Phase contrast imaging with polycapillary optics

Abstract

Conventional diagnostic radiography is limited by the similarity between x-ray absorption coefficients of normal tissue and carcinoma, which results in poor inherent subject contrast. Differences in x-ray refractive indices are much larger, so phase imaging has the potential for higher contrast. Unfortunately, the spatial coherence necessary for simple in-line phase contrast requires small sources at large distances, and hence excessive exposure times. Other schemes such as grating techniques require multiple images and complex alignment. In this work, polycapillary optics were employed to increase the intensity of the x-ray beam for simple propagation in-line imaging. Focusing through pinhole apertures created a small virtual source of high intensity from which phase contrast edge effects were observed with tissueequivalent phantoms.