X-ray phase-contrast imaging: From synchrotrons to compact systems.

Compared to conventional attenuation-based radiography, X-ray phase-contrast imaging (XPCI) enhances the visibility of low-$Z$ or microgranular structures within the sample, being appealing for applications on soft and/or microstructured tissues/materials. XPCI comes in a variety of techniques, most of them pioneered in synchrotrons due to the ideal imaging conditions, $i.e.$, high coherence and flux, offered by synchrotron radiation. Nowadays, while being $de facto$ a standard at synchrotrons, great efforts are being devoted to the translation of XPCI to compact systems that can be fitted in a laboratory or in a hospital. This involves technological developments either towards high brilliance X-ray sources ($e.g.$, liquid anode, inverse-Compton), or towards relaxed coherence requirements obtained through structured absorbing optical elements (as in, $e.g.$, edge illumination, grating interferometry). In this contribution, the working principles of some widely used XPCI techniques and successful examples of translation to laboratory systems will be presented.