The Talbot-Lau grating interferometer enables refraction based imaging with conventional X-ray tubes, offering the
promise of a new medical imaging modality. The fringe contrast of the normal incidence interferometer is however
insufficient at the >40 keV photon energies needed to penetrate thick body parts, because the thin absorption gratings used in the interferometer become transparent. To solve this problem we developed a new interferometer design using gratings at glancing incidence. For instance, using 120 μm thick Au gratings at 10° incidence we increased several fold the interferometer contrast for a spectrum with ~58 keV mean energy. Tests of DPC-CT at 60-80kVp using glancing angle interferometers and medically relevant samples indicate high potential for clinical applications. A practical design for a slot-scan DPC-CT system for the knee is proposed, using glancing angle gratings tiled on a single substrate.
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D. Stutman ; J. W. Stayman ; M. Finkenthal and J. H. Siewerdsen
High energy x-ray phase-contrast imaging using glancing angle grating interferometers
", Proc. SPIE 8668, Medical Imaging 2013: Physics of Medical Imaging, 866814 (March 19, 2013); doi:10.1117/12.2007930; http://dx.doi.org/10.1117/12.2007930