Modeling and Simulation of Charge-Induced Signals in Photon-Counting CZT Detectors for Medical Imaging Applications

TL;DR

This paper presents a computational model for simulating charge signals in CZT photon-counting detectors, accounting for crystal defects, to improve medical imaging accuracy.

Contribution

It introduces an efficient simulator that models spatial variability in CZT detectors, serving as a digital twin to enhance performance and compensate for impurities.

Findings

RMSE in signal simulation below 0.70%

Simulator accurately replicates detector signals

Potential to mitigate effects of crystal defects

Abstract

Photon-counting detectors based on CZT are essential in nuclear medical imaging, particularly for SPECT applications. Although CZT detectors are known for their precise energy resolution, defects within the CZT crystals significantly impact their performance. These defects result in inhomogeneous material properties throughout the bulk of the detector. The present work introduces an efficient computational model that simulates the operation of semiconductor detectors, accounting for the spatial variability of the crystal properties. Our simulator reproduces the charge-induced pulse signals generated after the X/gamma-rays interact with the detector. The performance evaluation of the model shows an RMSE in the signal below 0.70%. Our simulator can function as a digital twin to accurately replicate the operation of actual detectors. Thus, it can be used to mitigate and compensate for adverse effects arising from crystal impurities.