A method to extract quantitative information in analyzer-based x-ray phase contrast imaging

Analyzer-based imaging is a powerful phase-sensitive technique that generates improved contrast compared to standard absorption radiography. Combining numerically two images taken on either side at +/-1/2 of the full width at half-maximum (FWHM) of the rocking curve provides images of pure refraction and of apparent absorption. In this study, a similar approach is made by combining symmetrical images with respect to the peak of the analyzer rocking curve but at general positions, +/-alpha.FWHM. These two approaches do not consider the ultrasmall angle scattering produced by the object independently, which can lead to inconsistent results. An accurate way to separately retrieve the quantitative information intrinsic to the object is proposed. It is based on a statistical analysis of the local rocking curve, and allows one to overcome the problems encountered using the previous approaches. (C) 2003 American Institute of Physics.