Low-dose, simple, and fast grating-based X-ray phase-contrast imaging

TLDR

Phase‑sensitive X‑ray imaging with gratings offers substantially higher contrast than conventional absorption imaging, yet conventional phase‑stepping methods require multiple projections, limiting broader adoption. The authors aim to develop a grating‑interferometry based tomographic phase‑contrast imaging method that eliminates the need for phase stepping. They use a grating‑interferometry technique that extracts phase‑contrast signals directly, avoiding phase‑stepping. The reverse‑projection method achieves lower dose and higher efficiency than phase‑stepping while preserving image quality, paving the way for fast, low‑dose phase‑contrast imaging of biological specimens and in vivo studies.

Abstract

Phase sensitive X-ray imaging methods can provide substantially increased contrast over conventional absorption-based imaging and therefore new and otherwise inaccessible information. The use of gratings as optical elements in hard X-ray phase imaging overcomes some of the problems that have impaired the wider use of phase contrast in X-ray radiography and tomography. So far, to separate the phase information from other contributions detected with a grating interferometer, a phase-stepping approach has been considered, which implies the acquisition of multiple radiographic projections. Here we present an innovative, highly sensitive X-ray tomographic phase-contrast imaging approach based on grating interferometry, which extracts the phase-contrast signal without the need of phase stepping. Compared to the existing phase-stepping approach, the main advantages of this new method dubbed “reverse projection” are not only the significantly reduced delivered dose, without the degradation of the image quality, but also the much higher efficiency. The new technique sets the prerequisites for future fast and low-dose phase-contrast imaging methods, fundamental for imaging biological specimens and in vivo studies.