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Beam hardening effects in grating‐based x‐ray phase‐contrast imaging
Author(s) -
Chabior Michael,
Donath Tilman,
David Christian,
Bunk Oliver,
Schuster Manfred,
Schroer Christian,
Pfeiffer Franz
Publication year - 2011
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3553408
Subject(s) - phase contrast imaging , optics , materials science , medical imaging , x ray phase contrast imaging , phase contrast microscopy , phase imaging , contrast (vision) , phase (matter) , grating , medical physics , physics , radiology , medicine , microscopy , quantum mechanics
Purpose: In this work, the authors investigate how beam hardening affects the image formation in x‐ray phase‐contrast imaging and consecutively develop a correction algorithm based on the results of the analysis. Methods: The authors' approach utilizes a recently developed x‐ray imaging technique using a grating interferometer capable of visualizing the differential phase shift of a wave front traversing an object. An analytical description of beam hardening is given, highlighting differences between attenuation and phase‐contrast imaging. The authors present exemplary beam hardening artifacts for a number of well‐defined samples in measurements at a compact laboratory setup using a polychromatic source. Results: Despite the differences in image formation, the authors show that beam hardening leads to a similar reduction of image quality in phase‐contrast imaging as in conventional attenuation‐contrast imaging. Additionally, the authors demonstrate that for homogeneous objects, beam hardening artifacts can be corrected by a linearization technique, applicable to all kinds of phase‐contrast methods using polychromatic sources. Conclusions: The evaluated correction algorithm is shown to yield good results for a number of simple test objects and can thus be advocated in medical imaging and nondestructive testing.