Abstract
New high-resolution 12″ x-ray image intensifier (I. I.) has been developed exclusively for use with a 2048×2048-matrix real-time II-TV digital radiography (DR) system. The basic imaging properties of a 100-mm roll-film system and DR system using this I. I. were examined to determine the effects of physical parameters on the quality of the GI-tract images, and also to explore the clinical usefulness of the system. We found that the resolution of the 100-mm roll-film system at 7″ I. I. mode is superior to that of screen-film system. The incident exposures for these systems with 12″ I. I. mode were approximately 1/12 of that for the screen-film system (HR4/HRS). The small x-ray focus of 0.2mm can be employed with the I. I. system, so the effect of geometric unsharpness can be reduced. Therefore, it was possible to apply the magnification technique. The ROC analysis indicates that the image obtained with the DR system at 7″ I. I. mode under the condition with less than half exposure relative to the screen-film system provides similar detectability to the image with the screen-film system (HRS/HR6). It was found that these 100-mm roll-film and DR systems can be applied not only to the mass screening but to the accurate GI-tract examinations.
