Elodie Pagot | PubMed Health

PubMed2005

Phase-contrast X-ray imaging combining free space propagation and Bragg diffraction.

The combination of X-ray 'propagation-based' and 'analyzer-based' phase-contrast imaging with a perfect crystal-analyzer is investigated. The image pattern produced using this 'hybrid' imaging technique presents peculiar features that can be interpreted as a mixture of the two independent phase-contrast signals. A quantitative analysis has been performed in terms of signal-to-noise ratio for the three techniques considered in this paper. Results show that in the 'hybrid imaging' technique this parameter has a weaker dependence on the angular alignment of the crystal analyser with respect to the 'analyser-based' imaging. This pioneering experiment indicates that this hybrid imaging technique might permit simultaneous advantage of the specific features of the two imaging methods to be taken.

Absorption↗

PubMed2005

Quantitative comparison between two phase contrast techniques: diffraction enhanced imaging and phase propagation imaging.

Two x-ray phase contrast imaging techniques are compared in a quantitative way for future mammographic applications: diffraction enhanced imaging (DEI) and phase propagation imaging (PPI). DEI involves, downstream of the sample, an analyser crystal acting as an angular filter for x-rays refracted by the sample. PPI simply uses the propagation (Fresnel diffraction) of the monochromatic and partially coherent x-ray beam over large distances. The information given by the two techniques is assessed by theoretical simulations and compared at the level of the experimental results for different kinds of samples (phantoms and real tissues). The imaging parameters such as the energy, the angular position of the analyser crystal in the DEI case or the sample to detector distance in the PPI case were varied in order to optimize the image quality in terms of contrast, visibility and figure of merit.

Breast Neoplasms↗