Performance amelioration for small animal SPECT using optimized pinhole collimator and image correction technique
The aim of this study was to improve the performance of pinhole single photon emission computed tomography (SPECT) fabricated with a position sensitive photomultiplier tube using an optimized pinhole collimator and image correction technique. The center-of-rotation was aligned to prevent mechanical shift using a leveling-laser system. Based on the previous results of pinhole aperture simulation and optimization study, a pinhole collimator for the small animal SPECT was fabricated in the range of optimal pinhole diameter and channel height. Previously reported image correction technique of position mapping, energy calibration and flood correction procedures developed for array type scintillator was revised and applied to plate type crystal. Phantom and small animal studies were performed to investigate the system performance. Image corrections, center-of-rotation alignment, and collimator optimization were necessary to obtain high resolution and high quality SPECT images. The SPECT system ameliorated by this study could be utilized in small animal and molecular imaging studies required to provide high spatial resolution with moderate sensitivity.