Imaging performance and light emission efficiency of Lu2 SiO5:Ce (LSO:Ce) powder scintillator under X-ray mammographic conditions

Abstract

The aim of the present study was to measure the imaging transfer characteristics and the luminescence efficiency (XLE) of a Lu2SiO5:Ce (LSO:Ce) powder scintillator for use in X-ray mammography detectors. An LSO:Ce powder scintillating screen, with a coating thickness of 25 mg/cm2, was prepared in our laboratory. The imaging performance of the screen was assessed by experimental determination of the modulation transfer function (MTF) and the detective quantum efficiency (DQE) as well as single index image quality parameters such as noise equivalent pass band (Ne) and informational efficiency (n I). A theoretical model, describing radiation and light transfer, was fitted to experimental MTF values in order to estimate optical properties of the scintillator. Screen irradiation was performed under exposure conditions employed in mammographic applications (27 kVp, 63 mAs). MTF was determined by the square wave response function (SWRF) method. Results showed that LSO:Ce exhibits high MTF and DQE values, which are comparable to those of the commercially used Gd2O2S:Tb. Considering our image quality parameters and luminescence efficiency results as well as the fast response of the LSO:Ce scintillator screen (40 ns), this material can be considered for use in X-ray mammographic detectors.