Low dose X-ray phase contrast imaging sensitive to phase effects in 2-D

Abstract

X-ray absorption imaging is a widespread imaging technique in biology and industry as well as diagnostic imaging of the human body in medicine. However, in many situations, there is the need to distinguish between low absorption and even low contrast features such as cancerous and normal tissue in mammography. In this case, the applicability of conventional absorption imaging is limited. X-ray phase contrast imaging (XPCI) is a powerful imaging technique providing enhanced contrast since the real (phase) part δ of the refractive index (1-δ-iβ) is several orders of magnitude larger than the imaginary (absorption) part β. In our previous work, we introduced a new XPCI method based on precise sub-pixel position determination of the X-ray pattern projected by the grating directly from the pattern image enabling to achieve high-quality 1-D phase and absorption images simultaneously in a single exposition. In this contribution, we present the extension of our 1-D single grating method to 2-D. Even though the advantages of two-directional sensitivity have been discussed since the XPCI technique was pioneered, the existing grating methods enable to measure the 2-D information usually only by a two-fold usage of the 1-D approach with all its drawbacks (multiple exposures during phase-stepping). Using the suggested method, in a single exposure, phase gradient images in two perpendicular directions together with the conventional attenuation image are produced. In this contribution, we present the first results with our 2-D sensitive approach.