Quantitative x-ray dark-field computed tomography

• Published in: Physics in medicine & biology 2010-09, Vol.55 (18), p.5529-5539
• Main Authors: Bech, M, Bunk, O, Donath, T, Feidenhans'l, R, David, C, Pfeiffer, F
• Format: Article
• Language: English
• Subjects: Darkness; Diffusion; Image Processing, Computer-Assisted; Linear Models; Phantoms, Imaging; Tomography, X-Ray Computed - methods
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/0031-9155/55/18/017

The basic principles of x-ray image formation in radiology have remained essentially unchanged since Röntgen first discovered x-rays over a hundred years ago. The conventional approach relies on x-ray attenuation as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpret image formation. Phase-contrast or coherent scatter imaging techniques, which can be understood using wave optics rather than ray optics, offer ways to augment or complement the conventional approach by incorporating the wave-optical interaction of x-rays with the specimen. With a recently developed approach based on x-ray optical gratings, advanced phase-contrast and dark-field scatter imaging modalities are now in reach for routine medical imaging and non-destructive testing applications. To quantitatively assess the new potential of particularly the grating-based dark-field imaging modality, we here introduce a mathematical formalism together with a material-dependent parameter, the so-called linear diffusion coefficient and show that this description can yield quantitative dark-field computed tomography (QDFCT) images of experimental test phantoms.