Cone-beam x-ray phase-contrast tomography for the observation of single cells in whole organs

Multiscale X-Ray Analysis of Biological Cells and Tissues by Scanning Diffraction and Coherent Imaging

“…The holographic projections are inverted by phase retrieval algorithms. In the most simple case, the phase shift of the object, that also encodes the electron density, can be retrieved in a single inversion step using for example the contrast transfer function [65] or transport of intensity equation [66,67]. In many cases, due to rather stringent assumptions about the sample and the probing beam, this procedure can introduce artifacts that can be circumvented by iterative algorithms.…”

“…scanning SAXS recordings, can be advantageously combined with lensless coherent imaging of the cell's (projected) electron density. In this respect, a fullfield low-dose holographic image is recorded by moving the sample downstream from the focal plane, as sketched in gorithm, here based on the modified iterative hybrid-input-output algorithm [80] and for the first time extended to multiple defocus distances [65].…”

“…While the mHIO algorithm was originally designed for single-distance phase retrieval of pure phase objects [80], the multi-distance extension can phase also mixed objects by employing longitudinal diversity. In addition, the signal-to-noise ratio and convergence speed increases, and residual low-frequency components after background subtraction are less detrimental for image quality [65]. The extension to multiple distances is implemented such that the iteration result from one distance is used to initialize the next iteration for the consecutive distance, looping sequentially over all distances.…”

3d virtual histology of neuronal tissue by propagation-based x-ray phase-contrast tomography

“…However, imperfections in the recording process or data analysis can yield strong artifacts in the reconstruction, of which the most common are described in the following analogously to [88].…”

Nanoscale holographic tomography of heart tissue with x-ray waveguide optics

“…The pitch angle α = arctan ∆z ∆x is then corrected by a tilt stage below the rotation stage. 8 (b) Eventual misalignment of the roll angle β is accounted for by image rotation after data acquisition. To this end, two slices are reconstructed and the position of the tomographic axis is refined.…”