Investigation of the effect of the scintillator material on the overall X-ray detection system performance by application of analytical models

The purpose of the present work was to model a modern X-ray detection system and to investigate the effect of the scintillator material on the detectorʹs output signal. The scintillators were used in the form of screens. The parameters investigated were the Modulation Transfer Function (MTF), the Detective Quantum Efficiency (DQE) and the Energy Absorption Efficiency (EAE). The results for some well-known scintillators (Y3Al5O12:Ce, Y2O3:Eu, ZnSCdS:Ag, Lu3Al5O7, CdWO4) are presented. Typical radiographic conditions were considered as input parameters. For simulation purposes, the intrinsic conversion efficiency (ηc), the total number of optical photons produced per incident X-ray (m0), the attenuation coefficients and other optical parameters of the scintillator materials, were taken as input data. The complete simulation procedure was performed in a specially designed Graphical User Interface (GUI). The results showed that the Y2O3:Eu scintillator presented similar behavior to that of ZnSCdS:Ag, exhibiting higher DQE at zero spatial frequencies. For higher frequencies, however, the DQE values of Lu3Al5O7 and CdWO4 prevailed.