Prompt Gamma Imaging for the in-vivo range verification during proton radiotherapy

 描述（由申请人提供）：由于患者设置错误、患者解剖结构的日常变化以及治疗过程中辐照组织的总体反应导致单个质子治疗射束的剂量沉积特征存在不确定性，因此无法充分利用质子治疗的全部潜力。因此，目前的标准质子治疗技术包括使用大于期望的“治疗裕度”和“安全裕度”，以确保在存在这些不确定性的情况下将适当的剂量递送到肿瘤。对这些大裕度的需求严重限制了我们利用质子布拉格峰的急剧剂量梯度的能力，从而降低了质子放射治疗的全部临床潜力。因此，为了充分利用质子布拉格峰的优势，迫切需要减少质子束范围的不确定性，从而减少安全裕度并使用更优化的治疗束，从而允许质子布拉格峰的物理优势被利用。幸运的是，质子治疗固有的是由于被照射组织中的非弹性质子-核相互作用而发射元素“瞬发”伽马射线（PG）。组织中的每个元素沿患者体内的射束路径沿着发射PG能量的唯一光谱，使其成为射束范围验证的主要信号。我们假设，如果治疗输送过程中的PG发射可以充分测量和成像，它将允许直接验证体内输送的光束范围。我们的长期目标是通过监测射束范围和体内组织对照射的反应来提高质子放射治疗的准确性和精确性。为了实现这一目标，我们已经建立了一个工作的学术-工业合作伙伴关系，致力于将我们的原型快速伽马成像（PGI）系统转化为临床可行的系统。本提案的具体目标是：（1）构建一个高效的PG检测系统，（2）开发一个用于PG图像显示和评价的临床平台，以及（3）在患者治疗过程中表征PGI系统的功能并进行初步试点/评价研究。拟议的研究将导致在质子放射治疗过程中的体内成像的临床PGI系统的发展。这将允许测量实际的体内剂量输送，从而降低质子束范围的固有不确定性。通过测量和验证射束范围，我们可以减少甚至消除对大的“治疗安全”裕度的需要，以考虑范围不确定性，作为确保治疗安全性和准确性的手段。

 DESCRIPTION (provided by applicant): The full potential of proton therapy cannot be fully exploited due to uncertainties in the dose deposition characteristics of individual proton treatment beams caused by patient set-up errors, day- to-day changes in patient anatomy, and the overall response of irradiated tissues over the course of treatment. Therefore, current standard proton treatment techniques include the use of larger than desirable "treatment margins" and "safety margins" to ensure proper dose is delivered to the tumor in the presence of these uncertainties. The need for these large margins severely limits our ability to exploit the proton Bragg Peak's sharp dose gradients, thus reducing the full clinical potential of proton radiation therapy. Therefore, in order to fully exploit the advantages of the proton Bragg peak, there is a significant and critical need to reduce proton beam range uncertainties, allowing for the reduction of safety margins and the use of more optimal treatment beams, thus allowing the physical advantages of the proton Bragg peak to be exploited. Fortunately, inherent to proton therapy is the emission of elemental `prompt' gamma rays (PG) due to non-elastic proton-nucleus interactions in irradiated tissues. Each element in tissue emits a unique spectrum of PG energies along the path of the beam in the patient, making it a prime signal for beam range verification. We hypothesize that if PG emission during treatment delivery could be adequately measured and imaged, it would allow for the direct verification of the delivered beam range in-vivo. Our long-term goal is to improve the accuracy and precision of proton radiotherapy by monitoring the beam range and tissue response to irradiation in- vivo. To reach this goal, we have established a working academic-industrial partnership dedicated to the translation of our prototype prompt gamma imaging (PGI) system into a clinically viable system. The specific aims of this proposal are to: (1) build an efficient PG detection system, (2) develop a clinical platfor for PG image display and evaluation, and (3) characterize the functionality and perform initial pilot/evaluation studies our PGI system during patient treatment delivery. The proposed research will result in the development of a clinical PGI system for in-vivo imaging during proton radiotherapy treatment delivery. This will allow the measurement of the actual in-vivo dose delivery, thus reducing the inherent uncertainty in proton beam range. By measuring and verifying the beam range, we can reduce or even eliminate the need for large "treatment safety" margins to account for range uncertainty as a means of ensuring treatment safety and accuracy.