Deconvolution by finite-size-source effects of x-ray phase-contrast images

Methods: To enhance the quality of phase-contrast images without increasing the dose, a possible approach could be the partial deconvolution of the finite source size effects by experimental phase-contrast images. The deconvolution procedure, the authors propose, employs the acquisition of two images on a suitable well-known test sample, one in contact and the other in phase-contrast conditions. Both acquired images are used along with a simulated phase-contrast image (obtained from the test sample in ideal conditions of pointlike source illumination) to correctly retrieve the experimental source distribution function. This information allows a generic experimental phase-contrast image, acquired in the same conditions, to be partially deconvolved by finite source size effects.

Purpose: In the hard x-ray region, the cross sections for the phase shift of low-Z elements are about 1000 times larger than the absorption ones. As a consequence, phase contrast is detectable even when absorption contrast is minimal or absent. Therefore, phase-contrast imaging could become a valid alternative to absorption contrast without delivering high dose to tissue/human body parts.