Improvement of the Spatial Resolution With a Deconvolution Method for a Multi-pinhole SPECT System

We propose a method to improve the spatial resolution of an image for a static multi-pinhole single photon emission CT (SPECT) system. This SPECT system has a great advantage of measuring dynamic function of organs, which could not be performed by conventional systems. However, the image quality is very sensitive to the pinhole size of a collimator. In the case of a large pinhole, the widely applied 7-rays method could not sufficiently correct the image resolution. Hence, we propose a point spread function (PSF) deconvolution method for a multi-pinhole SPECT system. This method assumes a shift-variant PSF at each pixel of the detector, and performs PSF deconvolution on projection data. The feasibility of this method was investigated with a simulation. We assumed a static SPECT system with a multi-pinhole collimator, and projection images were obtained by a Monte Carlo method. The reconstructed images with our method had significantly higher spatial resolution and reproduced more detail structures compared with those of the 7-rays method. The images also showed higher PSNRs than the conventional ones. These results indicated the effectiveness of our proposed method.