Modeling Vibrations of a Tiled Talbot-Lau Interferometer on a Clinical CT

X-ray computed tomography (CT) is an invaluable imaging technique for non-invasive medical diagnosis. However, for soft tissue in the human body the difference in attenuation is inherently small. Grating-based X-ray phase-contrast is a relatively novel imaging method which detects additional interaction mechanisms between photons and matter, namely refraction and small-angle scattering, to generate additional images with different contrast. The experimental setup involves a Talbot-Lau interferometer whose susceptibility to mechanical vibrations hindered acquisition schemes suitable for clinical routine in the past. We present a processing pipeline to identify spatially and temporally variable fluctuations occurring in an interferometer installed on a continuously rotating clinical CT gantry. The correlations of the vibrations in the modular grating setup are exploited to identify a small number of relevant fluctuation modes, allowing for a sample reconstruction free of vibration artifacts.

Automated summary

X-ray computed tomography (CT) is a valuable imaging technique for non-invasive medical diagnosis. However, it has limitations in imaging soft tissue due to small differences in attenuation. Grating-based X-ray phase-contrast imaging detects additional interaction mechanisms between photons and matter to generate images with different contrast. A processing pipeline is presented to identify and correct fluctuations caused by mechanical vibrations in an interferometer installed on a rotating clinical CT gantry, allowing for vibration-free sample reconstruction.