Ultrafast FLASH radiation therapy dosimetry

项目总结 超快闪光照射剂量测量是一个尚未解决的临床和工程问题。这样做的目的是 研究是开发首个同类脉冲分辨超快辐射探测器原型，基于 用于闪光辐射的创新低增益雪崩探测器(LGAD)技术和超快电子学 治疗剂量学。我们最近在《医学和生物学中的物理学》上发表的研究表明，对于 第一次，LGAD传感器与相关的超快读出电子设备(国际专利号 WO2019232172A1)由堪萨斯大学开发，可以测量带电粒子通量 速度快，空间精度高。该系统已经在医用直线加速器上进行了测试，其中单粒子 是以50皮秒的时间分辨率测量的。综合响应与标准响应一样准确 电离室，但空间分辨率要精细20倍，时间分辨率超过1亿 测量单个直线加速器脉冲沉积的电荷的能力提高了一倍。史无前例的 分辨率允许查看公知的3微秒直线加速器脉冲的结构， 最引人注目的是，列车中350皮秒的子脉冲将被重建。该项目是对 PAR-19-150，旨在鼓励定量和物理科学家在生物医学领域工作 研究人员将催化使用生物工程方法，以挖掘其开辟新领域的潜力 生物医学调查。我们的目标是1)设计和建造LGAD剂量测量原型，这两个原型都是单元素的 以及具有1厘米间距的16元素阵列，以及2)确定原型是否可以用作超快和 比例剂量测量装置。这项概念验证研究为闪存提供了一种创新方法 有可能将剂量测量能力从毫秒扩大到微秒的剂量测量 甚至到纳秒。超快探测器可以被辐射生物学家用来获得准确的剂量 临床前动物研究中的评估，由闪光系统供应商允许在安全反馈中使用 可以在治疗期间阻止光束的系统，以及临床医学物理学家起到的两个- 用于闪光交付调试和患者特定质量保证的多维探测器阵列 质量控制。

PROJECT SUMMARY Ultrafast FLASH radiation therapy dosimetry is an unsolved clinical and engineering problem. The goal of this research is to develop a first-of-its-kind pulse-resolved ultrafast radiation detector prototype based on innovative low-gain-avalanche-detector (LGAD) technology and ultrafast electronics for FLASH radiation therapy dosimetry. Our recent work published in Physics in Medicine and Biology demonstrates that, for the first time, LGAD sensors with associated ultrafast readout electronics (International patent number WO2019232172A1) developed at the University of Kansas (KU) can measure charged particle fluences with high speed and spatial precision. The system has been tested with a medical LINAC where single particles were measured with a time resolution of 50 picoseconds. The integrated response is as accurate as a standard ionization chamber but with a spatial resolution twenty times finer and a temporal resolution over 100 million times better with the capability to measure the charges deposited by a single LINAC pulse. The unprecedented resolving power allows the structure of the commonly known 3-microsecod LINAC pulses to be viewed and, most strikingly, the 350-picosecond sub-pulses in the train to be reconstructed. This project is in response to PAR-19-150 which seeks to encourage quantitative and physical scientists to work with biomedical researchers to catalyze the use of bioengineering approaches for their potential to open new areas of biomedical investigation. We aim to 1) design and build a LGAD dosimetry prototype, both a single-element and a 16-element array with a 1-cm pitch, and 2) determine if the prototypes can function as an ultrafast and proportional dose measurement device. This proof-of-concept study provides an innovative method for FLASH dosimetry that has the potential to expand dose measurement capability from milliseconds to microseconds and even to nanoseconds. The ultrafast detectors can be used by the radiation biologists for accurate dose estimations in preclinical animal studies, by FLASH system vendors to allow their use in a safety feedback system that could stop a beam during treatment, and by the clinical medical physicists to function as a two- dimensional detector array for both FLASH delivery commissioning and patient-specific quality assurance and quality control.