Elimination of Central Artefacts of L-SPECT with Modular Partial Ring Detectors by Shifting Center of Scanning

Abstract: The Lightfield Single Photon Emission Computed Tomography (L-SPECT) system is developed to overcome some of the drawbacks in conventional SPECT by applying the idea of plenoptic imaging. This system displayed improved performance in terms of reduced information loss and scanning time when compared to the SPECT system which has a conventional collimator. The SPECT system is transformed into L-SPECT system by replacing the conventional collimators with micro-range multi-pinhole arrays. The field of view (FOV) of the L-SPECT system is enhanced by reshaping the detector head into ring-type by tiling small detector modules. The L-SPECT system with modular partial ring detectors (MPRD L-SPECT) exhibits cylindrical artefacts during volumetric reconstruction. Hence, here the work is focused to remove the cylindrical artefacts in the reconstruction of the examined objects by changing the scanning orbit. The enhancement is done such that the center of scanning of the L-SPECT system with MPRD L-SPECT is shifted at different values. The reconstruction quality of MPRD L-SPECT with and without center shifting is evaluated in terms of the Full Width at Half Maximum (FWHM) and Modulation Transfer Function (MTF). Moreover, the visual comparison is also examined. The results indicate that center shifting of MPRD L-SPECT overcomes the problem of the central artefact with improved FWHM. By increasing MPRD's scanning center shift gap, the spatial resolution can be further improved.