Intensive study for realization of the next-generation brain PET system with high sensitivity, high spatial resolution and high speed

对实现高灵敏度、高空间分辨率、高速度的下一代PET系统的关键技术进行了研究。我们开发了直径为100 mm的大尺寸GSO单晶的生长技术。在我们的相互作用深度(DOI)探测器中，我们可以通过在晶体元素之间插入反射器来控制闪烁光子的行为。相互作用的晶体的确定是在二维直方图上执行的，该二维直方图利用来自光耦合到晶体阵列的PS-PMT的输出信号通过愤怒类型定位算术计算来映射。一种高性能的脑DOI-PET扫描仪，JPET-D4，已经在NIRS开发出来。这种扫描仪的设计不仅是为了实现高空间分辨率，而且使用四层DOI探测器来实现高灵敏度。该扫描仪有5个探测器环，环直径为390 mm，每个探测器环由24个DOI探测器组成。每个DOI探测器由1,024个GSO晶体组成，这些晶体排列成四层16×16阵列，与52 mm方形256通道位置灵敏光电倍增管(FP-PMT)耦合。晶体元素为2.9×2.9×7.5 mm^3。层1、层2和层3、4的晶体分别为掺Ce 0.5%和1.5%的GSO。整个视场中心的灵敏度为112kCPS/MBq，空间分辨率小于3 mm。

Key technologies to realize the next-generation PET system with high sensitivity, high spatial resolution and high speed has been studied. We have developed growing technology of large gadolinium silicate (GSO) single crystals with a diameter of 100 mm. In our depth-of-interaction (DOI) detector, we can control the behavior of scintillation photons by inserting the reflector between crystal elements. The determination of the crystal of the interaction is performed on a two-dimensional histogram mapped by Anger-type positioning arithmetic calculation with output signals from PS-PMT optically coupled to the crystal array. A high-performance brain DOI-PET scanner, jPET-D4, has been developed at NIRS. This scanner was designed to achieve not only high spatial resolution but also high sensitivity using four-layered DOI detectors. The scanner has five detector rings with the ring diameter of 390mm and each detector ring consists of 24 DOI detectors. Each DOI detector consists of 1,024 GSO crystals, which are arranged in four layers of 16 x 16 arrays, coupled to a 52 mm square 256ch position sensitive PMT (FP-PMT). The crystal elements are 2.9 x 2.9 x 7.5 mm^3. The crystals of layer-1, 2 and layer-3, 4 are GSO doped with 0.5 mol% and 1.5 mol% Ce, respectively. The sensitivity at the center of FOV is 112 kcps/MBq and spatial resolution is less than 3 mm all over the FOV.