Performance Comparisons of Continuous Miniature Crystal Element (cMiCE) Detectors

Abstract

In this paper, we investigated the performance characteristics of continuous miniature crystal element (cMiCE) detectors. Versions with a 25 mm by 25 mm by 4 mm-thick LSO crystal and with a 50 mm by 50 mm by 8 mm-thick LYSO crystal were evaluated. Both detectors utilize a 64-channel flat panel photomultiplier tube (PMT). The intrinsic spatial resolution for the detectors was evaluated using Anger (i.e., simple centroid) positioning and a statistics based positioning (SBP) algorithm. We also compared the intrinsic spatial resolution for the 8-mm-thick LYSO crystal using different reflective materials (e.g., TFE Teflon, white paint, and a polymer mirror film) applied on the entrance surface of the crystal. The average energy resolution was 20% for the 4-mm-thick LSO crystal and ranged from 16% to 21%, depending upon reflective material, for the 8-mm-thick LYSO crystal. The average intrinsic spatial resolution for the 4-mm-thick crystal was 1.8-mm full width at half maximum (FWHM) for Anger positioning to within 3 mm of the crystal's edge and 1.14-mm FWHM for SBP to within 2 mm of the edge. The average intrinsic spatial resolution for the 8-mm-thick crystal was 2.2-mm FWHM for Anger positioning to within 8 mm of the crystal's edge and 1.3- to 1.5-mm FWHM (depending on reflective material used) for SBP to within 2 mm of the edge. Intrinsic spatial resolution is reported without correcting for point source size. The point spot flux had a FWHM of about 0.52 mm. The SBP algorithm resulted in significant improvement in intrinsic spatial resolution, linearity of positioning result, and effective field of view (FOV) for our cMiCE detector