Tl-Halide Scintillators for TOF-PET

用于 TOF-PET 的卤化铊闪烁体

• 批准号: 10653275
• 负责人: JAROSLAW GLODO
• 金额: $ 64.72万
• 依托单位: RADIATION MONITORING DEVICES, INC.
• 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 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10653275
• 关键词: Address; Alzheimer' s Disease; Biological; Biological Process; California; Carbon Isotopes; Coupled; Craniocerebral Trauma; Crystallization; Detection; Development; Diagnosis; Disease; Exhibits; Exposure to; Face; Fluorine; Functional Imaging; Goals; Image; Imaging Techniques; Ions; Label; Length; Light; Malignant Neoplasms; Methods; Nitrogen; Noise; Oxygen; Patients; Performance; Phase; Photons; Positron; Positron-Emission Tomography; Production; Property; Radiation; Radiation exposure; Resolution; Scanning; Scheme; Semiconductors; Stroke; Structure; Symptoms; System; Technology; Testing; Thick; Time; Universities; analog; base; cold temperature; cost; density; detection sensitivity; detector; improved; in vivo; interest; luminescence; melting; response; simulation; virtual

Project Summary The current detector technology in PET requires scintillation that has fast response, excellent timing resolution, high detection sensitivity, good energy resolution, and last but not least acceptable cost. At present, most PET systems use crystals of LSO (Lu2SiO5:Ce) or its analog LYSO, which satisfy many of the listed requirements. But LSO, after years of development, has reached its performance limit, especially for the scanners with a long axial field of view (AFOV) that are currently being developed. The goal of these scanners is to increase the geometrical coverage and significantly increase detection sensitivity (by a factor of 30-40), thereby reducing the scanning times (30-40 times faster) or the patient’s radiation exposure. However, long AFOV scanners face two main challenges: greater depth-of-interaction (DOI) effects, which increase blurring and noise; and an increase in the volume required for the constituent crystals, which make up some 50% of the cost of the entire scanner. The use of shorter crystals can counteract both the DOI effects and the increased crystal volume (hence cost), but with a major loss of detection efficiency, defeating the original purpose. Another approach for reducing DOI effects is a double-ended read-out but this increases both cost and system complexity. Therefore, to achieve viable and affordable long AFOV scanners, a new scintillation material is required that would provide higher stopping power than LSO, with similar or better timing properties, and at a lower cost. These requirements can be met by a scintillator based on TlCl. This host has a comparable density (7.0 g/cm3 vs. 7.4 g/cm3 for LSO) and a much higher effective Z of 77 (vs. 65 to LSO.) When double doped with Be and I, it exhibits a fast donor-acceptor type luminescence with decay time <10 ns along with ultra-fast Cherenkov component (vs. 40 ns of LSO.) While the material’s light yield is low, its timing properties are excellent with better than 300 ps resolution FWHM when paired with LYSO, without any significant optimization. The only property where the material is deficient is its energy resolution (>15% at 511 keV, due to its low light yield). The key metric for TlCl is also its very low cost, in terms of raw materials as well as production – estimated 50% lower than LSO. In this project, we plan to optimize the doping content of TlCl to maximize its scintillation properties and achieve energy resolution of about 10% at 511 keV and timing resolution of 200 ps. In Phase II we will increase the volumes of produced material, develop cost reduction schemes, and produce and evaluate PET detection modules with the same performance goals.

项目概要 当前 PET 检测器技术需要具有快速响应、出色定时的闪烁 分辨率，高检测灵敏度，良好的能量分辨率，以及目前可接受的成本。 大多数 PET 系统使用 LSO (Lu2SiO5:Ce) 晶体或其类似物 LYSO，满足许多列出的要求 但LSO经过多年的发展，已经达到了其性能极限，特别是对于 目前正在开发的具有长轴向视场 (AFOV) 的扫描仪。 是显着增加几何覆盖范围并提高检测灵敏度（30-40 倍）， 减少扫描时间（快 30-40 倍）或患者的辐射暴露。 然而，长 AFOV 扫描仪面临两个主要挑战：更大的交互深度 (DOI) 效应， 增加模糊和噪音；以及增加组成晶体所需的体积，这使得 整个扫描仪的成本增加了约 50%，使用较短的晶体可以抵消 DOI 效应。 和增加的晶体体积（因此成本），但检测效率显着损失，击败了 减少 DOI 效应的另一种方法是双端读出，但这会增加。 因此，要实现可行且经济实惠的长 AFOV 扫描仪，需要一种新的技术。 需要闪烁材料提供比 LSO 更高的阻止能力，并具有相似或更好的定时 属性，并且成本更低。 基于 TlCl 的闪烁体可以满足这些要求。该主体具有相当的密度（7.0）。 g/cm3 vs. 7.4 g/cm3 (LSO) 和更高的有效 Z 为 77（vs. 65 LSO）。当双掺杂 Be 时 I，它表现出快速供体-受体型发光，衰减时间 <10 ns 以及超快切伦科夫 组件（相对于 LSO 的 40 ns。）虽然该材料的光输出较低，但其定时特性非常出色，具有更好的 与 LYSO 配合使用时，分辨率 FWHM 超过 300 ps，无需任何重大优化。 该材料的不足之处在于其能量分辨率（由于其光产量低，在 511 keV 时>15%）。 TlCl 的另一个优点是其原材料和生产成本非常低——估计比 LSO 低 50%。 在这个项目中，我们计划优化 TlCl 的掺杂含量，以最大限度地提高其闪烁性能和 在 511 keV 处实现约 10% 的能量分辨率，在第二阶段我们将提高 200 ps 的时间分辨率。 生产材料的数量，制定成本降低方案，并生产和评估 PET 检测 具有相同性能目标的模块。