A New Vision for X-ray Soft Tissue Imaging

The small difference in the compositions between types of soft tissues, tend to limit the amount of absorption contrast. Conventional radiography derives contrast from an object's X-ray absorption. In general, the best absorption contrast is obtained at X-ray energies where the absorption is high meaning high absorbed dose. Diffraction Enhanced Imaging (DEI) and its extension, Multiple Image Radiography (MIR) are radiographic techniques that derive contrast from an object's X-ray absorption, refraction gradient and ultra small angle scatter-rejection (extinction) properties. The refraction angle image of DEI/MIR visualizes the spatial gradient of the projected electron density of the object, which often correlates well with the projected physical density and projected absorption in soft tissue imaging. The projected electron density (or the mass density, a related quantity) is not an "energy" dependent property of the object as is the case of absorption. This simple difference can lead to soft tissue imaging with less X-ray exposure. In this paper, we present the method of obtaining an equivalent image to the radiograph "DEI/MIR integral image" and applications to soft tissue imaging problems including breast cancer imaging.