K-edge digital subtraction imaging based on a dichromatic and compact x-ray source

Abstract

This work proposes a compact dichromatic imaging system for the application of the K-edge digital subtraction technique based on a conventional x-ray tube and a monochromator system. A quasi-monochromatic x-ray beam at the energy of iodine K-edge is produced by Bragg diffraction on a mosaic crystal. Two thin adjacent beams with energies that bracket the K-edge discontinuity are obtained from the diffracted beam by means of a proper collimation system. They are then detected using an array of Si detectors. A home-made phantom is used to study the image quality as a function of iodine concentration. Signal and signal-to-noise ratio analysis has also been performed. The results are compared with theoretical expectations.

Effect of x‐ray energy dispersion in digital subtraction imaging at the iodine ‐edge—A Monte Carlo study

“…The obtained results demonstrated an interesting image quality also for iodine concentrations reduced with respect to normal clinical practice. 9,10 In the case of coronary angiography application, the aim is to acquire good quality images with the typical iodine concentrations that are obtained with intra-venous injection of the contrast medium, so as to avoid patient catheterization.…”

“…basis materials X and W. In our case, X is the contrast medium which should be isolated from the "fictitious" element W which comprises all the other ͑back-ground͒ materials. In order to have H = t X ͑i.e., to preserve in the log-subtracted image the quantitative information about the distribution of the contrast agent mass density͒ the weighting coefficients A and B must be set to9…”

A novel approach to background subtraction in contrast‐enhanced dual‐energy digital mammography with commercially available mammography devices: Polychromaticity correction

“…Lemacks et al 11 derived a general theoretical framework to perform the subtraction procedure in DM. Over the following years, a large number of optimization analyses, [12][13][14][15][16] detail detectability studies on dedicated phantoms, [17][18][19] and clinical validations 3,[20][21][22][23][24] have been carried out by several research teams worldwide. The focus of the present analysis will be set on the issues related to the mathematical aspects of CEDM that, quite broadly speaking, can be divided into two main branches that will be indicated here as monochromatic approximation and noise minimization.…”

Ratio-contrast imaging of dual-energy absorption for element mapping with a scanning transmission X-ray microscope

“…Because the change in photon energies is only a few percent or less, the absorption of X-rays by all the other elements in the specimen is negligible, and consequently any observed difference in the transmitted X-ray flux between the two images obtained at the two energies can be attributed to the presence of the element being studied (Rarback et al, 1987). With this method the measurement of elemental spatial distributions has been achieved using various light sources (Houk et al, 1979;Sarnelli et al, 2004Sarnelli et al, , 2006Umetani et al, 1996) and has been widely applied to many science fields, especially in the medical area (Lewis, 1997;Krug et al, 2006;Bewer et al, 2008;Takeda et al, 1998). Among these light sources, synchrotron radiation offers several advantages for absorption-contrast imaging, such as high intensity, high brilliance, natural collimation of the radiation, and energy consecutive tunability of the emitted X-rays, which makes it possible to select a narrow wavelength band with a monochromator (Suortti & Thomlinson, 2003).…”