IMAGE QUALITY IMPACT OF DIFFERENT PHOSPHOR ACTIVATOR MATERIALS IN Gd ₂O₂S BASED EPID SYSTEMS

Abstract

In this work, the effect of the scintillator on EPIDs signal transfer properties was examined. Modulation Transfer Function, Signal Power Spectrum and Light Output were assessed by analytical models while radiation incidence was estimated by Monte Carlo techniques. The frequency dependent Contrast Transfer Function (CTF) of a Gd2O2S:Tb based EPID system was experimentally determined by imaging the QC3 phantom in an iViewGT™ R3.4.1 MV Portal Imaging system for 6MV, 2MU and 400 DR irradiation conditions. In addition, an approximation of experimental MTF was determined. The Eu activator showed the highest light output per incident photon. A more detailed study should include the effect of scatter on MTF and the determination of the experimental MTF through CTF.