Modulation transfer function of amorphous selenium digital x-ray detectors
Authors: Yuan Fang, Nicholas Allec, Ling Guo and Karim Karim.
Abstract:
We evaluate the modulation transfer function (MTF) of amorphous selenium (a-Se) digital x-ray detectors. This study includes the effects of generation and reabsorption of characteristic x-rays, which can significantly degrade the
detector MTF. Monte Carlo (MC) methods are used for simulation of spatial dose distribution, and the detector MTF is computed by Henkel Transform. We consider mammography and chest radiography x-ray energies and detector thicknesses in this study. Incident photon energies of 12 keV, 13 keV, 50 keV and 100 keV are simulated for 150 μm, 300 μm, and 1 mm thick a-Se x-ray detectors. Significant MTF degradation is observed at incident photon energies higher than the a-Se K-edge, due to generation and reabsorption of characteristic x-rays.