Tomographic phase reconstruction using a tilted Laue analyser crystal. (2020)
Type of ContentElectronic Thesis or Dissertation
Thesis DisciplineMedical Physics
Degree NameMaster of Science
PublisherUniversity of Canterbury
AuthorsChalmers, Mitchellshow all
Analyser-Based Phase Contrast Imaging (ABPCI) is a promising phase contrast method due to its high image resolution of soft tissues and high signal to noise ratio with its biggest downside being the experimental setup complexity. One of the main drawbacks of ABPCI is that its two-dimensional (2-D) images only provide 1-D phase sensitivity . The aim of the work is to apply the methodology of inclined geometry proposed by Rutishauser et al  to ABPCI to significantly improve the image quality of the reconstructed ABPCI images for quantitative analysis.
We employed a Laue analyser crystal to perform analyser-based based phase contrast imaging and took tomographic datasets over 360◦ of rotation similar to  with the detector and sample tilted by 8◦ clockwise following the propagation direction of the x-ray wavefield. We measured the refractive coefficient δ to be approximately a factor of 2 off the reference values with the β values in agreement for media in the perspex phantom. This is probably due to underestimation of the phase gradients due to the application of the geometric optics approximation and misalignment of the transmitted and diffracted projections as well as the ∆θ and ∆θ180 maps. These errors are then integrated which amplifies the low frequency noise.