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

摘要

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.