Very low dose mammography: new perspectives in Diffraction Enhanced Imaging (DEI) mammography

Diffraction Enhanced Imaging (DEI) can significantly improve the expressiveness of mammography radiographs. Whereas the contrast in conventional radiographs is based on small X-ray absorption differences of tissues, the contrast mechanism of DEI is, in addition, partially related to the differences in X-ray refraction properties. DEI has been successfully applied to in-vitro mammography studies where little absorption tissue differentiation is present. In this paper we will present work on high-energy DEI mammography, which has been carried out by utilizing a tunable monochromatic X-ray beam. Since the refraction characteristics of soft tissues are much less energy dependent than absorption, the use of high energy X-rays is favoured. They can be employed in mammographic imaging without reducing the image contrast, while getting the benefit of reduced dose since the X-ray absorption falls off considerably. In-vitro images of an American College of Radiology (ACR) mammographic phantom using monochromatic X-rays through 50 keV have been obtained with a digital detector. High-energy mammography has been successfully performed at a significantly lower dose than that usually applied in clinical mammography without important contrast loss.