Resolution Recovery of a Static Multi-Pinhole SPECT System via PSF Deconvolution on Projection Domain

We evaluated a resolution recovery method for a static 11-pinhole SPECT system. Whereas a static SPECT system has an advantage of measuring a dynamic function of organs, the spatial resolution is significantly degraded when equipped with large pinholes. In this case, the widely used 7-rays method cannot sufficiently compensate the degradation. We have developed a deconvolution-based resolution recovery method, which approximates the system matrix with a single-ray projection through infinitesimal pinholes and point spread function (PSF) convolution. Although our previous study showed the effectiveness of the proposed method via a simulation, we assumed a shift-invariant PSF and a system with only three pinholes. As a natural consequence, the present study investigates the feasibility of our method with more realistic conditions. We apply our method to an 11-pinhole SPECT system with shift-variant PSFs. We perform an image-reconstruction simulation and demonstrate that the proposed method successfully reproduces detailed structures and outperforms the conventional method.