A 3-D Projection Model for X-ray Dark-field Imaging

Language
en
Document Type
Article
Issue Date
2020-03-26
Issue Year
2019
Authors
Felsner, Lina
Hu, Shiyang
Maier, Andreas
Bopp, Johannes
Ludwig, Veronika
Anton, Gisela
Riess, Christian
Editor
Publisher
Springer Nature
Abstract

The X-ray dark-field signal can be measured with a grating-based Talbot-Lau interferometer. It measures small angle scattering of micrometer-sized oriented structures. Interestingly, the signal is a function not only of the material, but also of the relative orientation of the sample, the X-ray beam direction, and the direction of the interferometer sensitivity. This property is very interesting for potential tomographically reconstructing structures below the imaging resolution. However, tomographic reconstruction itself is a substantial challenge. A key step of the reconstruction algorithm is the inversion of a forward projection model. In this work, we propose a very general 3-D projection model. We derive the projection model under the assumption that the observed scatter distribution has a Gaussian shape. We theoretically show the consistency of our model with existing, more constrained 2-D models. Furthermore, we experimentally show the compatibility of our model with simulations and real dark-field measurements. We believe that this 3-D projection model is an important step towards more flexible trajectories and, by extension, dark-field imaging protocols that are much better applicable in practice.

Journal Title
Scientific Reports
Volume
9
Citation
Scientific Reports 9 (2019). <https://www.nature.com/articles/s41598-019-45708-9>
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