Contrast improvement with Diffraction Enhanced Imaging for scattering materials

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.