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In this work we present a novel 3D Monte Carlo photon transport program for simulation of multiple refractive scattering based on the refractive properties of X-rays in highly scattering media, like lung tissue. Multiple scattering reduces not only the quality of the image, but contains also information on the internal structure of the object. This information can be exploited utilizing image modalities such as Diffraction Enhanced Imaging (DEI). To study the effect of multiple scattering a Monte Carlo program was developed that simulates multiple refractive scattering of X-ray photons on monodisperse PMMA (poly-methyl-methacrylate) microspheres representing alveoli in lung tissue. Eventually, the results of the Monte Carlo program were compared to the measurements taken at the SYRMEP beamline at Elettra (Trieste, Italy) on special phantoms showing a good agreement between both data., 5 page, 7 figures

Diffraction Enhanced Imaging is a phase sensitive imaging modality, which recently has been demonstrated to be a powerful tool for improving the visibility of tiny low absorbing structures. Especially in medical imaging the capability to detect small details, not visible in a conventional radiograph is of relevant importance. An analyzer crystal is used as angular filter to select or reject X-rays that are deviated when traversing a sample if a gradient of the real part of the refractive index is encountered. At the medical imaging beamline of the synchrotron radiation facility Elettra (Trieste) experiments were carried out to assess the applicability of this technique to materials where a combined refraction from a large amount of small structures, not detectable separately, gives rise to an overall effect of multiple scattering. Tuning the analyzer crystal in different angular positions the variation of the contrast was studied. Strong contrast enhancement was measured in comparison to the conventional absorption image.