Münster 2017 – wissenschaftliches Programm
ST 4.5: Vortrag
Mittwoch, 29. März 2017, 17:45–18:00, JUR 1
X-Ray Grating Tomography without Phase-Retrieval — •Florian Schiffers1,2, Sebastian Käppler2, Shiyang Hu2, Jens Rieger1, Georg Pelzer1, Thilo Michel1, Christian Riess2, and Gisela Anton1 — 1Erlangen Centre for Astroparticle Physics, Friedrich-Alexander- Universität Erlangen-Nürnberg — 2Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg
Traditional Talbot-Lau X-ray Phase-Contrast tomography requires prior phase-retrieval based on - for instance stepping of the analyzer grating G2. Since several exposures per projection angle are required, high dose needs to be applied and simple integration into a continuously rotating gantry is cumbersome.
For the next step into clinical application it is desirable to have a tomographic reconstruction algorithm requiring only one phase-step per projection angle. Former work proposed a maximum-likelihood-based algorithm modeling the phase-contrast image formation process using the object's attenuation, refractive and small-angle scattering properties simultaneously, allowing tomographic reconstruction without the need of prior phase-retrieval by phase-stepping.
In this work we improve convergence using a smoothed initial reconstruction obtained by Filtered Backprojection of an interpolated estimation of the three sinograms: Absorption, differential phase-contrast and dark field. We demonstrate reconstruction of tomographic data acquired using a Talbot-Lau interferometer without phase-stepping with a polychromatic beam source.