Phase contrast imaging

Abstract

X-ray devices for Phase Contrast Imaging (PCI) are often built up with the help of gratings. For large field-of-views (FOV), production cost and complexity of these gratings could increase significantly as they need to have a focused geometry. Instead of a pure PCI with a large FOV, this invention suggests to combine a traditional absorption X-ray imaging system with large-FOV with an insertable low-cost PCI system with small-FOV, The invention supports the user to direct the PCI system with reduced FOV to a region that he regards as most interesting for performing a PCI scan thus eliminating X-ray dose exposure for scanning regions not interesting for a radiologist. The PCI scan may be generated on the basis of local tomography.

Description

technical field [0001] The present invention relates to differential phase contrast imaging (PCI), and in particular, the present invention relates to apparatus and methods for differential phase contrast imaging. Background technique [0002] Conventional X-ray systems for medical applications are mainly based on the difference in absorption of X-rays in matter, resulting in projection images formed by the cumulative absorption of X-rays along a line. However, matter affects not only the absorption of X-rays but also the refraction of X-rays. This property portends higher X-ray contrast between human tissue types than conventional absorption-based imaging, and thus could represent a future improvement. One possible setup to facilitate PCI is raster based. [0003] The problem facing the use of gratings in the transmitted X-ray beam is that unfocused gratings produce less absorption modulated by the grating itself, especially outside the central region of the field of view...

AI Technical Summary

Problems solved by technology

Another disadvantage of differential phase contrast CT is that the noise power spectrum of the image has a peak in the low frequency region

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