A Novel Compton Camera with an Annular Absorber for Enhancing the Imaging Efficiency in Regions Immediately Ahead: A Simulation Study

This paper proposed a novel Compton camera with an annular absorber which improved the imaging efficiency of immediate regions. We compared the sensitivity and angular resolution of such a Compton camera with those of a typical Compton camera with two planar detectors. The scatterers of the typical Compton camera consisted of 8×8 GAGG crystals, with each measuring 1 cm×1 cm×0.5 cm and the absorber of the same system was composed of 8×8 GAGG crystals, each of which measures 1 cm×1 cm×1 cm. The scatterers of the novel Compton camera was the same as the typical one, but the absorber of the novel Compton camera consisted of sixty-four GAGG crystals, each also measuring 1 cm×1 cm×1 cm, which were arranged in an annular shape with an inner radius of ~5.15 cm and an outer radius of ~7.39 cm. A point
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Na source was placed 100 cm away from the center of the scatter and subsequently imaged by the two cameras. The efficiency and angular resolution of the two cameras and compared with each other were calculated by changing the distance between the two layers of the detectors. The novel Compton camera significantly enhanced the detection efficiency while maintaining a comparable angular resolution, and the enhancement depended on the distance between the scatterer and absorber. The enhancement was over 50% when the distance was 13 cm.