Energy-dispersive x-ray microscopy to trace gadolinium in tissues

An electron microscopic technique, energy-dispersive x-ray (EDX) analysis, was applied to rat tissue specimens containing gadolinium diethylenetriaminepentaacetic acid (DTPA). EDX spectroscopy was able to detect the characteristic radiation spectra of gadolinium from tissues in concentrations as low as 0.005 mmol per gram of tissue. A mapping algorithm allowed the detected spectra to be assigned to a specific site of origin within the tissue. This technique allows direct vidualization of the location of Gd-DTPA complex in tissues.