This work is aimed at developing a novel simplified readout circuit for 2×2 H8500 multi-anode PSPMT array.The readout scheme is based on two-stage resistive networks with truncated center of gravity(TCOG) positioning method to optimize the detector performance.Test results showed that the readout circuit

which reduces the readout channels from 256 to 4

could well resolve the 1.2 mm crystal elements of the NaI(Tl) crystal array

with maximized effective field-of-view(FOV) of the detector

covering the entire active area of the detector.However

the optical coupling measures in the gap regions between the PSPMTs are necessary

so as to improve image distortion in the gap regions.The results indicate that our design is effective and can be adopted for high-resolution gamma camera with even larger FOV.