A high resolution and high sensitivity small animal SPECT system based on H8500

A compact multi-detector SPECT system for small animal (MicroSPECT) has been developed. The detector of MicroSPECT system is composed of a NaI scintillation crystal array and four H8500 flat panel position sensitive photon multiplier tubes(PS-PMT). The pixel size of the scintillation crystal array is 1.45mm×1.45mm and the total detection area is 103.75mm×103.75mm with 61×61 pixels. Four H8500 PS-PMTs are jointed together, coupling with the scintillation crystal array. Single pinhole and multi-pinhole collimators are used and special designed to satisfy the need of high spacial resolution or high sensitivity respectively. The DETECT2000 & MCNP Monte Carlo simulation programs were used for verifying the MicroSPECT system detector and pinhole collimator design. A high speed readout circuit was developed for the detectors. Each detector can achieve the counting rate at 300k/s. The results show that the scintillation crystal array has an effective area of 55×55 pixels and that the joint parts of the PS-PMTs are still available for detection. We aim that the MicroSPECT system can achieve 1mm spacial resolution or better.