Derivation of elemental concentrations maps in a thin lamb bone sample from a two-dimensional synchrotron-based x-ray...

Objective.Microscopic two-dimensional (2D) elemental distributions of tissues can be probed by synchrotron-based 2D x-ray fluorescence (XRF) scanning. Converting 2D XRF data into elemental concentration maps (ECMs) enhances the scientific value of such studies by facilitating comparisons within the increasingly larger pool of published data. This study developed and tested a computationally fast method able to perform such conversions.Approach.A semicircular cortical bone slice, 0.38-mm-thick and ∼150 mm²in area, transversally sectioned from a lamb tibia was analyzed at the VESPERS beamline of the Canadian Light Source synchrotron. The 2D XRF scan consisted of short sequential microbeam irradiations in 10µm steps. The scan was repeated at four incident photon energies and probed two rectangular areas (0.24 mm²) at the sample's opposite edges. K-shell XRF peaks of seven elements (P, Ca, Fe, Ni, Cu, Zn, and Sr) were identified in the acquired x-ray spectra. Using physical and geometrical assumptions of the fundamental parameter method (FPM), the developed computer code generated ECMs of the investigated microscopic areas.Main Results.Generated ECMs indicated relatively uniform distributions of the seven chemical elements, with localized peaks near the sample edges. The average elemental concentrations at the four photon energies agreed with each other and compared well with literature data.Significance.A fast FPM-based computer code for converting 2D XRF data into ECMs was developed and tested. The code can be applied to investigations of other biological tissues extending the applicability of existing quantitative XRF methods.