A new DEI algorithm capable of investigating sub-pixel structures

Abstract

Diffraction enhanced imaging (DEI) is a phase-sensitive x-ray imaging technique based on the use of an analyser crystal placed between the sample and the detector. In the recent years, DEI has proven outstanding image quality both in material science and medical imaging, as well as the capability to provide quantitative information. However, in the case of objects featuring a fine refractive structure, which is not resolved by the spatial resolution of the detector, the fundamental requirements for the applicability of the DEI algorithm are not fulfilled. Herein a new algorithm is presented that takes into account this particular case. Formally similar to DEI, it allows obtaining quantitative information on the absorption and refraction properties of the object. Thus, structures in the sub-pixel length scale can be imaged and analysed quantitatively.

Absorption, refraction and scattering retrieval with an edge-illumination-based imaging setup

“…Applications of XPCI are extremely vast, ranging from biological and medical to security inspection and materials science. Several approaches exist for obtaining phase-contrast images in the X-ray regime, using large-scale synchrotron facilities and more compact X-ray-tube-based equipment [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The imaging methods, their developments and applications can also be found in recent reviews on the subject [18][19][20][21].…”

Phase Contrast Computed Tomography

“…Chapman et al (1997) demonstrated that it is possible to determine the phase quantitatively for pure phase objects. Later the same was shown in general (Pagot et al 2003, Wernick et al 2003, Rigon et al 2003. The method is difficult to extend to tomography as the crystals are normally aligned such that the derivative of the refractive index is measured in the direction parallel to the tomographic axis.…”

Potential for Imaging Engineered Tissues with X-Ray Phase Contrast

“…In scatter-based DEI, measurements are collected at the peak and toe (*15% of the max) of the rocking curve and this information is used to calculate X-ray absorption and USAXS images. 35 This method assumes that the probing X-ray wavefield experiences no net refraction due to large-scale variations in the refractive index distribution, which is typically not a valid assumption for medical imaging. 34 Extended DEI (eDEI) requires three data points taken at the peak and at the two maxima of the second derivative of the rocking curve.…”