Leveraging ultra-fast Cherenkov emission in scintillator-based TOF-PET by exploiting photon wavelength classification

通过利用光子波长分类，在基于闪烁体的 TOF-PET 中利用超快切伦科夫发射

• 批准号: 10659114
• 负责人: Javier Caravaca Rodriguez
• 金额: $ 20.19万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10659114
• 关键词: Aluminum; Bismuth; Cardiovascular Diseases; Chlorides; Classification; Coupled; Detection; Diagnosis; Disease; Disparity; Dose; Electrons; Ensure; Event; Future; Gadolinium; Gallium; Gamma Rays; Germanium; Goals; Grant; Hybrids; Image; Image Enhancement; Lead; Light; Malignant Neoplasms; Measures; Modality; Modernization; Motivation; Nature; Noise; Optics; Oxides; Patients; Performance; Photons; Positron; Positron-Emission Tomography; Radioactive; Resolution; Safety; Signal Transduction; System; Techniques; Technology; Thallium; Time; Work; absorption; accurate diagnosis; cancer type; cost effective; design; detector; frontier; high reward; high risk; imaging capabilities; imaging modality; improved; light emission; millimeter; nanosecond; nervous system disorder; new technology; next generation; novel; nuclear imaging; optical spectra; photon-counting detector; prototype; quantum; standard of care; success; transmission process; Aluminum; Bismuth; Cardiovascular Diseases; Chlorides; Classification; Coupled; Detection; Diagnosis; Disease; Disparity; Dose; Electrons; Ensure; Event; Future; Gadolinium; Gallium; Gamma Rays; Germanium; Goals; Grant; Hybrids; Image; Image Enhancement; Lead; Light; Malignant Neoplasms; Measures; Modality; Modernization; Motivation; Nature; Noise; Optics; Oxides; Patients; Performance; Photons; Positron; Positron-Emission Tomography; Radioactive; Resolution; Safety; Signal Transduction; System; Techniques; Technology; Thallium; Time; Work; absorption; accurate diagnosis; cancer type; cost effective; design; detector; frontier; high reward; high risk; imaging capabilities; imaging modality; improved; light emission; millimeter; nanosecond; nervous system disorder; new technology; next generation; novel; nuclear imaging; optical spectra; photon-counting detector; prototype; quantum; standard of care; success; transmission process

Project Summary (Abstract) We propose to separate scintillation and Cherenkov photons produced in scintillator crystals to improve the time and energy resolution of time-of-flight positron emission tomography (TOF-PET) detectors far beyond those achieved in state-of-the-art systems. With its pico-molar sensitivity and a few millimeters of spatial resolution, TOF-PET is the leading nuclear imaging modality for a number of diseases, from cancer to neurological and cardiovascular disorders. A significant improvement of the coincidence time resolution (CTR) and energy resolution would boost the signal-to-noise ratio and hence enhance image quality, resulting in more accurate diagnoses, lower patient doses and exposure times, and granting access to a new broad range of applications for TOF-PET. The ultra-fast picosecond emission of Cherenkov light has demonstrated to achieve the best CTR ever reached of 30ps FWHM using PbF2, a pure Cherenkov emitter. However, this provides a very poor energy resolution due to the low light yield of Cherenkov emission. The combination of Cherenkov and scintillation emission has been proposed as a way to obtain both good time and energy resolution, which has been demonstrated in bismuth germanium oxide (BGO), a high stopping power scintillator for PET, to obtain a CTR of 120ps FWHM with an energy resolution of 14%. The main reason why it is very challenging for BGO to reach CTRs of 30ps FHWM is due to the presence of the slower scintillation light and the inability of current detectors to disentangle between Cherenkov and scintillation. Additionally, the difference between the Cherenkov and scintillation light emission spectra, makes it very hard to obtain a BGO detector that provides both good time and energy resolution. We propose to separate Cherenkov and scintillation photons in order to provide a detector that can be optimized independently for each of the signals, maximizing time resolution with Cherenkov and energy resolution with scintillation without hindering each other. This separation can be achieved by exploiting the different emission spectra of each mechanism using dichroic filters, which are able to classify photons by wavelength with a negligible photon loss. This project aims to 1) obtain a CTR of 50ps FWHM and reduce the scintillation background by a factor of 5 through wavelength classification in BGO, 2) increase photon detection efficiency in BGO by at least a factor of 2 without compromising time resolution, and 3) reach a CTR of 30ps FWHM with a 7% energy resolution by leveraging the hybrid Cherenkov-scintillation concept with thallium chloride (TlCl). This project will pioneer the exploration of wavelength information as a way to dramatically improve TOF-PET performance. We will combine this technique with other cutting-edge technologies such as fast or high quantum efficiency photosensors, in order to demonstrate a novel a cost- effective approach to a next generation TOF-PET. Our goal is to enable a new technology that can bring CTR closer to the 10ps FWHM milestone with a good energy resolution in order to be further exploited in future projects for the construction of a full TOF-PET system.

项目摘要（摘要） 我们建议分离闪烁体晶体产生的闪烁和cherenkov光子，以改善时间 飞行时间正电子发射断层扫描（TOF-PET）检测器的能量解决方案远远超出了这些检测 在最新系统中实现。具有Pico摩尔敏感性和几毫米的空间分辨率， TOF-PET是多种疾病的主要核成像方式，从癌症到神经系统和 心血管疾病。重合时间分辨率（CTR）和能量的显着改善 分辨率将提高信噪比，从而提高图像质量，从而更准确 诊断，较低的患者剂量和暴露时间，并授予对新的广泛应用的访问 对于tof-pet。 Cherenkov Light的超快速皮秒发射已证明可以达到最佳的CTR 使用PBF2（纯Cherenkov的发射极）达到30PS FWHM。但是，这提供了非常糟糕的能量 由于Cherenkov发射的低光收益率而导致的分辨率。切伦科夫和闪烁的结合 已经提出了排放作为获得美好时光和能量解决的一种方式， 在宠物的高停止功率闪烁体氧化物（BGO）中证明 120PS FWHM，能量分辨率为14％。 BGO到达非常具有挑战性的主要原因 30PS FHWM的CTR是由于存在较慢的闪烁光和电流检测器的无法 在Cherenkov和闪烁之间解开。此外，Cherenkov和 闪烁的光发射光谱使得很难获得提供美好时光和的BGO探测器 能源分辨率。我们建议将Cherenkov和闪烁光子分开，以提供检测器 可以针对每个信号独立优化，从而最大程度地分辨出与Cherenkov的时间分辨率和 闪烁的能量分辨率而不会互相阻碍。可以通过利用来实现这种分离 每种机制的不同发射光谱都使用二分色滤镜，能够通过 波长具有可忽略的光子损失。该项目的目的是1）获得50PS FWHM的CTR并减少 BGO中的闪烁背景为5倍至波长分类，2）增加光子 BGO中的检测效率至少为2倍，而不会损害时间分辨率，3）到达 通过利用混合动力Cherenkov-scintillation，CTR的30PS FWHM具有7％的能量分辨率 氯化硫酸硫酸盐（TLCL）的概念。该项目将开创对波长信息的探索 显着改善TOF-PET性能的方法。我们将将这一技术与其他尖端结合在一起 为了证明小说的成本 - 下一代TOF-PET的有效方法。我们的目标是启用一种可以带来CTR的新技术 更靠近10PS FWHM里程碑，并以良好的能量解决方案，以便将来进一步利用 建造完整TOF-PET系统的项目。