High-resolution quantitative phase-contrast X-ray imaging for biomedical samples at PETRA III

Phase-contrast computed tomography enables visualizing soft tissue samples with high contrast. At the same time, typically used phase-retrieval techniques often compromise spatial resolution or phase sensitivity. In order to increase the spatial resolution for quantitative phase-contrast measurements, we built a new speckle-based imaging setup at the beamline P05 and P07 operated bz Hereon at Petra III / DESY. By exchanging the wavefront marker with a 2D phase grating as wavefront marker, we improved the visibility allowing for faster scan acquisition. We developed a post processing chain which is able to compensate wavefront marker vibrations and tested the setup capabilities and resolution at different phase-retrieval settings. The setup was able to successfully image biomedical samples at a spatial resolution down to 2.1 μm. By doing so, a resolution level close to the system resolution and comparable to propagation based imaging is reached, while at the same time no assumptions about the sample are made and quantitative electron density information can be accessed.