Product Development of Intensity Modulation for Bolus Electron Conformal Therapy

项目总结/摘要 目的：提高电子束治疗技术，为临床提供有效的治疗手段， 浅表癌（深度<6 cm）的放射治疗，与其他外部放射治疗（XRT）相比， 例如X射线和质子，通过将电子强度调制引入临床。挑战：大约 10%的放射治疗患者（美国每年有173，000人）接受EBT作为其治疗的一部分， 其中10%（每年17，300人）可能受益于团注电子适形治疗（BECT）， 使远端90%剂量表面符合癌性计划靶体积（PTV），保护邻近的 健康组织目前，放射肿瘤学家在使用BECT方面受到限制，因为PTV剂量扩散可能与 大至30%，由于不规则的团表面。通过对入射光进行空间调制， 电子束强度因此，电子强度调制传输技术一直不可用。 创新：使用我们的研究合作者最近发明的电子强度调制器设计，第一阶段 演示了PRIME（电子被动放射治疗强度调制器）的原理验证， 低成本技术，为此，decimal开发了一种制造方法。PRIME由一个小矩阵组成， 直径，圆柱形钨岛块嵌入在低密度泡沫在梁定义， 准直孔径不同直径的岛块放置在一个六边形网格达到所需的强度 调变然而，由于当前的治疗计划系统（TPS）不能管理PRIME， 电子TPS也需要开发。研究设计：第二阶段的具体目标包括（1）完善 笔形射束重定义算法，用于岛块下的剂量计算，（2）创建和评估 电子特定TPS，COMET计划（计算机优化和调制电子治疗计划）， 其计划强度调制团注电子适形治疗（IM-BECT）和常规EBT， 管理皮肤准直器和眼罩等治疗辅助设备，（3）开发工厂和临床PRIME 质量保证方法，（4）进行多机构治疗计划研究，以确定 IM-BECT改善BECT剂量计划的程度，以及（5）通过以下方式验证IM-BECT计划和输送： 将拟人幻影中测量的剂量与计划（计算）剂量进行比较。健康福利： PRIME设备和COMET计划软件将允许一种新的技术，IM-BECT，它提供了统一的 符合PTV的剂量，导致（1）同样高的癌症控制机会，（2）同样或更低的 急性正常组织并发症的机会，和（3）减少继发性癌症的机会。对于一些 患者，这将提供比其他XRT模式更好的剂量分布，例如体积弧形治疗 或螺旋断层放射治疗，改善他们的癌症治疗。商业化：作为世界领先的 作为一家生产患者专用放射治疗设备的公司，我们配备了良好的设备， 调制器和COMET-Plan软件应用于放射治疗诊所，支持令人兴奋的新型IM-BECT。

Project Summary/Abstract Objective: This project aims to elevate electron beam therapy (EBT) technology, which provides effective radiation treatment for superficial cancers (depth<6 cm), to that of other external beam radiotherapies (XRT), e.g. x-rays and protons, by bringing electron intensity modulation into the clinic. Challenge: Approximately 10% of radiotherapy patients (173,000 in USA annually) receive EBT for a portion of their treatment, and as many as 10% of these (17,300 annually) might benefit from bolus electron conformal therapy (BECT), which conforms the distal 90% dose surface to the cancerous planning target volume (PTV), protecting adjacent healthy tissue. Currently, radiation oncologists are limited in using BECT because PTV dose spread can be as great as 30% due to irregular bolus surface. This can be reduced to 10% by spatially modulating incident electron beam intensity. Heretofore, electron intensity modulation delivery technology has been unavailable. Innovation: Using our research collaborator’s recently invented electron intensity modulator design, Phase I demonstrated proof-of-principle for a PRIME (Passive Radiotherapy Intensity Modulator for Electrons), a low cost technology for which .decimal developed a fabrication method. PRIME consists of a matrix of small- diameter, cylindrical tungsten island blocks imbedded in a low-density foam in the beam-defining, collimating aperture. Varying diameters of island blocks placed on a hexagonal grid achieves desired intensity modulation. However, because current treatment planning systems (TPS) cannot manage PRIMEs, an electron TPS needs to be developed as well. Research Design: Phase II specific aims include (1) refining the pencil beam redefinition algorithm used for dose calculation under island blocks, (2) creating and evaluating an electron specific TPS, COMET-Plan (Computer Optimized & Modulated Electron Therapy Planning), which plans intensity modulated bolus electron conformal therapy (IM-BECT) and conventional EBT, managing treatment aids such as skin collimators and eye shields, (3) developing factory and clinical PRIME quality assurance methods, (4) performing a multi-institutional treatment planning study to determine the degree to which IM-BECT improves BECT dose plans, and (5) validating IM-BECT planning and delivery by comparing doses measured in anthropomorphic phantoms with planned (calculated) doses. Health Benefit: PRIME devices and COMET-Plan software will allow a new technique, IM-BECT, which provides uniform dose conforming to the PTV, resulting in (1) equally high chance of cancer control, (2) equally or better low chance of acute normal tissue complications, and (3) decreased chance of secondary cancers. For some patients, this will provide a better dose distribution than other XRT modalities, such as volumetric arc therapy or helical tomotherapy, improving their cancer treatment. Commercialization: As the world’s leading company producing patient-specific radiotherapy devices we are well equipped for bringing PRIME intensity modulators and COMET-Plan software to radiotherapy clinics, supporting the exciting, new IM-BECT.