Asymmetric Illumination X-ray Differential Phase Contrast Imaging

Abstract

In this dissertation, we present a novel, low-cost approach to x-ray phase contrast imaging (XPCI). This method, which we term asymmetric illumination x-ray phase contrast imaging (AIXPCI), is compatible with a broadband tabletop x-ray source in a conventional laboratory setting and utilizes an angular filtration grid within the system to obtain phase gradient sensitivity. This grid is customizable and can be created with an inexpensive commercial 3D printer in under 2 hours with printing costs under $15. We began experimental validation of the AIXPCI approach, first with a single pixel experiment, in which we observed the expected intensity variations between two measurements obtained with different rotations of the angular filter, and then with a full detector implementation with our fabricated grid. We found the recovered phase gradient behaved qualitatively as expected according to theory and we obtained experimental results within a factor of 2.05 of simulated results confirming potential of this technique as a quantitative XPCI method. Since the method only requires the addition of a singular angular filter, there are reduced alignment requirements compared to similar XPCI methods that require multiple apertures or grids. The minimal equipment and alignment constraints should enable implementation of the method within existing x-ray imaging systems. These benefits would allow the use of XPCI to extend to a wider variety of applications.