Joint-reconstruction-enabled partial-dithering strategy for edge-illumination x-ray phase-contrast tomography

Edge illumination X-ray phase-contrast tomography (EIXPCT) is a emerging imaging technology in which partially opaque gratings are utilized with laboratory-based X-ray sources to estimate the distribution of the complex-valued refractive index. Spatial resolution in EIXPCT is mainly determined by the grating period of a sample mask, but can be significantly improved by a dithering technique in which multiple projection images are required per tomographic view angle as the object is moved over sub-pixel distances. Drawbacks of dithering include increased data acquisition times and radiation doses. Motivated by the flexibility in data acquisition designs enabled by a recently developed joint reconstruction (JR) method, a novel partial-dithering strategy for data acquisition is proposed. In this strategy, dithering is implemented at only a subset of the tomographic view angles. This results in spatial resolution that is comparable to that of the conventional full-dithering strategy where dithering is performed at every view angle, but the acquisition time is substantially decreased. The effect of dithering parameters on image resolution is explored.