The Research On Small Animal Single Photon Emission Computed Tomography Imaging System

The MicroSPECT system is a high resolution small animal SPECT system withpin-hole collimetor. The detector consists four H8500 PS-PMTs and one NaI scin-tillation crystal array. The pixel size of the crystal array is 1.65mm and the e?ectivedetection matrix size is 54×54. The DETECT2000 Monte Carlo simulation programverified the MicroSPECT system detector design. The results show that the joint partsof photon multiplier tubes are still available for detection. The pin-hole parameters arealso calculated by Monte Carlo method.A compact and accurate readout system has been developed for MicroSPECT. Us-ing resistive matrix and charge division circuit, The 256 anodes from the four H8500sare reduced to 4 signals. The gain di?erences are normalized between anodes inH8500. The readout system can achieve the counting rate at 500k/s with the precisionat 12bit for each detector and the digital part can support 4 detectors'data transporta-tion.The computer graphic methods are used in detetor correction. The 2D-map iscalculated by a Watershed method and an auto-numbering method. We do the normal-ization correction, decay correction and energy spectrum correction after that. And theposition correcitons of the whole system are based on lines specially designed modelimaging.The whole system was verified by a serial model imaging and mouse MDP imag-ing. The resolution of the system is between 1.6mm which measures up the designobject. We can base the system for the further investigation of small animal SPECTimaging.