Background: Radiotherapy technology has undergone significant advancements, driven by the pursuit of improved tumor control probabilities and reduced normal tissue complication probabilities. This has been achieved primarily through innovative approaches that prioritize high dose conformity on complex treatment targets. The CONVERAY project introduces a groundbreaking teletherapy system featuring a convergent X-ray beam, which enables highly conformal dose distributions by converging photons to a focal spot, thereby achieving exceptionally high fluence rates. Methods: Customized Monte Carlo subroutines have been developed to simulate particle fluence and associated dosimetry effects for the CONVERAY device. This simulation approach facilitated a detailed, step-by-step characterization of radiation fluence and interaction processes, enabling seamless integration with a conventional clinical linear accelerator head. Key physical properties of the radiation beam have been comprehensively characterized for various CONVERAY configurations, providing a solid foundation for evaluating the corresponding dosimetry performance. Results: Monte Carlo simulations successfully tracked the phase state of the CONVERAY device, characterizing the influence of individual components on convergent photon beam production. Simulations evaluated dosimetry performance, confirming the device’s capability to achieve high dose concentrations around the focal spot. Preliminary tests on realistic scenarios (intracranial and pulmonary irradiations) demonstrated promising spatial dose concentration within tumor volumes, while gantry rotation significantly improved dose conformation. Conclusions: This proof-of-concept Monte Carlo study of the CONVERAY prototype provided critical insights into the generation of convergent X-ray beams, validating the device’s ability to achieve its primary objective. Notably, simulation results reveal the potential for exceptionally high dose concentrations within complex treatment volumes, demonstrating promising dosimetry performance.
背景：放疗技术已取得显著进步，这主要得益于对提高肿瘤控制概率和降低正常组织并发症概率的追求。这一进步主要通过创新方法实现，这些方法优先考虑对复杂治疗靶区的高剂量适形性。CONVERAY项目引入了一种开创性的远距放射治疗系统，该系统采用会聚X射线束，通过将光子会聚至焦点实现高度适形的剂量分布，从而获得极高的注量率。 方法：本研究开发了定制化的蒙特卡洛子程序，用于模拟CONVERAY装置的粒子注量及相关剂量学效应。该模拟方法实现了对辐射注量及相互作用过程的逐步详细表征，并能与常规临床直线加速器机头无缝集成。研究全面表征了不同CONVERAY配置下辐射束的关键物理特性，为评估相应剂量学性能奠定了坚实基础。 结果：蒙特卡洛模拟成功追踪了CONVERAY装置的相位状态，明确了各组件对会聚光子束产生的影响。模拟评估了剂量学性能，证实了该装置能在焦点周围实现高剂量集中。在真实场景（颅内和肺部照射）的初步测试中，肿瘤体积内显示出良好的空间剂量集中性，而机架旋转则显著改善了剂量适形度。 结论：这项针对CONVERAY原型的蒙特卡洛概念验证研究，为会聚X射线束的产生提供了关键见解，验证了该装置实现其主要目标的能力。值得注意的是，模拟结果表明该装置在复杂治疗体积内具有实现超高剂量集中的潜力，展现出良好的剂量学性能前景。
Development and Validation of Monte Carlo Methods for Converay: A Proof-of-Concept Study
肿瘤(癌症)患者之家