February 5, 2008 A breakthrough by European researchers has the potential to expand the application of powerful "dark-field" x-ray imaging using standard medical and industrial imaging equipment. Normally only possible via prohibitively expensive and sophisticated crystal optics, the detailed images produced by "dark-field" x-rays could be applied to diagnose breast cancer or Alzheimer’s disease, identify explosives in hand luggage, or pinpoint hairline cracks in airplane wings.
While traditional x-rays produce a simple absorption contrast image the dark-field x-ray image technology captures the scattering of the radiation within the material itself. This gives the operator a clear, defined image and can show subtle inner changes in bone, soft tissue, or alloys.
The technique developed by researchers at the Paul Scherrer Institute (PSI) in conjunction with the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland, delivers improved sensitivity that will allow medical practitioners to measure bone density and hairline fractures which could help diagnose osteoporosis. As dark-field x-ray images can also be used to explore soft tissue and as cancer or plaque cells scatter radiation slightly differently than normal cells, practitioners could use it to diagnose illnesses such as breast cancer or Alzheimer’s disease.
There are also possible uses in the airline and travel industries, explosives in luggage could be more easily identified using security screening equipment and dark-field images could help reveal scattering-producing micro-cracks and corrosion in airplane wings.
“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,” said Pfeiffer’s colleague, Christian David, “This opens up the possibility for adapting current imaging equipment to include dark-field imaging.”
Pfeiffer plans to collaborate with the Center for Biomedical Imaging (CIBM), a joint center with the Universities of Lausanne and Geneva and their associated hospitals, to develop an adaptation for existing medical equipment.