Detection of mercury in the kidney via source‐excited x‐ray fluorescence

Non‐invasive detection of kidney Hg in vivo is important in order to prevent detrimental health effects in occupationally exposed persons. In this study, preliminary results of a 109 Cd source‐based x‐ray fluorescence system for the detection of Hg in the kidney are presented. The system includes a single 50 mm diameter HPGe detector with a 109 Cd source mounted on the detector face for backscatter measurement geometry. A detection limit of 3.9 ppm was obtained during a bare kidney phantom feasibility study. In order to simulate an in vivo measurement, kidney phantoms were also placed inside a water tank representing the torso. The detection limit was 5.0 ppm at 1 cm phantom depth, as measured to the phantom boundary. As expected, Hg sensitivity decreased with kidney depth owing to the attenuation of incident 109 Cd γ‐rays and emitted characteristic Hg K x‐rays, so that at a phantom depth of 4 cm the detection limit was 44 ppm. Further improvements to the detection limit will allow future in vivo kidney Hg measurements of chronically exposed workers. Copyright © 2007 John Wiley & Sons, Ltd.