Advances in coincidence time resolution for PET
Advances in coincidence time resolution for PET
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DOI：
10.1088/0031-9155/61/6/2255
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发表时间：
2016-03-21
影响因子：
3.5
通讯作者：
Levin, Craig S.
中科院分区：
文献类型：
--
作者：
Cates, Joshua W.;Levin, Craig S.
符合时间分辨率（CTR）是飞行时间（TOF）PET性能的重要参数，主要由所用闪烁晶体和光电探测器的特性决定。在过去的十年中，已经建立了稳定的LGSO：Ce（Lu1.8Gd0.2SiO5：Ce）的生产技术，其衰减时间从近似30-40 ns变化，并且衰减时间可以通过不同的铈浓度（0.025-0.075 mol%）来精确控制。这种材料对于TOF-PET是有希望的，因为与工业标准LSO：Ce和LYSO：Ce相比，它具有相似的光输出和对511 keV湮灭光子的等效阻止功率，并且在适当的Ce浓度下，衰减时间提高了30%以上。这项工作探讨了可实现的CTR与LGSO：Ce（0.025摩尔%）时，耦合到新的硅光电倍增管。晶体元件尺寸是实现快速定时的另一个重要参数。20 mm长度的晶体元件实现了更高的511 keV光子探测效率，但也引入了更高的闪烁光子渡越时间方差。3 mm长度的晶体对于PET是不实际的，但是具有减小的闪烁渡越时间扩展。测得2.9 x 2.9 x 3 mm（3）和2.9 x 2.9 x 20 mm（3）LGSO：Ce晶体对之间的CTR分别为80 +/- 4和122 +/- 4 ps FWHM。光产额和固有衰减时间的测量也提出了一个彻底的调查与LGSO：Ce（0.025摩尔%）的定时性能。
Coincidence time resolution (CTR), an important parameter for time-of-flight (TOF) PET performance, is determined mainly by properties of the scintillation crystal and photodetector used. Stable production techniques for LGSO:Ce (Lu1.8Gd0.2SiO5:Ce) with decay times varying from similar to 30-40 ns have been established over the past decade, and the decay time can be accurately controlled with varying cerium concentration (0.025-0.075 mol%). This material is promising for TOF-PET, as it has similar light output and equivalent stopping power for 511 keV annihilation photons compared to industry standard LSO:Ce and LYSO:Ce, and the decay time is improved by more than 30% with proper Ce concentration. This work investigates the achievable CTR with LGSO:Ce (0.025 mol%) when coupled to new silicon photomultipliers. Crystal element dimension is another important parameter for achieving fast timing. 20 mm length crystal elements achieve higher 511 keV photon detection efficiency, but also introduce higher scintillation photon transit time variance. 3 mm length crystals are not practical for PET, but have reduced scintillation transit time spread. The CTR between pairs of 2.9 x 2.9 x 3 mm(3) and 2.9 x 2.9 x 20 mm(3) LGSO:Ce crystals was measured to be 80 +/- 4 and 122 +/- 4 ps FWHM, respectively. Measurements of light yield and intrinsic decay time are also presented for a thorough investigation into the timing performance with LGSO:Ce (0.025 mol%).