Technologies to drastically boost photon sensitivity for brain-dedicated PET

大幅提高大脑专用 PET 光子灵敏度的技术

• 批准号: 9568754
• 负责人: CRAIG S LEVIN
• 金额: $ 41.09万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-25 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9568754
• 关键词: Address; Anatomy; Binding; Brain; Caliber; Clinical; Collection; Compton radiation; Coupled; Crystallization; Data; Detection; Development; Dimensions; Electronics; Elements; Event; Functional Magnetic Resonance Imaging; Goals; Human; Image; Incidence; Income; Length; Light; Magnetic Resonance; Magnetic Resonance Imaging; Measurement; Measures; Methods; Molecular; Neuromodulator; Neurotransmitter Receptor; Neurotransmitters; Noise; Patients; Performance; Photons; Positioning Attribute; Positron-Emission Tomography; Price; Process; Property; Recovery; Reporting; Research; Resolution; Sensory Receptors; Side; Signal Transduction; System; Techniques; Technology; Testing; Time; Tissues; Tracer; Translating; Translations; Width; Work; analog; cost effective; design; detector; digital; image reconstruction; improved; innovation; interest; kinematics; millisecond; neurochemistry; neuroimaging; next generation; novel; operation; photon-counting detector; receptor; receptor function; response; retinal rods; spatiotemporal; targeted treatment; two-dimensional; uptake; working group

Project Summary/Abstract According to the BRAIN 2025 working group report, there is a need to drastically improve the spatiotemporal resolution of positron emission tomography (PET), in order to facilitate the translation of new tracers that target neuroreceptor function and dynamic PET imaging on the milliseconds timescale. To address this challenge, we propose to demonstrate feasibility of a next generation annihilation photon detector module that, if successful, will serve as the fundamental building block of an advanced brain-dedicated PET system to be developed in follow-on work after this feasibility stage. This next-generation system design shows promise to transform the capabilities of PET in human neuroimaging through substantial (>10-fold) boosts in reconstructed image signal-to-noise ratio (SNR) and contrast-to-noise ration (CNR). Besides employing a smaller system diameter (e.g. 32 cm diameter) compared to the standard whole body PET system, this proposed enhancement is enabled by two unique features proposed (1) 100 picosecond (ps) coincidence time resolution (CTR), and (2) the ability to measure the energy and three-dimensional (3D) position of one or more annihilation photon interactions in the detector. These two new capabilities are achieved through a highly innovative scintillation detector configuration described in detail in the proposal. By precisely measuring the flight time of annihilation photons from their emission point within the patient to the detectors, the time-of-flight (TOF) PET technique enables a significant image SNR and CNR boost because it allows more events to be placed closer to their true point of emission along detector response lines of the system during the image reconstruction process. The key to better TOF-PET performance is to improve the annihilation photon pair CTR measured between any two detection elements in the system. Current commercially available PET systems achieve a CTR of roughly 350 to 800 ps full-width-at-half-maximum (FWHM). The proposed goal of 100 ps FWHM CTR alone represents a significant PET technology advance. But the novel detector configuration proposed also enables another capability not possible with the conventional PET detector. Owing to the fact that most incoming 511 keV photons undergo inter-crystal Compton scatter in the detectors, we can exploit the kinematics of that process to estimate the photon angle-of-incidence. If successful, that capability enables us to accurately position the first interaction of such multi-crystal events, but also offers the possibility to retain a high fraction of photon events that are normally rejected by a conventional PET system, such as single (unpaired) photons, random coincidences, tissue-scatter coincidences, and multiple (>2) photon coincidences. Since these normally-discarded events are over 10-fold more probable than true coincidence events in a standard PET study, this 3D position sensitive detector technology shows promise as another method to greatly boost photon sensitivity, and thus reconstructed image SNR. In this project we will design and develop two next-generation PET detectors and integrate them into MRI-compatible detector modules. The performance of these modules will be characterized outside and inside a 3 Tesla clinical MRI system to demonstrate feasibility of this concept.

项目摘要/摘要 根据大脑2025工作组报告，需要大幅度改善时空 正电子发射断层扫描（PET）的分辨率，以促进针对目标的新示踪剂的翻译 在毫秒的时间范围内的神经感受器功能和动态PET成像。为了应对这一挑战，我们 建议证明下一代灭绝光子检测器模块的可行性，如果成功， 充当高级脑专用宠物系统的基本构建块，将在后续开发 在这个可行性阶段工作。这种下一代系统的设计显示了有望改变的能力 通过重建的图像信号与噪声比例，通过大量（> 10倍）的增强（> 10倍）的宠物进行宠物 （SNR）和对比度对比度（CNR）。除了使用较小的系统直径（例如直径32厘米） 与标准的全身宠物系统相比，该提出的增强功能由两个独特的功能启用 提出的（1）100 picsecond（ps）重合时间分辨率（CTR），以及（2）测量能量和 检测器中一个或多个an灭光子相互作用的三维（3D）位置。这两个新 通过详细描述的高度创新闪烁检测器配置来实现功能 提议。通过精确测量从患者内部的发射点歼灭光子的飞行时间 检测器，飞行时间（TOF）PET技术可以实现重要的图像SNR和CNR的提升，因为它 允许将更多的事件放置在系统响应线上的真实发射点附近 在图像重建过程中。更好的TOF-PET性能的关键是改善歼灭 光子对CTR在系统中的任何两个检测元件之间进行了测量。当前的市售宠物 系统达到大约350至800 ps全宽度最大的CTR（FWHM）。提议的目标为100 ps 仅FWHM CTR就代表了一项重大的宠物技术进步。但是提出了新颖的探测器配置 同样，传统的宠物探测器不可能实现其他能力。由于大多数事实 传入的511 keV光子在检测器中经历晶体间的康普顿散射，我们可以利用的运动学 估计光子嵌入式的过程。如果成功，该功能使我们能够准确 定位此类多晶体事件的第一个相互作用，但也提供了保留大部分的可能性 通常被常规宠物系统拒绝的光子事件，例如单个（未配对）光子，随机 巧合，组织碎片的重合和多个（> 2）光子的重合。由于这些通常被认为是案子 在标准PET研究中，事件比真正的巧合事件要超过10倍，这是3D位置 敏感探测器技术显示出有望是大大提高光子灵敏度的另一种方法，因此 重建图像SNR。在这个项目中，我们将设计和开发两个下一代宠物探测器， 将它们集成到MRI兼容的检测器模块中。这些模块的性能将被表征 在3特斯拉临床MRI系统的外部和内部，以证明此概念的可行性。