Photo: Conventional X-ray and dark field
Chicken wings - Traditional absorption
image (left), Dark-field image
(right); © Franz Pfeiffer, EPFL/PSI

Up until this point, dark-field x-ray imaging required sophisticated optics and could only be produced at facilities like the PSI‘s synchrotron. With the new nanostructured gratings described in this research dark-field images could maybe soon be produced using ordinary x-ray equipment already in place in hospitals and airports.

Unlike traditional x-ray images, which show a simple absorption contrast, dark-field images capture the scattering of the radiation within the material itself, exposing subtle inner changes in bone, soft tissue, or alloys. The overall clarity of the images is striking. The improved sensitivity in measuring bone density and hairline fractures could help diagnose the onset of osteoporosis. Because cancer or plaque cells scatter radiation slightly differently than normal cells, dark-field x-ray images can also be used to explore soft tissue, providing safer early diagnosis of breast cancer or the plaques associated with Alzheimer‘s disease.

„Researchers have been working on dark-field x-ray images for many years,“ explains Franz Pfeiffer, a professor at EPFL and researcher at the PSI. „Up until now these images have only been possible using sophisticated crystal optical elements.“ Crystal optics, however, only work for a single x-ray wavelength and thus are highly inefficient. „Our new technique uses novel x-ray optical components, in the form of nanostructured gratings, that permit the use of a broad energy spectrum, including the standard range of energies in traditional x-ray equipment used in hospitals or airports,“ adds Christian David from PSI. „This opens up the possibility for adapting current imaging equipment to include dark-field imaging.“

Pfeiffer plans to develop an adaptation for existing medical equipment. „When combined with the phase contrast imaging technique that we developed in 2006, we now have the possibility of providing the same range of imaging techniques in broad-spectrum x-ray imaging that we do with visible light.“

MEDICA.de; Source: Ecole Polytechnique Fédérale de Lausanne