Performance study of monolithic crystal detector based on neighboring crystal light sharing with dual-ended readout.

Abstract

Objective.The monolithic crystal detector has attracted attention due to its high detection efficiency and intrinsic depth of interaction (DOI) resolution. However, the inherent edge effects degrade the performance at the boundaries of the detector, resulting in reduced positioning accuracy. To address this issue, this paper proposes a dual-ended readout positron emission tomography (PET) detector based on neighboring monolithic crystal light sharing. By combining the advantages of light sharing and dual-ended readout, the spatial resolution at the edges of the monolithic crystal detector is improved.Approach.Four LYSO crystals measuring 40∗40∗20 mm³were utilized in this paper. A high-refractive-index optical adhesive was employed to bond the polished sides of the four crystals into a cohesive unit. In the two-dimensional plane positioning of the detector, the centre of gravity (COG) method is employed using a threshold reduction and a combined response calculation of the neighboring crystal light sharing.Main results.The results indicate that the dual-ended readout detector based on light sharing achieves spatial resolution results in the light-sharing area that are comparable to those in the central area, yielding a spatial resolution of 0.76 mm on the X=0 plane of a 20 mm thick crystal detector, significantly mitigating the edge effects of the monolithic crystal detector. Furthermore, the single-ended readout detector utilizing the light sharing technique has achieved a spatial resolution of 0.99 mm across the entire detector plane.Significance.The dual-ended readout detector utilizing light sharing among neighboring crystals effectively addresses the edge effect issue encountered in monolithic crystal detectors, thereby achieving high spatial resolution in thick crystals. This innovative approach presents an advantageous detector scheme for the advancement of high-sensitivity, high-spatial-resolution small animal PET.