Quantitative boundary reconstruction from truncated phase-contrast tomographic projections

Propagation-based phase-contrast tomography is a non-interferometric imaging technique that can reconstruct the complex refractive index distribution of an object. To accomplish such a reconstruction, however, the measured phase-contrast projections must be untruncated. We have demonstrated recently that the mathematical theory of local computed tomography (CT), which was originally developed for absorption CT, can be applied naturally for understanding the problem of reconstructing the location of image boundaries from truncated phase-contrast projections. In this work, we reveal that, for two-dimensional objects, the magnitude of refractive index discontinuities can be reconstructed from truncated phase-contrast projections acquired in the near-Fresnel zone. We show that these magnitudes can be reliably reconstructed using algorithms that were developed originally for local absorption CT.