Lu-Free Scintillators for PET

用于 PET 的无 Lu 闪烁体

• 批准号: 9126643
• 负责人: KANAI SHAH
• 金额: $ 65.95万
• 依托单位: RADIATION MONITORING DEVICES, INC.
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-09 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9126643
• 关键词: Adsorption; Aluminum; Alzheimer' s Disease; Area; Biological; Biological Process; Body Image; Caliber; Carbon Isotopes; Ceramics; Cerium; China; Clinical; Country; Craniocerebral Trauma; Development; Diagnosis; Disease; Drops; Economics; Evaluation; Fluorine; Functional Imaging; Future; Gadolinium; Gallium; Goals; Growth; Health; Healthcare; Image; Imaging Techniques; Ions; Japanese Population; Label; Life; Light; Lutetium; Malignant Neoplasms; Marketing; Measures; Medical Imaging; Minerals; Mining; Nitrogen; Oils; Optics; Output; Oxides; Oxygen; Performance; Phase; Photons; Physics; Policies; Politics; Positron; Positron-Emission Tomography; Powder dose form; Preparation; Price; Procedures; Process; Production; Property; Radioactivity; Rare Earth Metals; Relative (related person); Reporting; Research; Resolution; Route; Sampling; Site; Source; Stroke; Symptoms; System; Technology; Tennessee; Testing; Thick; Time; Universities; analog; base; cost; density; design; detector; gadolinium oxide; improved; in vivo; interest; novel; operation; response; scale up

DESCRIPTION (provided by applicant): Positron Emission Tomography (PET) is a functional imaging technique with the potential to quantify the rates of biological processes in vivo. PET imaging can provide diagnosis for symptoms of diseases such as cancer, Alzheimer's disease, head trauma, and stroke. However, to allow exploitation of the full potential of PET, there is urgent need for both improvement in the performance of PET systems and reduction in their cost. Both of these factors are strongly influenced by the available detector technology. Scintillation crystals are currently used as detectors in PET. Requirements for the scintillation crystals used in PET include fast response, high sensitivity, high light output, high energy and timing resolution, and low cost. At present, most PET systems use crystals of Lu2SiO5:Ce (LSO) or its derivative LYSO, which satisfy most of the requirements listed above. Nevertheless, issues remain with the cost and availability of lutetium that must be considered with respect to the future production of scintillators for PET and when developing potential new scintillators. There are several diverse factors that influence the cost and availability of the lutetium oxide material used in LSO/LYSO crystal growth for PET, but perhaps the most fundamental is geological. The main mineral sources for lutetium are xenotime (LuPO4) and ion adsorption clays, both of which are predominately found in China. There is very little production of lutetium from any other country. It is difficult to make long term predictions of China's strategy with respect to rare earth exports, but recent years have seen ever increasing production controls and higher tariffs on exported rare earth materials in general. On the other hand, gadolinium, also an attractive rare earth element for scintillators, can be found in several different minerals including monazite, which exist in various parts of the world, thus making it's availability less dependent on the economy and politics of a single nation. Gadolinium offers some additional advantages compared to lutetium. Its natural abundance in the earth's crust is an order of magnitude greater than lutetium, and its larger ionic size makes it considerably easier to separate and purify relative to the smaller rare earth ions such as lutetium. These two fundamental factors combine to offer the potential of significantly lower cost for the same level of purity (by a factor of ~15). The larger ionic size also means that it provides a substitutional site for cerium that is better matched to the relatively large size of the cerium ion. Finally, unlke lutetium, gadolinium has no natural radioactivity, an additional benefit. In view of the serious concerns about availability and cost of Lu, the goal of the proposed project is to investigate novel Lu-free scintillators for PET imaging. The idea is to achieve reduction in cost, maintain a predictable supply of raw materials, and exceed the performance of LSO. In view of the advantages cited above, we plan to design the new scintillator based on Gd3+ as the rare earth ion and incorporating it into a cubic garnet matrix.

描述（由申请人提供）：正电子发射断层扫描（PET）是一种功能成像技术，具有量化体内生物过程速率的潜力。 PET 成像可以诊断癌症、阿尔茨海默病、头部外伤和中风等疾病的症状。然而，为了充分发挥 PET 的潜力，迫切需要提高 PET 系统的性能并降低其成本。这两个因素都受到可用探测器技术的强烈影响。目前，闪烁晶体被用作 PET 中的探测器。 PET中使用的闪烁晶体的要求包括快速响应、高灵敏度、高光输出、高能量和时间分辨率以及低成本。目前，大多数PET系统使用Lu2SiO5:Ce（LSO）或其衍生物LYSO晶体，满足上述大部分要求。然而，镥的成本和可用性仍然存在问题，在未来生产 PET 闪烁体以及开发潜在的新型闪烁体时必须考虑这些问题。有多种不同的因素会影响 PET 的 LSO/LYSO 晶体生长中使用的氧化镥材料的成本和可用性，但也许最基本的是地质因素。镥的主要矿物来源是磷钇矿（LuPO4）和离子吸附粘土，两者主要产于中国。其他国家的镥产量很少。很难对中国稀土出口战略做出长期预测，但近年来生产控制不断加强，稀土出口关税普遍提高。另一方面，钆也是一种对闪烁体有吸引力的稀土元素，可以在包括独居石在内的几种不同矿物中找到，这些矿物存在于世界各地，从而使其可用性较少依赖于单个国家的经济和政治。与镥相比，钆具有一些额外的优势。它在地壳中的自然丰度比镥大一个数量级，并且其较大的离子尺寸使其相对于较小的稀土离子（例如镥）更容易分离和纯化。这两个基本因素相结合，可以在相同纯度水平下显着降低成本（约 15 倍）。较大的离子尺寸还意味着它为铈提供了一个与相对较大尺寸的铈离子更好匹配的取代位点。最后，与镥不同，钆没有天然放射性，这是一个额外的好处。鉴于对 Lu 的可用性和成本的严重担忧，该项目的目标是研究用于 PET 成像的新型无 Lu 闪烁体。这个想法是为了降低成本、维持可预测的原材料供应并超越 LSO 的性能。鉴于上述优点，我们计划设计一种以Gd3+为稀土离子并将其纳入立方石榴石基体的新型闪烁体。