by John R. Fischer
, Senior Reporter | February 14, 2022
Researchers at the Technical University of Munich have been able to derive more insights about human tissue for diagnosis through a combination of CT scanning and dark-field X-ray imaging.
Dark-field imaging provides information that conventional X-rays cannot on fine tissue structures, especially the lung. In conventional X-ray imaging, X-rays are attenuated by intervening tissue as they travel to the source of the detector. This creates images with varying degrees of attenuation that are based on tissue type and structures. When the X-rays interact with materials of different densities, such as an interface, they scatter. Dark-field imaging assesses this scattering effect to obtain more information on very fine tissue structures.
Technical challenges have made it hard to develop a dark-field CT device to the scale needed to assess human beings. But through their work, TUM researchers have developed a prototype that combines both technologies to produce 3D dark-field X-ray images. And it has already been used with a thorax phantom that depicts the upper human body and is large enough to repeat intended applications on real patients.
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Dark-field X-ray imaging can provide more information about fine tissue structures, especially the lung
With the technique, providers can capture both conventional and dark-field X-ray images in a single scan and diagnose not just lung diseases but distinguish between various types of kidney stones and tissue deposits, authors Nikolai Gustschin and Manuel Viermetz told HCB News. "A sensitive assessment of microstructural, pathophysiological changes in tissue and their anatomical distribution provides complementary diagnostic information, which is not accessible with attenuation imaging only. It could hence facilitate a more accurate, quantitative detection and effective treatment of diseases in their early stages."
The technique relies on three optical gratings placed between the X-ray source and detector. When X-rays pass through the gratings, a characteristic pattern is produced at the detector and then changes when a person is positioned in the path of the beam. It is from these deviations that dark-field imaging is able to assess the structure of the person’s tissue. It also requires only 1/50th of the radiation dose typically used in CT scanning.