Diffraction enhanced imaging and x‐ray fluorescence microtomography for analyzing biological samples

Abstract

In this work, breast tissue samples were investigated in order to verify the distribution of certain elements by x‐ray fluorescence computed tomography (XRFCT) correlated with the characteristics and pathology of each tissue observed by diffraction enhanced imaging (DEI). The DEI system can show details in low attenuation tissues. It is based on the contrast imaging obtained by extinction, diffraction and refraction characteristics and can improve reduction in false positive and false negative diagnoses. XRFCT allows mapping of all elements within the sample, since even a minute fluorescence signal can be detected. DEI imaging techniques revealed the complex structure of the disease, confirmed by the histological section, and showed microstructures in all planes of the sample. The XRFCT showed the distribution of Zn, Cu and Fe at higher concentration. Copyright © 2007 John Wiley & Sons, Ltd.

Molecular phylogenetic relationships and phenotypic diversity in miniaturized toadlets, genus Brachycephalus (Amphibia: Anura: Brachycephalidae)

“…3): (1) anterior end of suture between premaxillae; (2) tip of the palatine process on the premaxilla; (3) anteriormost corner of the frontoparietal; (4) anterior end of suture between frontoparietals; (5) anterolateral corner of the frontoparietal; (6) anterior end of the projection of the pars facialis; (7) maximum anterior curvature of the otic capsule; (8) anterior end of the projection of the parotic plate overlying the prootic; (9) tip of the zygomatic ramus on the squamosal; (10) latero-posterior end of the prootic; (11) medial-posterior end of the prootic; (12) posterior curvature of the prootic; (13) anterolateral curvature of prootic; (14) anterior tip of the occipital condyle; and (15) center of the foramen magnum. The x-and y-coordinates of each landmark were obtained using tpsDig software (Rohlf, 2006) on microradiographs taken with an X-ray microfocus tube and an image plate detector (Rocha et al, 2007). Because of symmetry, landmarks were defined from only one side of the skull.…”

X-Ray Fluorescence Microtomography in Biological Applications

“…The main advantage of X-ray Fluorescence Microtomography (XRF CT) resides in being a non-destructive technique, allowing the use of the same sample for further characterization with other kind of techniques like X-ray diffraction (Rocha et al, 2007). In comparison with conventional micro X-ray fluorescence analysis, the XRF CT does not require any sample preparation such as embedding or fixing the samples in paraffin to get an ultrafine and accurate slices (approximately 15 microns).…”

“…Both excess and deficiency of trace elements have been associated with many diseases including cancer. However, until now, the evidence linking iron, copper and zinc to cancer is far from being conclusive (Rocha et al, 2007) and further research is needed. Using XRFµCT the elemental map can be obtained.…”

“…Both excess and deficiency of trace elements have been associated with many diseases including cancer. Even though extensive work has been carried out to find an association between trace elements and cancer, and to understand the mechanisms involved in carcinogenesis, no definite conclusions are drawn so far (Rocha et al, 2007). Although trace elements Fe, Cu, and Zn are extremely common, assessment of their amounts is crucial for disease diagnostics.…”

Synchrotron radiation X-ray microfluorescence techniques and biological applications

“…The fluorescence mapping of iron, copper and zinc can be very important in diagnostics, because the biochemistry of these elements suggests that these metals may play important roles in carcinogenesis. But, the evidence linking iron, copper and zinc to cancer is far from conclusive and further research is needed [1]. Using X-ray fluorescence tomography the elemental map can be obtained without sample preparation.…”