Fluorozirconate-based nanophase glass ceramics for high-resolution medical X-ray imaging

Abstract

Two-dimensional indirect digital X-ray detectors use either a storage phosphor or a scintillator as an imaging plate. A storage phosphor forms a latent X-ray image, which is subsequently read as a visible image by a photostimulated luminescence method. A scintillator produces a visible image during X-ray illumination. Commercial storage phosphor plates have a relatively poor spatial resolution due to light scattering in the readout process by the grains of phosphor material that are embedded in the plates. To improve the image resolution of storage phosphors and apply them to high-resolution mammography, we are developing image plates of Eu 2+-doped fluorozirconate-based nanophase glass ceramics. X-ray imaging tests show that the resolution of these storage phosphor plates exceeds that of commercial ones by about a factor of 10. By using appropriate thermal-processing conditions, we are able to make transparent nanophase glass ceramic scintillators based on the same materials. The imaging tests show that these scintillators have high a resolution and high efficiency compared to a single-crystal CdWO 4 scintillator. These results demonstrate that fluoroziconate-based nanophase glass ceramics are good candidates for medical X-ray imaging, such as high-resolution mammography.