Grid-based phase contrast and particularly the dark-field contrast contained within it offer the unique opportunity to map microscopic structure information (0.5 µm-50 µm) in large objects (up to 15 cm) two- and three-dimensionally. The main field of application is structural/damage analysis of fiber-reinforced plastic composites and testing micro-porous bio-implants.
Based on the X-ray Talbot interferometer, first presented in 2002, established micro-CT technology can be expanded for phase-contrast imaging. Here, microscopic incremental grids are used whose self-mapping is described by the Talbot effect and which are used in the interferometer for phase stepping. Instead of the usual X-ray weakening image three images form: 1. the absorption image, 2. the differential phase-contrast image, and 3. the dark-field image. In the last of these, the visibility loss caused by dissipation on microscopic limit surfaces and particles is coded. All three image contrasts can be used both for 2D component testing and for 3D micro-CT.