Simultaneous Wavefront and 3D Tomographic Reconstructions for Phase Imaging Using Hartmann Sensor

X-ray absorption imaging is used in the medical field since a long time, but recent advance in phase-contrast imaging made it feasible in a clinical setup. X-ray Phase-contrast imaging technique using a Hartmann sensor allows extracting the absorption and phase information in a single acquisition, allowing to extract a phase-shift information with a minimal exposition and deposited dose. This is at the cost of resolution, since each spot from the grid becomes a single value on the image. Despite higher resolutions with smaller spots are more sensitive to noise, we implement this technique in a tomographic setup to obtain precise phase-related 3D information on the sample. An iterative wavefront reconstruction (IR-WF) algorithm is necessary to extract the phase and absorption values from an acquired image. Existing methods compute projections separately, so the consistency between the overall projections is not assumed. Our method consists in merging the wavefront reconstruction with a computed tomographic iterative reconstruction (IR-CT) to ensure that all images converge to the same result.