Real-time volumetric scintillation dosimetry for radiation therapy

描述（由申请人提供）： 适形放射治疗的目标是向肿瘤提供治疗性放射剂量，同时保留附近的健康组织。在强度调制质子治疗（IMPT）中，这是通过在整个靶体积中递送不同尺寸和范围的许多质子笔形射束来实现的，并且在强度调制[光子]放射治疗（IMRT）和相关模态中，这是通过使用多叶准直器对放射射束进行成形来实现的。由此产生的剂量分布可能非常复杂，必须通过详细的3D测量进行验证。当前的2D剂量测量设备可能会错过计划剂量和输送剂量之间的重要差异，因为它们不能测量完整的3D剂量分布。目前还没有合适的探测器可用于准确、高分辨率和高效的3D剂量 用于验证复杂光子和质子剂量分布的测量。我们的长期目标是通过开发一种用于患者治疗验证的新型快速、可重复使用的3D探测器来减少放射治疗错误并提高剂量验证精度。拟议的研究的目的是开发一个三维探测器的基础上，从一个大体积的闪烁体的光发射的测量，并使用该探测器获得IMPT和IMRT治疗的质量保证测量。在我们前期工作的基础上，我们假设体积闪烁探测器可以在真实的时间内测量3D剂量分布，精度为-3%或更好。该项目的基本原理是，它将实现完整的在线高分辨率3D剂量测量，作为每位患者常规QA的一部分，同时大大减少治疗验证所需的时间。为了实现这一目标，我们的目标是：a）开发仪器和重建技术，以测量三维光分布的体积闪烁体探测器，B）开发淬火校正方法的质子束闪烁剂量测定，和c）验证三维闪烁探测器的放射治疗验证。该研究将为放射治疗质量保证提供一个全三维剂量学系统，具有重要意义。该系统将是有效的和具有成本效益的，并将提高对输送给患者的剂量分布的信心。它还将减少验证测量所需的时间，消除主要的工作流程瓶颈，并使更多的患者受益于IMPT和其他复杂的放射治疗方式。随着全国和全球质子治疗中心数量的迅速增加，这一点尤为重要。拟议的项目是高度创新的意义上说，它将导致第一个其类型的剂量测定系统能够即时测量复杂的三维剂量分布。此外，我们希望这种探测器是有价值的其他治疗方式，包括立体定向体放射治疗，被动散射质子治疗，甚至高剂量率近距离放射治疗的三维剂量测定。

DESCRIPTION (provided by applicant): The goal of conformal radiation therapy is to deliver a curative radiation dose to the tumor while sparing nearby healthy tissue. In intensity modulated proton therapy (IMPT), this is accomplished by delivering many proton pencil beams of different sizes and ranges throughout the target volume, and in intensity modulated [photon] radiation therapy (IMRT) and related modalities, this is accomplished by shaping the radiation beam using a multi-leaf collimator. The resulting dose distributions can be highly complex, and must be verified by detailed 3D measurements. Current 2D dose measuring devices may miss vital differences between the planned and delivered doses because they cannot measure the full 3D dose distribution. At this time there are no suitable detectors available for accurate, high resolution, and efficient 3D dose measurement for verification of complex photon and proton dose distributions. Our long-term goal is to reduce radiation treatment errors and improve dose verification accuracy by developing a new fast, reusable 3D detector for patient treatment verification. The objective of the proposed research is to develop a 3D detector based on the measurement of light emission from a large volume of scintillator, and use this detector to obtain quality assurance measurements for IMPT and IMRT treatments. On the basis of our preliminary work, we hypothesize that a volumetric scintillation detector can measure 3D dose distributions in real time with an accuracy of �3% or better. The rationale for this project is that it will enable complete on-line high-resolution 3D dose measurements as a part of routine QA for each patient, while decreasing considerably the time required for treatment verification. To reach this goal, we aim to: a) develop instrumentation and reconstruction techniques to measure 3D light distributions in a volumetric scintillator detector, b) develop quenching correction methods for scintillation dosimetry of proton beams, and c) validate the 3D scintillation detector for radiotherapy treatment verification. The proposed research is significant because it will produce a fully three-dimensional dosimetry system for radiotherapy quality assurance. The system will be efficient and cost effective and will improve confidence in dose distributions delivered to patients. It will also decrease the time required for verification measurements, removing a major workflow bottleneck and allowing more patients to benefit from IMPT and other complex radiotherapy modalities. This is particularly important with the rapid increase in the number of proton therapy centers nationwide and worldwide. The proposed project is highly innovative in the sense that it will lead to a first-of-its-kind dosimetry system capable of instantaneously measuring complex 3D dose distributions. In addition, we expect this detector to be valuable for 3D dosimetry of other treatment modalities, including stereotactic body radiation therapy, passive scattering proton therapy, and even high-dose rate brachytherapy.