Water-Equivalent Plastic Scintillation Detectors for Small-Field Radiotherapy

描述（由申请人提供）：Standard Imaging，Inc.正在开发新一代辐射剂量计，用于小野剂量测定。这些小型探测器在诸如立体定向放射外科手术/立体定向放射治疗（SRS/SRT）、调强放射治疗（IMRT）、动态弧形治疗和断层治疗等临床应用中是需要的。使能技术是点闪烁探测器，它采用微型塑料闪烁体，通过光纤耦合到彩色PIN二极管探测器。小野放射治疗技术，如立体定向放射外科手术（SRS）或立体定向体放射治疗（SBRT），能够向肿瘤输送高辐射剂量，同时保护健康组织和有风险的器官。这些特殊而复杂的治疗方式使患者受益匪浅，并提供了传统放射治疗技术的实质性优势。由于SRS和SBRT治疗通常在单次或低分次治疗方案中输送整个治疗剂量，因此必须准确输送治疗。第一阶段产生了一个强大的，单点水当量闪烁剂量计，以准确地表征和测量小领域的剂量，并在交付之前验证这些特殊的治疗。当与Standard Imaging的双通道SuperMAX静电计搭配使用时，紧凑型、全面运行的塑料闪烁探测器（PSD）得到进一步增强。然而，PSD/SuperMAX静电计系统还不能与水扫描系统一起使用，因为它缺乏兼容的模拟信号输出。水扫描系统与SRS合适的探测器的协调使用对于在患者治疗之前准确有效地表征这些精确的辐射场至关重要。第二阶段项目的总体目标是将第一阶段的小场探测器从需要专用2通道静电计的台式系统过渡到多功能的完全商业化的医用辐射探测器。实现这一目标将通过以下方式推进第一阶段项目的成功：（1）通过开发一种通用兼容的探测器系统，极大地扩展PSD设备的有效性和市场潜力，该系统可完全取代现有医疗辐射测量设备（特别是水扫描系统）的电离室或二极管，（2）彻底优化探测器，以及（3）完全表征检测器以便于在典型临床环境中应用。在第二阶段研究成功完成后，标准成像将准备向市场提供一种特征良好的PSD，适用于SRS和SBRT中使用的小射野的精确剂量测定和质量保证，并且与现有的测量系统完全兼容。这种单点系统的进一步发展随后可以包括生成多点系统，例如用于患者剂量测定的2D阵列或用于水扫描的固定线性阵列。

DESCRIPTION (provided by applicant): Standard Imaging, Inc. is developing a new generation of radiation dosimeters for small field dosimetry. These small detectors are needed in clinical applications such as stereotactic radiosurgery/stereotactic radiotherapy (SRS/SRT), intensity modulated radiation therapy (IMRT), dynamic arc therapy, and tomotherapy treatments. The enabling technology is the point scintillation detector that employs a miniature plastic scintillator coupled to a color PIN diode detector via an optical fiber. Small field radiotherapy techniques such as stereotactic radiosurgery (SRS) or stereotactic body radiation therapy (SBRT) enable delivery of high radiation doses to tumors while sparing healthy tissue and organs at risk. These special and complex treatment modalities significantly benefit patients and offer substantial advantages over traditional radiotherapy techniques. Because SRS and SBRT treatments often deliver the entire therapeutic dose in a single or hypofractionated treatment regimen, the treatments must be delivered accurately. Phase I generated a robust, single-point water-equivalent scintillation dosimeter to accurately characterize and measure the dosimetry of small fields and to verify these special treatments before delivery. The compact, fully operational Plastic Scintillation Detector (PSD) is further enhanced when paired with Standard Imaging's dual-channel SuperMAX electrometer. However, the PSD/SuperMAX electrometer system cannot yet be used with water scanning systems because it lacks a compatible analog signal output. Coordinated use of a water scanning system with SRS-appropriate detectors is crucial to characterize these precise radiation fields accurately and efficiently before patient treatment. The overall goal of this Phase II project is to transition th Phase I small-field detector from a bench-top system requiring a specialized 2-channel electrometer to a versatile fully commercialized medical radiation detector. Achieving this goal will advance the successful Phase I project by (1) greatly expanding the effectiveness and market potential of PSD devices by developing a universally compatible detector system that could be fully used in place of an ionization chamber or diode with existing medical radiation measurement equipment, especially water scanning systems, (2) thoroughly optimizing the detector, and (3) fully characterizing the detector for easy application in typical clinical settins. At the successful completion of this Phase II study, Standard Imaging will be poised to deliver to the market a well-characterized PSD suitable for precise dosimetry and QA of small fields used in SRS and SBRT, and that is fully compatible with existing measurement systems. Further development of this single-point system subsequently could include generating multi-point systems such as 2D arrays for patient dosimetry or fixed linear arrays for water scanning.