TOF-PET with high-efficiency TlCl crystals

具有高效 TlCl 晶体的 TOF-PET

基本信息

批准号：
10660173
负责人：
Gerard Ariño Estrada
金额：
$ 63.9万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-01 至 2027-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10660173
关键词：
Adoption Background Radiation Behavior Beryllium Biomedical Engineering Bismuth California Cardiovascular Diseases Cells Chlorides Coupled Data Detection Development Diagnosis Dimensions Discipline of Nuclear Medicine Dose Elements Evaluation Evolution Floods Foundations Generations Geometry Goals Growth Human Resources Image Indium Individual Iodine Light Love Lutetium Malignant Neoplasms Measures Modality Modeling Musculoskeletal Diseases Optics Pathology Performance Positron-Emission Tomography Preparation Process Production Property Radiation Radiation Monitoring Research Research Personnel Resolution Sampling Silicon Staging Structure Surface Techniques Testing Thallium Time Universities Width Yttrium cancer diagnosis cost detector experience flexibility imaging modality improved man melting models and simulation monitoring device novel nuclear imaging photomultiplier photonics physical property radiation detector scale up simulation temporal measurement theranostics uptake

项目摘要

Summary Time-of-flight positron emission tomography is a very effective nuclear imaging modality for the diagnosis and staging of a range of pathologies such as cancer, cardiovascular diseases, or musculoskeletal disorders. Commercial TOF-PET scanners currently employ lutetium-(yttrium)-oxyorthosilicate (L(Y)SO) crystal detectors coupled to silicon photomultipliers (SiPMs) to achieve coincidence time resolutions (CTR) between 200-500 ps full width at half maximum (FWHM). High production costs of L(Y)SO crystals and their intrinsic radiation background are currently hindering the evolution and spread of very promising TOF-PET modalities such as long axial field-of-view (LA-FOV) scanners or studies involving very low doses such as cell tracking or imaging with theranostic agents. New scintillator materials with lower production cost, radiation background-free, and with TOF-level timing accuracy are needed. We propose to use thallium chloride (TlCl) as a scintillator material for TOF-PET. TlCl is a material with a simple cubic structure that allows for a relatively easy and flexible doping process. Preliminary data obtained with TlCl crystals doped with beryllium (Be) and indium (I) show a very fast scintillation component of ~10 ns that has a high potential for very accurate timing measurements. TlCl has a greater detection efficiency than LYSO or even bismuth germanate (BGO) for 511 keV gammas, is background radiation-free, and its estimated production cost is 1/3 of L(Y)SO based on its low melting point of 430C (compared to 2050C for L(Y)SO) and simple lattice structure. Moreover, unlike BGO, TlCl uniquely combines a very fast scintillation process with a high Cherenkov generation yield to further boost timing potential. We aim to prove the feasibility of using TlCl detectors for TOF-PET by combining expertise in crystal growth, simulation of light generation and detection, and benchtop characterization. First, will study the effects of Be and I as dopants in TlCl with the aim of further improve the scintillation properties observed in the preliminary data. We will also optimize the surface treatment of TlCl to maximize the light extraction toward the photodetector. Second, we will develop a simulation framework that allows us to guide the crystal development process and to understand the fundamental timing limits of TlCl. Third, we will characterize individual TlCl crystals with different choices of photodetectors to evaluate their timing and energy resolution accuracy. Results obtained with these crystals will be used to tune and validate the simulation model as well. Finally, we will evaluate the performance of TlCl detector blocks of 4x4 crystal elements. We will evaluate their timing resolution, depth-of-interaction estimation accuracy, and quality of flood histograms.

概括飞行时间正电子发射断层扫描是一种非常有效的核成像方式，用于诊断和治疗一系列病理学的分期，例如癌症、心血管疾病或肌肉骨骼疾病。商用 TOF-PET 扫描仪目前采用镥-(钇)-氧原硅酸盐 (L(Y)SO) 晶体探测器与硅光电倍增管 (SiPM) 耦合，以实现 200-500 ps 之间的重合时间分辨率 (CTR) 半高全宽 (FWHM)。 L(Y)SO晶体的高生产成本及其固有的辐射背景目前阻碍了它的发展非常有前途的 TOF-PET 模式的演变和传播，例如长轴视场 (LA-FOV) 扫描仪或涉及极低剂量的研究，例如细胞追踪或使用新闪烁剂成像。需要生产成本较低、无辐射背景、具有TOF级授时精度的材料。我们建议使用氯化铊（TlCl）作为 TOF-PET 的闪烁体材料，TlCl 是一种简单的材料。立方结构，允许使用 TlCl 获得相对简单和灵活的掺杂过程。掺杂铍 (Be) 和铟 (I) 的晶体显示出 ~10 ns 的非常快的闪烁分量，具有 TlCl 具有比 LYSO 甚至更高的检测效率。 511 keV 伽玛的锗酸铋 (BGO)，无背景辐射，其预计生产成本是 L(Y)SO 的 1/3，基于其 430°C 的低熔点（L(Y)SO 的熔点为 2050°C）和简单晶格此外，与 BGO 不同，TlCl 独特地将非常快的闪烁过程与高切伦科夫相结合。发电良率进一步提高时序潜力。我们的目标是结合晶体生长方面的专业知识，证明使用 TlCl 探测器进行 TOF-PET 的可行性，首先，将研究 Be 和 Light 的影响。 I 作为 TlCl 中的掺杂剂，目的是进一步改善初步数据中观察到的闪烁特性。我们还将优化 TlCl 的表面处理，以最大限度地提高光电探测器的光提取率。其次，我们将开发一个模拟框架，使我们能够指导晶体开发过程并了解 TlCl 的基本时间限制第三，我们将表征不同的 TlCl 晶体。选择光电探测器来评估其时间和能量分辨率的准确性。晶体还将用于调整和验证仿真模型，最后，我们将评估性能。 4x4 晶体元件的 TlCl 探测器块我们将评估它们的定时分辨率、交互深度。估计精度和洪水直方图的质量。