Real-time in Vivo Dosimetry in Radiation Therapy Using Scintillation Detectors

说明（由申请人提供）：将正确的剂量输送到预期区域是任何放射治疗的最基本目标。确认输送到目标地点的真实剂量的最直接方法是就地测量该剂量。在前列腺放射治疗中，结果（生化和局部控制）取决于剂量按计划准确地输送到前列腺。同时，重要的是要确保对关键结构（直肠、尿道和勃起组织）的耐受性在可接受的范围内，这样毒性就会降到最低，生活质量也不会受到影响。我们假设基于剂量的适应性放疗可以通过测量输送到器官、关键结构和肿瘤附近的剂量来实现。我们相信这可以通过一个由多个探针组成的体内闪烁探测器来实现，该探测器按照特定的应用设计排列，可以实时监测真实的体内剂量。塑料闪烁探测器由三个主要组成部分构成：当辐射时发光（发射可见光）的微型闪烁材料，携带光的光导，以及将光转换为可测量信号的光电探测器。我们将使用亚毫米直径的闪烁纤维，因为它们的空间分辨率和灵活性，使它们符合内部解剖结构的曲率。为了实现这一目标，我们的目标是：a)建立光子和质子放疗光束中闪烁纤维的剂量学特征和特性；b)设计、构建和测试直肠和尿道体内应用的探测器系统；c)测量一小群患者的直肠壁和尿道剂量。该项目的成功完成将产生一种方法，用于监测放射治疗期间输送到有危险的器官和其他组织的真实剂量。该方法可用于生成数据以评估对器官和关键结构的剂量，并改变治疗计划以使对肿瘤的剂量最大化和/或使正常组织的并发症风险最小化。所得数据也可用于研究剂量相关的治疗副作用。利用这种方法的最终目的是改善放疗治疗的交付和放疗患者的生活质量。

DESCRIPTION (provided by applicant): Delivering the correct dose to the intended area is the most basic goal of any radiotherapy treatment. The most direct way to confirm the true dose delivered to a location of interest is to measure that dose in situ. In prostate radiotherapy, the outcome (biochemical and local control) depends on accurate delivery of the dose to the prostate as planned. At the same time, it is important to ensure that the tolerance to critical structures (rectum, urethra, and erectile tissues) is within acceptable limits so that toxicity is minimized and quality of life is not compromised. We hypothesize that dose-based adaptive radiotherapy is achievable by measuring the dose delivered to organs, critical structures, and within the vicinity of the tumor. We believe this can be done using an in vivo scintillation detector composed of multiple probes arranged in an application-specific design that can monitor true in vivo dose in real time. Plastic scintillation detectors are constructed from three main components: a miniature scintillating material that luminesces (emits visible light) when irradiated, an optical guide that carries the light, and a photodetector that converts the light into a measurable signal. We will use sub-millimeter diameter scintillating fibers for their spatial resolution as well as their flexibility, allowing them to conform to the curvatures of internal anatomy. In order to reach this goal, we aim to: a) establish the dosimetric characteristics and properties of scintillating fibers in photon and proton radiotherapy beams, b) design, construct, and test detector systems for rectal and urethral in vivo applications, and c) measure the dose to the rectal wall and urethra for a small cohort of patients. Successful completion of this project will result in a method for monitoring the true dose delivered to organs and other tissues at risk during radiotherapy. This method can be used to generate data to assess the dose to the organs and critical structures and alter the treatment plan to maximize the dose to the tumor and/or minimize the risk of complications to normal tissue. The resulting data can also be used to study dose- related treatment side effects. The ultimate goal of utilizing this method is to improve the delivery of radiotherapy treatments and the quality of life of radiotherapy patients.