Energy response correction for imaging detectors based on monolithic crystals

Abstract: The energy response of an imaging detector based on a monolithic crystal is highly dependent on the position of the gamma ray interaction, which leads to a spectral drift of the imaging detector, known as the spectral drift related to incident position. It deteriorates the energy resolution of the detector and affects the selection of the energy window for imaging, resulting in artefacts in the reconstructed image. Thus, a energy response correction method is proposed to improve the positional consistency of the detector energy response. In both simulation and physical experiments, the method improved the full-energy peak consistency of the monolithic crystal detector, which results in improved energy resolution of the detector, more accurate selection of the energy window, and imaging quality. Especially, in physical experiments, the method converges the peak sites of 365keV energy at each location, which reduced the half-height width of characteristic peak (@365 keV) from 53 to 38 channels, improved the energy resolution by 28.3%, transformed the incomplete mask projection into a complete mask projection, and the signal-to-noise ratio increased from 2.38 to 5.37.