IMAGE QUALITY EVALUATION OF YVO4-EU PHOSPHOR SCREENS FOR USE IN X-RAYMEDICAL IMAGING DETECTORS

YVO4:Eu is a phosphor material emitting red light (621 nm) and providi ng excellent spectral compatibility with red sensitive optical detecto rs. However, it has never been used in medical X-ray imaging. In this study the imaging performance of six laboratory prepared YVO4:Eu test screens with coating weights from 30 to 140 mg/cm(2) was examined by e valuating the modulation transfer function (MTF), the X-ray luminescen ce efficiency (XLE), and the detective quantum efficiency (DQE). DQE w as evaluated by employing a method based on XLE and emission spectra m easurements. The 30 mg/cm(2) screen had a significantly higher MTF tha n thicker screens while its zero frequency DQE peak value was 0.27 at 30 kVp. Results obtained indicate that YVO4:Eu may be of value for use in X-ray imaging detectors. (C) 1998 Elsevier Science Ltd. All rights reserved.