Mammography imaging studies using a Laue crystal analyzer

Abstract

Synchrotron based mammography imaging experiments have been performed with monochromatic x-rays in which a laue crystal placed after the object being imaged has been used to split the beam transmitted through the object. The X27C R&D beamline at the National Synchrotron Light Source was used with the white beam monochromatized by a double crystal Si(1 11) monochromator tuned to 18keV. The imaging beam was a thin horizontal line approximately 0.5mm high by 100-wide. Images were acquired in line scan mode with the phantom and detector both scanned together. The detector for these experiments was an image plate. A thin Si(1 1 1) laue analyzer was used to diffi.act a portion of the beam transmitted through the phantom before the image plate detector. This "scatter fiee" diffracted beam was then recorded on the image plate during the phantom scan. Since the thin laue crystal also transmitted a hction of the incident beam, this beam was also simultaneously recorded on the image plate. The imaging results are interpreted in terms of an x-ray schliere or rehctive index inhomogeneities. The analyzer images taken at various points in the rocking curve will be presented.

A quantitative, non-interferometric X-ray phase contrast imaging technique

“…(3) means that we assume that the sample has constant phase and absorption gradients within the transmitting region of the presample aperture. Then, by applying the paraxial approximation to the Fresnel-Kirchhoff diffraction integral the complex amplitude incident upon A 2 may be found according to [38]: (4) where, since we are ultimately interested in |U(x)|, complex phase terms dependent upon y have been omitted and (5) Where U 0 represents the amplitude of the incident wave emitted by the source. As in Ref.…”

“…Image contrast thus arises due to spatial variation of an object's thickness and constituent material absorption coefficients. Since the pioneering work of Bonse and Hart [1], a variety of techniques have been developed to acquire X-ray images possessing contrast due to sample induced phase shifts [2][3][4][5][6][7]. Such images are referred to as phase contrast images.…”

A simplified approach to quantitative coded aperture X-ray phase imaging

“…All other system parameters are as described in Sec. (3). We considered a polyetheretherketone (PEEK) fiber of radius 100μm, assumed to have chemical composition C 19 O 3 H 18 and density 1.3 gm/cm 3 .…”

“…ABI develops contrast using the rocking curve of an analyser crystal [2]. Algorithms were developed to extract sample phase and absorption from images taken on two opposing sides of the analyser crystal rocking curve [3,4]. Algorithms employing a variety of assumptions about the sample and imaging system, and later, for more general systems were subsequently developed [5][6][7][8].…”

Application of Diffraction Enhanced Imaging to Medical Imaging

“…Chapman has been involved for the last several years with medical imaging projects associated with synchrotron radiation [1][2][3][4][5][6][7][8][9]. More recently, he was a codeveloper of the Diffraction Enhanced Imaging (DEI) technique [1][2][3][4]9].…”