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.

项目摘要 目前PET中的探测器技术要求闪烁具有快速响应、良好的定时 高分辨率、高检测灵敏度、良好的能量分辨率，以及最后但并非最不重要的可接受成本。目前， 大多数聚酯系统使用LSO(Lu2SiO5：Ce)晶体或其类似的Lyso，这满足了许多列出的 要求。但LSO经过多年的发展，已经达到了它的性能极限，特别是对于 目前正在开发的具有长轴视场(AFOV)的扫描仪。这些扫描仪的目标是 是增加几何覆盖率并显著提高检测灵敏度(提高30-40倍)， 从而减少扫描时间(快30-40倍)或患者的辐射暴露。 然而，长距离AFOV扫描仪面临两个主要挑战：更大的交互深度(DOI)效应，这 增加模糊和噪声；以及增加组成晶体所需的体积，这使得 增加了整个扫描仪成本的50%左右。使用较短的晶体可以抵消DOI效应 以及增加的晶体体积(因此成本)，但在检测效率的重大损失的情况下，击败了 最初的目的。另一种减少DOI影响的方法是双端读出，但这会增加 成本和系统复杂性。因此，为了实现可行和负担得起的长AFOV扫描仪，一种新的 闪烁材料需要提供比LSO更强的阻止能力，并且具有类似或更好的定时 物业，而且成本更低。 基于TlCl的闪烁体可以满足这些要求。此主机的密度与之相当(7.0 G/cm3，而LSO为7.4 g/cm3)，有效Z值高得多，为77(LSO为65)。当双掺Be时 I，它表现出快速的施主-受主类型的发光，衰减时间为10 ns，同时具有超快的切伦科夫发光 组件(与LSO的40 ns相比。)虽然这种材料的光产额很低，但它的定时性能很好， 当与lyso配对时，分辨率超过300ps的半高宽，无需任何重大优化。唯一的财产 材料的不足之处在于其能量分辨率(由于其低的光产额，在511keV时的分辨率为15%)。关键指标 对于TlCl来说，就原材料和生产而言，它的成本也非常低--估计比LSO低50%。 在这个项目中，我们计划优化TlCl的掺杂含量，以最大化其闪烁性能和 在511keV和200ps的时间分辨率下，能量分辨率约为10%。在第二阶段，我们将增加 生产材料的数量，制定降低成本的方案，生产和评估PET检测 具有相同性能目标的模块。