 40.0 s.Significance. The compact LMA-SC gantry beamline is proposed with mixed-size spot scanning, with demonstrated footprint reduction and improved plan quality compared to the conventional spot scanning method.
摘要：
目的：降低治疗成本和提高治疗质量是下一代质子治疗（PT）设施的两个主要目标。这项工作将设计一个紧凑的大动量接受超导（LMA-SC）龙门束线，以减少PT设施的占地面积和费用，采用一种新颖的混合尺寸斑点扫描方法，以改善对高危器官（OAR）的保护。
方法:对于LMA-SC龙门光束线,可移动能量狭缝放置在最后一个消色差弯曲部分的中间，并且在治疗期间可以容易地改变所递送的斑点的束动量扩散。同时,改变准直器尺寸可以提供具有各种横向光斑尺寸的光斑。根据提供的大尺寸和小尺寸光斑模型，优化了混合点扫描的治疗计划：用大尺寸点照射目标的内部（以有效地覆盖均匀剂量的内部），而目标的外周用小尺寸斑点照射（以精确地形成外周的尖锐剂量衰减）。＆＃xD;主要结果：对13例临床前列腺病例进行了混合尺寸斑点扫描的治疗计划评估，并与小尺寸和大尺寸斑点扫描进行了比较。混合大小斑点计划具有优越的靶剂量均匀性，更好地保护OAR，并且比大尺寸点计划具有更好的计划鲁棒性。与小尺寸的现货计划相比，混合大小的现货计划具有可比的计划质量，更好的计划鲁棒性，并将计划交付时间从65.9s减少到40.0s。＆＃xD;意义：提出了采用混合尺寸点扫描的紧凑型LMA-SC龙门光束线，与传统的点扫描方法相比，具有减少的足迹和提高的计划质量。
