X-Ray fluorescence microtomography under various excitation conditions

摘要

The main goal of this work is two-fold: (1) to compare three different excitation conditions in x-ray fluorescence microtomography (XRFCT) in the analysis of reference samples, and (2) to determine the elemental distribution map for breast tissue samples, in order to verify concentrations of certain elements correlated with characteristics and pathology, using x-ray transmission microtomography (CT). The experiments were performed at the X-Ray Fluorescence Facility (D09B-XRF) of the Brazilian Synchrotron Light Laboratory (LNLS), Campinas, Brazil. In this work, a multilayer monochromator with photon energies near 12 keV, a monochromatic beam at 9.8 keV using a Si (111) crystal, and the white beam were used for elements excitation of elements inside the sample. The sample was placed on a high-precision goniometer and translation stages, which allowed for rotation as well as translation perpendicular to the beam. Fluorescence photons were collected by means of an energy dispersive HPGe detector placed at 90 degrees to the incident beam, while transmitted photons were detected with a fast Na(TI) scintillation counter, placed behind the sample, in the direction of the incoming beam. Transmission CT images were reconstructed using a filtered back-projection algorithm, and XRFCT images were reconstructed using a filtered back-projection algorithm with absorption correction.