Improved scintillators for time-of-flight positron emission tomography

用于飞行时间正电子发射断层扫描的改进闪烁体

• 批准号: 8449492
• 负责人: STEPHEN E. DERENZO
• 金额: $ 60.81万
• 依托单位: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8449492
• 关键词: Chest; Computers; Data; Databases; Detection; Development; Diagnostic Imaging; Discipline of Nuclear Medicine; Disease; Electronics; Elements; Equipment; Funding; Gamma Rays; Goals; Growth; Human body; Image; Indium; Isotopes; Laboratories; Low Dose Radiation; Lutetium; Measurement; Measures; Methods; Noise; Obesity; Patients; Photons; Physiologic pulse; Positioning Attribute; Positron; Positron-Emission Tomography; Powder Diffraction; Powder dose form; Radioactivity; Reaction Time; Research; Resolution; Roentgen Rays; Sampling; Shapes; Structure; System; Technology; Three-Dimensional Image; Time; Tissues; abstracting; analog; design; detector; improved; instrument; instrumentation; luminescence; public health relevance; radiation detector; response; theories

DESCRIPTION (provided by applicant): Improved Scintillators for Time-of-Flight Positron Emission Tomography Project Summary/Abstract We propose to significantly improve the diagnostic imaging capability of positron emission tomography by finding new scintillators with the gamma-ray stopping power of Lu2SiO5:Ce (LSO) and the luminosity, timing, and energy resolution of LaBr3:Ce. Compared with LSO, improving the luminosity from 30,000 photons/MeV to 60,000 photons/MeV and reducing the decay time from 40 ns to 20 ns will improve the timing resolution by a factor of two and the effective time-of-flight (TOF) sensitivity by a factor of two. This is because the variance of the statistical noise in the reconstructed image is reduced by the same factor as the timing resolution. Moreover, improving the energy resolution from 9% to 4% will reduce the background from tissue-scattered photons by about a factor of two. These advances in technology will significantly improve the detection of disease, especially in obese patients and for gated imaging of the thorax, and will increase the ability to use repeat imaging to study the effects of therapy on the disease. The proposed research will focus on Ce3+ and Pr3+ activated lutetium compounds because (1) of the known high-luminosity scintillators, only those activated with Ce3+ and Pr3+ are fast enough to be considered for TOF and 3D PET (2) of the trivalent elements in the periodic table that can be substituted with Ce3+ and Pr3+ to produce highly luminous scintillators (Y, La, Gd, and Lu), lutetium provides the highest atomic number and (3) no known high-luminosity scintillator contains an element heavier than lutetium. Thus, lutetium compounds have the highest promise of having both high luminosity and good stopping power for 511 keV annihilation photons. There are hundreds of dense lutetium compounds that have never been explored as gamma-ray scintillation detectors. We propose to use the high- throughput facilities developed at LBNL to synthesize doped candidate compounds in microcrystalline form, characterize their emissions under X-ray excitation, grow crystals of the best candidates, and measure the their energy and timing resolution. The crystal size and shape, and the photodetector and electronics will be similar to those used in a positron emission tomograph. Approximately 2,000 microcrystalline powder samples (of 200 different doped compounds) will be synthesized and characterized, and approximately 50 crystals of the best will be grown and measured. First-principles and empirical theory will be used to prioritize the candidate lists. LBNL is in a unique position to perform this research because of the recent creation of (1) the high-throughput scintillator discovery facility (funded by DHS) and (2) the crystal growth facility (funded by DOE and DHS). These contain 48 synthesis furnaces, an X-ray diffractometer, a pulsed X-ray system, an X-ray luminescence spectrometer, and 14 crystal growing furnaces of three different types. The measurement instruments have computer-controlled sample changers and automatically upload their data to an on-line database. Note that DHS does not fund the development of lutetium scintillators due to their inherent radioactivity and DOE no longer funds nuclear medicine research at the National Laboratories.

描述（由申请人提供）：改进的闪烁体的飞行时间正电子发射断层扫描项目摘要/摘要我们建议显着提高诊断成像能力的正电子发射断层扫描，通过寻找新的闪烁体的γ射线阻止能力的Lu2SiO5：Ce（LSO）和亮度，定时，和能量分辨率的LaBr3：Ce。与LSO相比，将亮度从30，000光子/MeV提高到60，000光子/MeV，并将衰减时间从40 ns减少到20 ns，将使时间分辨率提高两倍，有效飞行时间（TOF）灵敏度提高两倍。这是因为重构图像中的统计噪声的方差被减小了与定时分辨率相同的因子。此外，将能量分辨率从9%提高到4%将使来自组织散射光子的背景减少约两倍。这些技术进步将显著改善疾病检测，特别是肥胖患者和胸部门控成像，并将提高使用重复成像研究治疗对疾病影响的能力。所提出的研究将集中在Ce 3+和Pr 3+激活的镥化合物上，因为（1）在已知的高发光度发光剂中，只有用Ce 3+和Pr 3+激活的那些发光剂足够快以被考虑用于TOF和3D PET（2）周期表中的三价元素中的那些可以被Ce 3+和Pr 3+取代以产生高发光度发光剂（Y、La、Gd和Lu），镥提供最高的原子序数，并且（3）没有已知的高亮度闪烁体包含比镥更重的元素。因此，镥化合物具有最高的承诺，具有高的亮度和良好的阻止能力为511 keV的湮灭光子。有数百种致密的镥化合物从未被用作伽马射线闪烁探测器。我们建议使用LBNL开发的高通量设施来合成微晶形式的掺杂候选化合物，在X射线激发下表征它们的发射，生长最佳候选物的晶体，并测量它们的能量和定时分辨率。晶体的尺寸和形状，以及光电探测器和电子器件将与正电子发射断层扫描仪中使用的那些相似。将合成和表征大约2，000个微晶粉末样品（200种不同的掺杂化合物），并将生长和测量大约50个最好的晶体。第一原则和经验理论将用于确定候选人名单的优先次序。LBNL在进行这项研究方面处于独特的地位，因为最近创建了（1）高通量闪烁体发现设施（由DHS资助）和（2）晶体生长设施（由DOE和DHS资助）。其中包括48个合成炉、一个X射线衍射仪、一个脉冲X射线系统、一个X射线发光光谱仪和14个三种不同类型的晶体生长炉。测量仪器具有计算机控制的样品更换器，并自动将其数据上传到在线数据库。请注意，国土安全部不资助发展的镥消除器，由于其固有的放射性和能源部不再资助核医学研究在国家实验室。