Fabrication and Evaluation of a Gd2O2S:Tb Phosphor Screen Film for Development of a CMOS-based X-ray Imaging Detector

Fabrication and Evaluation of a Gd2O2S:Tb Phosphor Screen Film for Development of a CMOS-based X-ray Imaging Detector

In this study, Gd2O2S:Tb phosphor screen films were fabricated by using a special particle-inbindersedimentation method. The phosphor particles used in this study were manufactured in twosizes, 2.5-μm and 5-μm. To evaluate luminescence efficiency and the spatial resolution according tothe thickness, we fabricated screen films with thicknesses of 120, 150, 170, and 210-μm. The spatialresolution of the fabricated films was assessed by using an edge method to measure the modulationtransfer function (MTF). From the experimental results, the spatial resolution of the mammographyexposures (low-energy X-ray quality) was better than that of dental radiography (high-energy X-rayquality). Also, with the same film thickness, the screen with 2.5-μm particles had better resolutionthan the screen with 5.0-μm particles, but it showed about 20% lower resolution than a commercialGd2O2S:Tb screen. In the evaluation of the results for the dependence of the spatial resolution onthe film’s thickness, the 120-μm-thick screen showed the highest resolution, which was similar tothat of a commercial screen.

In this study, Gd2O2S:Tb phosphor screen films were fabricated by using a special particle-inbindersedimentation method. The phosphor particles used in this study were manufactured in twosizes, 2.5-μm and 5-μm. To evaluate luminescence efficiency and the spatial resolution according tothe thickness, we fabricated screen films with thicknesses of 120, 150, 170, and 210-μm. The spatialresolution of the fabricated films was assessed by using an edge method to measure the modulationtransfer function (MTF). From the experimental results, the spatial resolution of the mammographyexposures (low-energy X-ray quality) was better than that of dental radiography (high-energy X-rayquality). Also, with the same film thickness, the screen with 2.5-μm particles had better resolutionthan the screen with 5.0-μm particles, but it showed about 20% lower resolution than a commercialGd2O2S:Tb screen. In the evaluation of the results for the dependence of the spatial resolution onthe film’s thickness, the 120-μm-thick screen showed the highest resolution, which was similar tothat of a commercial screen.