YSO coded aperture camera based on depth of interaction for location correction

Purpose Coded aperture imaging was a widely used imaging method for radiation sources. However, the traditional gamma camera based on two-dimensional projection information for coded aperture imaging ignored the influence of the interaction depth of particles and detectors on the projection information, which reduced the imaging quality of the camera to some extent. Therefore, a method of correcting the coded gamma camera based on the interaction depth of particles and detectors is proposed to improve the location accuracy of detectors.
Methods The camera developed in this work uses a 7 × 7 YSO crystal array coupled with two 7 × 7 Si-PM arrays. The crystal is evenly divided into 11 parts in the depth direction, with a voxel size of 3 × 3 × 3 mm³. The coded mask is a 13 × 13 array, which is a mosaic of two cycles of 7 × 7 modified uniformly redundant array mask. The depth resolution of the detector is obtained via the subsurface laser engraving dual-end readout method. After obtaining the three-dimensional position information of the interaction point the projection information obtained by the detector is layered, and the image is reconstructed. According to the spatial position information of the detector and the coded mask, the corresponding field of view of each layer of the detector is calculated, and the reconstructed image of each layer is amplified and superimposed according to the ratio of the field of view to obtain the reconstructed image combined with the depth information.
Results and conclusion According to Monte Carlo simulation and radiation source imaging experiment results, this method can effectively improve the positioning ability of the detector. For the experimental scenario mentioned in the paper, the location accuracy can be improved by up to 1.54°.