Multimodal Phase-Based X-Ray Microtomography with Nonmicrofocal Laboratory Sources

We present an alternative laboratory implementation of x-ray phase-contrast tomography through a beam-tracking approach. A nonmicrofocal rotating anode source is combined with a high-resolution detector and an absorbing mask to obtain attenuation, phase, and ultra-small-angle scattering tomograms of different specimens. A theoretical model is also presented which justifies the implementation of beam tracking with polychromatic sources and provides quantitative values of attenuation and phase, under the assumption of low sample attenuation. The method is tested on a variety of samples featuring both large and small x-ray attenuation, phase, and scattering signals. The complementarity of the contrast channels can enable subtle distinctions between materials and tissue types, which appear indistinguishable to conventional tomography scanners.