Characterization of four readout circuits for an MR compatible, preclinical PET detector.

Characterization of four readout circuits for an MR compatible, preclinical PET detector.
Phys Med Biol. 2020 Apr 27;:
Authors: Selfridge AR, Cherry SR, Badawi RD
Abstract
We are building a high sensitivity preclinical PET/MRI insert using a highly multiplexed light sharing PET module. Each module incorporates four 19×19 arrays of 1×1×20 mm3 LYSO crystals with dual-ended DOI encoding readout, requiring thirty-two readout channels for positioning and eight channels for timing. These constraints necessitate compact, robust electronics for digitization. We have characterized four linearized time-over-threshold circuits based on these detector requirements. The four circuits allow for high channel density and can digitize signals from highly multiplexed light sharing detectors. Each circuit digitizes one channel of a multiplexed SiPM array, yielding a binary output that interfaces directly with an FPGA. Using the optimal circuit, we have characterized the performance of a pair of PET modules. The four circuits were characterized based on linearity of the 22Na photopeak positions and energy resolution at 511 keV, as well as separation of elements in a 10×10 array of 1.2 mm LYSO crystals coupled with a specular reflector. Practical measures of performance were comparable to those obtained with a DRS evaluation board, which served as a reference acquisition system. The ratio of the 22Na photopeak positions was 2.0 for each circuit and t...

Source: Physics in Medicine and Biology - April 26, 2020 Category: Physics Authors: Selfridge AR, Cherry SR, Badawi RD Tags: Phys Med Biol Source Type: research