X-ray imaging resolution of phosphor screens prepared with different grains size and shape of granular Lu2O3:Eu

Abstract

The influence of the grain shape and size on spatial resolution (ranging from nano to micro scale) of various Lu2O3:Eu phosphor screens was investigated. All screens were prepared using the sedimentation method. Three screens were prepared with spherical grains and sizes 50 nm, 200 nm and 5 μm, whilst two screens with rod-like shape grains and sizes 500 nm and 1-8 μm. All screens were coupled to a high resolution CMOS digital imaging sensor (Remote RadEye HR) consisting of 1200 x 1600 pixels with 22.5 μm pixel pitch. Experiments were performed under radiographic conditions, using 70 kVp tube voltage and 63 mAs tube load. Spatial resolution was assessed utilizing the Modulation Transfer Function (MTF). It was found that the influence of the grains shape on imaging performance was more crucial than the grain size. The rod-like grains showed very poor spatial resolution. The influence of grains size between 50 nm 200 nm and 5 μm was negligible on MTF values.