Performance evaluation of microPET: a high-resolution lutetium oxyorthosilicate PET scanner for animal imaging.
Performance evaluation of microPET: a high-resolution lutetium oxyorthosilicate PET scanner for animal imaging.
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发表时间：
1999-07
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通讯作者：
A. Chatziioannou;S. Cherry;Y. Shao;R. Silverman;K. Meadors;T. Farquhar;Marjan Pedarsani;M. Phelps
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作者：
A. Chatziioannou;S. Cherry;Y. Shao;R. Silverman;K. Meadors;T. Farquhar;Marjan Pedarsani;M. Phelps
一种新的专用PET扫描仪，microPET，是在加州大学，洛杉矶设计和开发的，用于成像小实验室动物。目标是提供一个紧凑的系统，具有上级空间分辨率，成本仅为临床PET扫描仪的一小部分。方法该系统采用光纤读出的单独切割的硅酸氧镥（LSO）晶体，以达到高的空间分辨率。每个microPET探测器由一个8 x 8阵列的2 x 2 x 10 mm LSO闪烁晶体组成，通过光纤耦合到64通道光电倍增管。断层扫描仪由30个探测器组成，呈连续环形，直径为17.2 cm，轴向和轴向视野（FOV）分别为11.25 cm和1.8 cm。该系统有八个晶体环，没有面间隔膜。它只在三维模式下运行，并有一个电子控制的床，能够以300微米的半径摆动。我们从空间、能量和时间分辨率以及灵敏度和计数率性能方面描述了断层扫描仪的性能。我们还说明了它的整体成像性能与幻影和动物研究，证明了该设备的潜在应用，生物医学研究。结果三维滤波反投影重建图像在FOV中心（CFOV）的空间分辨率为1.8 mm，在轴向FOV中心5 cm处的空间分辨率<2.5 mm。系统的体积分辨率<8微升。用0.74 MBq（20 microCi）~（68）Ge点源在CFOV下测得的绝对系统灵敏度为5.62 Hz/kBq。用直径为6.4 cm的圆柱体跨越FOV中心56%获得的最大噪声等效计数率为10 kcps，而对于250-650 keV的能量窗口和相同直径的圆柱体，在CFOV处的散射分数为37%。结论：这是第一台使用新型闪烁体LSO的PET扫描仪，并采用了新型探测器设计，以实现高体积空间分辨率。该原型系统的成像特性（分辨率、灵敏度、计数率性能和散射分数）的组合为PET动物模型的研究开辟了新的可能性。
UNLABELLED A new dedicated PET scanner, microPET, was designed and developed at the University of California, Los Angeles, for imaging small laboratory animals. The goal was to provide a compact system with superior spatial resolution at a fraction of the cost of a clinical PET scanner. METHODS The system uses fiberoptic readout of individually cut lutetium oxyorthosilicate (LSO) crystals to achieve high spatial resolution. Each microPET detector consists of an 8 x 8 array of 2 x 2 x 10-mm LSO scintillation crystals that are coupled to a 64-channel photomultiplier tube by optical fibers. The tomograph consists of 30 detectors in a continuous ring with a 17.2-cm diameter and fields of view (FOVs) of 11.25 cm in the transaxial direction and 1.8 cm in the axial direction. The system has eight crystal rings and no interplane septa. It operates exclusively in the three-dimensional mode and has an electronically controlled bed that is capable of wobbling with a radius of 300 microm. We describe the performance of the tomograph in terms of its spatial, energy and timing resolution, as well as its sensitivity and counting-rate performance. We also illustrate its overall imaging performance with phantom and animal studies that demonstrate the potential applications of this device to biomedical research. RESULTS Images reconstructed with three-dimensional filtered backprojection show a spatial resolution of 1.8 mm at the center of the FOV (CFOV), which remains <2.5 mm for the central 5 cm of the transaxial FOV. The resulting volumetric resolution of the system is <8 microL. The absolute system sensitivity measured with a 0.74 MBq (20 microCi) 68Ge point source at the CFOV is 5.62 Hz/kBq. The maximum noise equivalent counting rate obtained with a 6.4-cm diameter cylinder spanning the central 56% of the FOV is 10 kcps, whereas the scatter fraction is 37% at the CFOV for an energy window of 250-650 keV and the same diameter cylinder. CONCLUSION This is the first PET scanner to use the new scintillator LSO and uses a novel detector design to achieve high volumetric spatial resolution. The combination of imaging characteristics of this prototype system (resolution, sensitivity, counting-rate performance and scatter fraction) opens up new possibilities in the study of animal models with PET.