Performance evaluation of a multiplexing circuit combined with ASIC readout for cost-effective brain PET imaging

Objective.A key challenge in PET systems is collecting large amounts of data with the most accurate information-time, energy, and position-to produce high-resolution images while limiting the number of channels to reduce costs and improve data collection efficiency. The new ultra-high-performance brain (UHB) scanner under development aims to tackle this issue, using a semi-monolithic detector that combines pixelated arrays and monolithic designs, along with signal multiplexing techniques.Approach.We assessed the time, energy, and positioning performance of the multiplexing circuit (summing signals along rows and columns) and compared it to the standard readout, both using TOFPET2 ASIC.Main Results.While time resolution worsens by about 15%, energy and positioning resolution-more crucial in small diameter scanners-are unaffected by signal summation. Overall, a pair of detector modules (2 × 2 arrays each) features an energy resolution of 16.9 ± 1.3% and 405 ± 29 ps coincidence time resolution. Positioning accuracy-estimated using multilayer perceptron neural network-is 1.9 ±0.4 mm and 3.0 ±0.7 mm along the monolithic and depth-of-interaction direction, respectively.Significance.This study demonstrates that this channel reduction readout effectively maintains high performance while allowing for reduced costs and enhanced scalability.