Innovative radiographic system to improve the sharpness of radiographs: could a phase-shift effect contribute to improved image-quality for plain computed radiographs for general use?

PURPOSE: The aim of this study was to determine whether a high-resolution digital radiography system that was originally developed for mammography could be used for general radiographic purposes by means of a phantom test. MATERIALS AND METHODS: This system includes an X-ray tube with a smaller focal point than is generally used for general radiography, and a computed radiography (CR) system to provide the highest spatial resolution. The imaging object and CR plate are intentionally separated to capture an edge-enhancing effect that is the result of a phase-shift (phase contrast) of the X-rays. RESULTS: This system showed greater sharpness and spatial resolution, as well as an equal level of contrast resolution compared to a conventional X-ray system. The image sharpness in this system appears to be at least partially attributable to an edge-enhancing effect produced by the phase-contrast effect, which occurs when X-rays pass the surfaces of objects. CONCLUSION: This technique may be suitable for clinical use and may contribute to improved image-quality in general radiography.

The first trial of phase contrast imaging for digital full-field mammography using a practical molybdenum x-ray tube.

RATIONALE AND OBJECTIVES: The image quality of a newly developed full-field digital phase contrast mammography (PCM) system and of a conventional screen-film (SF) mammography system were compared via images of a phantom and receiver operating characteristic (ROC) analysis of clinical images. METHODS: Magnified (1.75X) PCM images were scanned (sampling rate, 43.75 microm) and then reduced to original-sized, 25-micron pixel images printed on photothermographic film. Along with corresponding SF images, the phantom images were evaluated subjectively, and the clinical images of 38 patients were subjected to ROC analysis of mass and microcalcification. RESULTS: In the image quality of a phantom, the PCM exceeded the SF. In both mass and microcalcification, the ROC analysis Az values of the PCM clinical images surpassed those of the SF images. CONCLUSION: The PCM provides better images than the SF. Clinical trials suggest superior detection of both mass and microcalcification by full-field digital PCM over conventional SF mammography.