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、患者解剖的日常变化以及治疗过程中受照射组织的整体反应，个别质子治疗束的剂量沉积特征存在不确定性，因此无法充分发挥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比理想的更大的“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向肿瘤提供适当的剂量。对这些大边际的需求严重限制了我们利用质子布拉格峰的尖锐剂量梯度的能力，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射程的不确定性，从而降低安全裕度并使用更优化的处理束，从而使质子布拉格峰的物理优势得以发挥。幸运的是，质子治疗所固有的是由于辐照组织中质子-核的非弹性相互作用而产生的元素“迅速”伽马射线(PG)的发射。组织中的每个元素沿着患者体内的光束路径发出独特的PG能量谱，使其成为光束距离验证的主要信号。我们假设，如果治疗过程中的PG排放能够被充分测量和成像，它将允许在体内直接验证所传递的射束范围。我们的长期目标是通过监测体内照射的射束距离和组织反应来提高质子放射治疗的准确性和精密度。为了实现这一目标，我们建立了学术和产业合作伙伴关系，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。这项建议的具体目标是：(1)建立高效的PG检测系统，(2)开发PG图像显示和评估的临床平台，以及(3)在患者治疗期间对我们的PGI系统进行功能表征和初步试点/评估研究。这项拟议的研究将导致开发一种临床PGI系统，用于质子放射治疗期间的活体成像。这将允许测量实际的体内剂量传递，从而减少质子束射程的固有不确定性。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”裕度的需求，以解决射程的不确定性，以此作为确保治疗安全和准确性的一种手段。

 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.