发表机构
Stanford University School of Medicine; University of Wisconsin–Madison; University of Colorado Anschutz Medical Campus（斯坦福大学医学院; 威斯康星大学麦迪逊分校; 科罗拉多大学安舒茨医学校区）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究开发了开源参数化工具Collimator Creator，用于自动生成直线加速器临床前电子照射的Cerrobend准直器STL模型，并通过实验验证了其几何精度和剂量学性能。
AI 中文摘要
为基于直线加速器的临床前电子照射设计定制Cerrobend准直器是劳动密集型的，并且容易出现设计不一致的问题。我们开发了Collimator Creator（CC），这是一个开源参数化工作流程，可将孔径尺寸和夹具偏移转换为可打印的STL模型，用于准直器模具、准直器外壳、Cerrobend支架和束流减速器。我们制造并表征了两种设计：一个4.0 x 1.5 cm$^2$的双侧肺部准直器，居中于中心轴上；以及一个1.5 x 1.5 cm$^2$的单侧肺部准直器，带有7.5 mm的夹具偏移，每个准直器均配有15 mm厚的Cerrobend准直器和10 mm的PLA减速器。使用千伏级平面图像来评估孔径几何形状和铸造均匀性。使用放射变色胶片在常规和超高剂量率（UHDR）电子传输下，在Varian TrueBeam上测量半高全宽（FWHM）和80%-20%的半影，并在常规剂量率下使用电离室测量离轴泄漏。铸造的Cerrobend孔径与其指定设计的偏差小于0.2 mm。FWHM值在标称场尺寸的3%以内，在常规和UHDR传输下，半影范围为0.73至1.05 mm。在常规剂量率下，两种准直器在准直器边缘外2 cm处的交叉线泄漏均低于2%。参数化准直器生成为两个评估的矩形直线加速器电子场标准化了数字设计输入。进一步的工作将评估标本级剂量测定、额外的孔径几何形状以及蒙特卡洛集成。
英文摘要
Designing custom Cerrobend collimators for linac-based preclinical electron irradiation is labor intensive and susceptible to design inconsistencies. We developed Collimator Creator (CC), an open source parametric workflow that converts aperture dimensions and jig offsets into printable STL models for a collimator mold, collimator shell, Cerrobend holder, and beam degrader. Two designs were fabricated and characterized: a 4.0 x 1.5 cm$^2$ bilateral lung collimator centered on the central axis and a 1.5 x 1.5 cm$^2$ unilateral lung collimator with a 7.5 mm jig offset, each with a 15 mm thick Cerrobend collimator and a 10 mm PLA degrader. Kilovoltage planar images were used to assess aperture geometry and casting uniformity. Radiochromic film was used to measure full width at half maximum (FWHM) and 80%-20% penumbra under conventional and ultra high dose rate (UHDR) electron delivery on a Varian TrueBeam, and off axis leakage was measured with an ionization chamber at conventional dose rate. The cast Cerrobend apertures deviated by less than 0.2 mm from their specified designs. FWHM values were within 3% of the nominal field dimensions, and penumbra ranged from 0.73 to 1.05 mm under conventional and UHDR delivery. Crossline leakage 2 cm beyond the collimator edge was below 2% for both collimators at conventional dose rate. Parametric collimator generation standardized digital design inputs for the two evaluated rectangular linac-based electron fields. Further work will assess specimen-level dosimetry, additional aperture geometries, and Monte Carlo integration.
Comments11 pages, 3 figures. Code: https://github.com/wizrads/CollimatorCreator
