title: Quantitative comparison of preparation methodologies for X-ray fluorescence microscopy of brain tissue.
abstract: X-ray fluorescence microscopy (XFM) facilitates high-sensitivity quantitative imaging of trace metals at high spatial resolution over large sample areas and can be applied to a diverse range of biological samples. Accurate determination of elemental content from recorded spectra requires proper calibration of the XFM instrument under the relevant operating conditions. Here, we describe the manufacture, characterization, and utilization of multi-element thin-film reference foils for use in calibration of XFM measurements of biological and other specimens. We have used these internal standards to assess the two-dimensional distribution of trace metals in a thin tissue section of a rat hippocampus. The data used in this study was acquired at the XFM beamline of the Australian Synchrotron using a new 384-element array detector (Maia) and at beamline 2-ID-E at the Advanced Photon Source. Post-processing of samples by different fixation techniques was investigated, with the conclusion that differences in solvent type and sample handling can significantly alter elemental content. The present study highlights the quantitative capability, high statistical power, and versatility of the XFM technique for mapping trace metals in biological samples, e.g., brain tissue samples in order to help understand neurological processes, especially when implemented in conjunction with a high-performance detector such as Maia.
authors.affiliation: Materials Science and Engineering and the Preventative Health Flagship, CSIRO, Gate 5, Normanby Road (Private Bag 33, Clayton South 3169), Clayton, VIC 3168, Australia. simon.a.james@csiro.au
authors.forename: Simon A
authors.initials: SA
authors.lastname: James
authors.forename: Damian E
authors.initials: DE
authors.lastname: Myers
authors.forename: Martin D
authors.initials: MD
authors.lastname: de Jonge
authors.forename: Stefan
authors.initials: S
authors.lastname: Vogt
authors.forename: Chris G
authors.initials: CG
authors.lastname: Ryan
authors.forename: Brett A
authors.initials: BA
authors.lastname: Sexton
authors.forename: Pamela
authors.initials: P
authors.lastname: Hoobin
authors.forename: David
authors.initials: D
authors.lastname: Paterson
authors.forename: Daryl L
authors.initials: DL
authors.lastname: Howard
authors.forename: Sheridan C
authors.initials: SC
authors.lastname: Mayo
authors.forename: Matteo
authors.initials: M
authors.lastname: Altissimo
authors.forename: Gareth F
authors.initials: GF
authors.lastname: Moorhead
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Wilkins
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002857:Chromium / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D008856:Microscopy, Fluorescence; D009532:Nickel / Q000737:chemistry; D051381:Rats; D014025:Titanium / Q000737:chemistry; D028561:Transition Elements / Q000737:chemistry; D014965:X-Rays
chemical_list: D028561:Transition Elements; D002857:Chromium; D009532:Nickel; D014025:Titanium; D007501:Iron