Probing optical property changes in photonic materials for faster timing in PET

描述（由申请人提供）：我们提出探索新的非线性光子材料，以使飞行时间（ToF）正电子发射断层扫描（PET）检测器具有<30皮秒（ps）的时间分辨率，而不是使用闪烁晶体的现有技术PET系统实现的500-900皮秒。 PET目前是癌症管理的“标准护理”，也是基础研究的重要工具。PET系统包括位置敏感闪烁探测器的环。PET扫描收集数百万个“事件”，包括在注射放射性造影剂后从患者发射的反向511千电子伏（keV）光子对。由系统探测器记录的这些双光子命中的测量分布用于重建代表示踪剂生物分布的3D图像体积，其用于表征和量化治疗前后的细胞和分子疾病状态。 如果成功的话，所提出的<30 ps的时间分辨率将使得能够沿着在PET系统中的任何两个511 keV湮灭光子探测器元件之间形成的响应线更准确和精确地定位正电子衰变事件。这项颠覆性技术将代表PET的巨大范式转变，因为它将彻底改变PET系统的运行方式。更多的事件将沿着沿着穿过患者的响应线被准确定位的事实使得能够实现显著的信号放大，以获得前所未有的可视化和量化疾病特征的能力。由此产生的巨大的图像信噪比（SNR）提升也可以用于将患者注射的放射性剂量或扫描时间减少100倍，这些惊人的功能将继续增加PET作为疾病管理护理标准的广泛使用，并为临床成像模式以及疾病分子机制的动物研究开辟新的角色。 为了实现<30 ps时间分辨率的目标，我们将探索非线性光子材料，其中光学参数的皮秒变化是常见的，并且使用现代光学方法测量，而不是使用闪烁探测器，闪烁探测器通过自发光发射过程和光电探测最多达到数百ps的时间分辨率。该项目将要求研究人员研究并获得几种候选的高Z，高密度光子材料;创建一个光学测试床，用于探索光子材料的快速时间特性;测量这些材料中电离诱导的光学特性调制;并研究与从这些新材料和方法构建实用PET探测器相关的“按比例放大”问题。这是一个令人兴奋的多学科项目，涉及物理学、光子学、光学、电气工程、放射学、计算机科学、材料科学、纳米科学和应用数学等领域的概念，目标是大幅改善ToF PET性能，推动癌症、心血管疾病和神经系统疾病的研究和临床管理取得重要进展。 以下包含机密信息，除用于审查和评估本提案外，不得使用。

DESCRIPTION (provided by applicant): We propose to explore new non-linear photonic materials to enable time-of-flight (ToF) positron emission tomography (PET) detectors with <30 pico-second (ps) time resolution, as opposed to 500-900 picoseconds achieved by state-of-the-art PET systems that use scintillation crystals. PET is currently the "standard-of-care" for cancer management and an important tool in basic research. A PET system comprises a ring of position sensitive scintillation detectors. A PET scan collects millions of "events" comprising pairs of oppositely-directed 511 kilo-electron- volt (keV) photons that are emitted from the patient after injection of a radioactive contrast agent. The measured distribution of these two-photon hits recorded by the system detectors is used to reconstruct a 3-D image volume that represents the tracer biodistribution, which is used to characterize and quantify cellular and molecular disease states before and after treatment. If successful, the proposed <30 ps time resolution will enable an order of magnitude more accurate and precise localization of a positron decay event along the response line formed between any two 511 keV annihilation photon detector elements in a PET system. This disruptive technology would represent a tremendous paradigm shift for PET as it would drastically change the way a PET system operates. The fact that many more events would be accurately positioned along a response line through the patient enables substantial signal amplification for unprecedented ability to visualize and quantify disease signatures. The resulting huge image signal-to-noise (SNR) boost could also be exploited to reduce patient injected radioactive dose or scan time by a factor of 100, amazing features that would both continue to increase PET's widespread use as the standard-of-care for disease management, as well as open up new roles for the imaging modality in the clinic as well as in animal research into molecular mechanisms of disease. To achieve our goal of <30ps time resolution, we will explore non-linear photonic materials where picosecond changes in optical parameters are common and measured using modern optics methods, rather than using scintillation detectors which at best achieve hundreds of ps time resolution through spontaneous light emission processes and photodetection. The project will require the investigators to research and obtain several candidate high Z, high-density photonic materials; create an optical test bed for exploring fast temporal properties of photonic materials; measure ionization-induced modulation of optical properties in these materials; and investigate "scaling up" issues relevant to building a practical PET detector from these novel material and methods. This is an exciting multi-disciplinary project that involves concepts in fields such as physics, photonics, optics, electrical engineering, radiology, computer science, materials science, nano-science, and applied mathematics with a goal of enabling substantial improvements in ToF PET performance to drive important advances in the study and clinical management of cancer, cardiovascular disease and neurological disorders. The following contains confidential information that should not be used except for purpose of review and evaluation of this proposal.