Template matching method for γ-ray localization based on coded aperture imaging

Purpose: Gamma cameras based on coded aperture imaging are widely used to locate and identify radiation sources. The imaging quality is tightly related to the accuracy of γ-ray interaction location determining the projection data. Methods: We used the template matching (TM) method, combining the light response function to rebuild the interaction positions. Array and monolithic crystal detectors were employed in this study. We calculated the standard deviation of the reconstructed projection data and the reconstructed point source image’s contrast noise ratio (CNR) values for 60–1460 keV γ-rays. Results: 0.3-mm resolution was achieved for 60 keV γ-rays with simulation data. Compared to the classical center of gravity (CoG) method, the TM performs much better for both imaging systems with better noise immunity and energy extraction ability, achieving high reconstruction accuracy.