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: 9420111
• 负责人: CRAIG S LEVIN
• 金额: $ 41.57万
• 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 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9420111
• 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工作组的报告，有必要大幅改善时空 正电子发射断层扫描(PET)的分辨率，以促进靶向的新示踪剂的平移 神经感受器功能和毫秒时间尺度上的动态PET成像。为了应对这一挑战，我们 建议证明下一代湮没光子探测器模块的可行性，如果成功，将 作为后续开发的高级脑部专用PET系统的基本组成部分 在这个可行性阶段之后再工作。这一新一代系统设计展示了将 通过大幅(10倍)提高重建图像的信噪比，PET在人类神经成像中的应用 (SNR)和对比噪声比(CNR)。除了采用较小的系统直径(例如，32厘米直径) 与标准的全身正电子发射计算机断层扫描系统相比，这种拟议的增强是由两个独特的功能实现的 提出了(1)100皮秒(Ps)符合时间分辨率(CTR)，以及(2)测量能量和 探测器中一个或多个湮没光子作用的三维(3D)位置。这两个新的 功能是通过高度创新的闪烁探测器配置实现的，详细说明请参阅 求婚。通过精确测量从患者体内的湮没光子发射点到 探测器，飞行时间(TOF)PET技术能够显著提高图像SNR和CNR，因为它 允许沿系统的探测器响应线将更多事件放置在更接近其真实发射点的位置 在图像重建过程中。提高TOF-PET性能的关键是提高湮没效率 系统中任意两个探测元件之间测量的光子对CTR。目前市面上可以买到的聚酯 系统的CTR约为350到800 ps的半高全宽(FWHM)。建议的100 PS的目标 FWHM CTR本身就代表着PET技术的重大进步。但新的探测器配置提出了 还实现了常规PET探测器无法实现的另一种能力。由于大多数人 入射的511keV光子在探测器中发生晶间康普顿散射，我们可以利用 这是估算光子入射角的过程。如果成功，该能力使我们能够准确地 定位这种多晶体事件的第一个相互作用，但也提供了保留高比例的 通常被常规PET系统拒绝的光子事件，例如单(未成对的)光子、随机 重合、组织散射重合和多(&gt；2)光子重合。因为这些通常会被丢弃 在标准的PET研究中，事件发生的可能性是真实巧合事件的10倍以上，这是3D位置 灵敏探测器技术显示出作为另一种极大提高光子灵敏度的方法的前景，因此 重建图像的信噪比。在这个项目中，我们将设计和开发两个新一代PET探测器和 将它们集成到与MRI兼容的探测器模块中。将对这些模块的性能进行表征 内外各一套特斯拉临床磁共振成像系统，论证了这一概念的可行性。