3. Phase contrast and dark field

We conclude this article with a look at new X-ray imaging techniques, known as "phase contrast" and "dark field", which are being worked on in a number of laboratories, but for which it is still so controversial that it is difficult to predict whether they will bring concrete advances in medical imaging. In 2015, these techniques are still in the making, and will require major breakthroughs if they are to become widespread: first and foremost, powerful point sources, and to a lesser extent, high-performance technologies for the manufacture of interferometric devices. As things stand, they offer a number of advantages, particularly in dark field mode (visibility of structures far below detector resolution). For the detection of calcifications, this technique offers a gain in contrast of between 3 and 8 dB: mammography could be the first application, if this technique lives up to its promise....