Nanocrystalline Phosphors for Medical Imaging Applications

描述(申请人提供)：将开发基于纳米晶体量子点(QD)的新型高性能X射线荧光屏，应用于蛋白质结晶学、数字放射照相和乳房X光照相应用，以及许多其他重要的成像和照明应用。这个项目的目标是最大限度地提高X射线转换效率、空间分辨率和时间响应，从而最大限度地减少余辉。纳米复合荧光屏将在最先进的晶体电荷耦合器件探测器上进行测试，并与“标准”的微晶锌硒：铜、氯和Gd2O2S：Tb荧光屏进行比较。虽然由微米级荧光粉制成的荧光屏是高效、明亮的X射线转换器，但它们的大颗粒会产生大量的散射，这限制了它们的空间分辨率。初步的理论和实验研究表明，透明聚合物基屏中的量子点荧光粉比微米尺寸的荧光粉显示出更高的空间分辨率。此外，它们具有皮秒到纳秒的衰减时间和低余辉特性，将确保响应时间比现有荧光粉快几个数量级。此外，QD荧光粉可以由高Z材料制成，以增加X射线的吸收，并对其光谱特性进行调整，以匹配CCD传感器的光谱灵敏度。具体地说，在第一阶段，我们将制备量子点荧光粉和相关的筛选技术，并量化它们的X射线光致发光性能。如果我们能证明纳米晶体荧光粉在空间分辨率和时间分辨率方面明显优于现有的微米级晶体荧光粉，那么第一阶段的成功将得到证明。在第二阶段，我们将开发合成大量高质量纳米晶体的技术，并优化蛋白质结晶学和医学成像CCD探测器的大屏幕特性。基于QD的X射线转换膜将在数字射线照相、结晶学、乳房X光照相和各种其他生物医学成像应用中有重要应用，提高它们对美国国立卫生研究院以及整个分子生物学和医学界的价值。关键词：X射线荧光粉、纳米荧光粉、纳米晶体、量子点、蛋白质结晶学、数字射线照相、乳房X光照相、生物医学成像。与公众健康相关：拟议的纳米磷光材料将在数字射线照相、结晶学和各种医学成像应用中有重要应用，提高其对美国国立卫生研究院以及整个分子生物学和医学界的价值。

DESCRIPTION (provided by applicant): A new class of high-performance X-ray phosphor screens will be developed based on nanocrystal quantum dots (QDs), with applications to protein crystallography, digital radiography and mammography applications, as well as a host of other important imaging and lighting applications. The goal in this project is to maximize X-ray conversion efficiency, spatial resolution, and time response, which will minimize afterglow. Nano-composite phosphor screens will be tested in state-of- the-art crystallographic CCD detectors, and compared with "standard" micro-crystalline ZnSe:Cu,Cl and Gd2O2S:Tb phosphor screens. Although phosphor screens made from micron-sized phosphors are efficient, bright X-ray converters, their large particle size produces a great deal of scatter, which limits their spatial resolution. Preliminary theoretical and experimental studies show that quantum dot phosphors in a transparent polymer-matrix screen exhibit significantly higher spatial resolution than micron-sized phosphor particles. In addition, their pico- to nano-seconds decay times and low afterglow characteristics will ensure response times orders of magnitude faster than existing phosphors. Moreover, QD phosphors can be made from high-Z materials to increase X-ray absorption and their spectral characteristic tuned to match the spectral sensitivity of CCD sensors. Specifically in Phase I, we will prepare QD phosphors and related screening techniques, and quantify their X-ray photoluminescence performance. Success in Phase I will be proven if we can show that nanometer-sized crystalline phosphors are significantly better than existing micron-sized crystalline phosphors, in terms of spatial resolution and time resolution. In Phase II, we will develop the techniques to synthesize large quantities of high quality nanocrystals, and optimize large screen characteristics for protein crystallography and medical imaging CCD detectors. QD-based X-ray converting films will have significant applications in digital radiography, crystallography, mammography, and various other biomedical imaging applications, enhancing their value to the NIH and to the molecular biology and medical communities as a whole. Key Words: Xray phosphor, nano-phosphor, nanocrystals, quantum dots, protein crystallography, digital radiography, mammography, biomedical imaging. PUBLIC HEALTH RELEVANCE: The proposed nanocrystalline phosphor materials will have significant applications in digital radiography, crystallography, and various medical imaging applications, enhancing its value to the NIH and to the molecular biology and medical communities as a whole.