Study on analytical system matrix constructions for a stationary multipinhole SPECT system

A stationary multi-pinhole SPECT system without rotating the detectors is useful in molecular imaging of pre-clinical and dynamic study. In previous study, a voxel-driven method (RVM) for system matrix construction was used to calculate the system model for a static three-head multi-pinhole system. For reducing the artifacts caused by limited sampling angle, both sub-ray and sub-mask models in constructing the multipinhole system matrix were applied in the cost of computation time. In order to improve the computational efficiency, we applied a new projection model method (NPM) proposed previously to simplify the system matrix calculation while retaining the accuracy. Digital simulation data from GATE was used to evaluate the performance of the NPM in comparison with two other methods (RVM and conventional ray-driven method). The preliminary results show that NPM can generate more accurate projection data and reconstruction while with much less computation time as compared to RVM.