15th European Conference on X-Ray Spectrometry, Vienna, Austria, June 18-22, 2012
USTUR director, Sergei Tolmachev, was an author on a poster at the 15th European Conference on X-Ray Spectrometry in Vienna, Austria, June 18-22, 2012.
Elemental imaging of actinides in human tissues using LA-ICP-MS and SR micro-XRF
E. Vergucht, A. Izmer, B. De Samber, B Vekemans, K. Appel, S. Tolmachev, L. Vincze, F. Vanhaecke
The aim of this study was to evaluate the capabilities and limitations of two state-of-the-art approaches for elemental imaging of the distribution of actinides in human tissues in both a qualitative and a semi-quantitative manner. Human tissues were provided by the United States Transuranium & Uranium Registries (USTUR), which studies the uptake, the translocation and the biokinetics of actinides in humans [1]. Tissue sections from different USTUR cases (Registrants), which were occupationally exposed to certain actinides (U, Pu, Am), were investigated. Two highly sensitive analytical techniques were applied: Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Synchrotron Radiation (SR) micro X-Ray Fluorescence (micro-XRF) spectrometry. The latter was combined with complementary laboratory scanning micro-XRF measurements.
One of the investigated subjects (Case 1060) was occupationally exposed via inhalation to uranium. From this Registrant, parabronchial lymph node sections were made available by the USTUR. The LA-ICP-MS study showed that uranium is not homogenously distributed within the areas investigated, but is present under the form of micrometer-sized hot spots. Similar results were obtained from the SR micro-XRF experiments at beamline L, DESY, Hamburg. A semi-quantitative study of the LA-ICP-MS and SR micro-XRF elemental maps using a standard-based calibration curve revealed that the concentration of the uranium hot spots is within a similar range (up to ≈ 30 μg/g). In this case, detectable amounts of zirconium were found as well, also present in the form of microscopic aggregates.
Paratracheal lymph node sections from a second subject (Case 0407) were analysed for the presence of plutonium and americium. The LA-ICP-MS study revealed an inhomogeneous presence of plutonium under the form of microscopic hot spots. In addition, one ablated area possibly exhibited the presence of americium. The SR micro-XRF experiments confirmed that plutonium is present under the form of micrometer-sized heterogeneities. In addition, also amounts of zirconium and uranium were found, which were again distributed under the form of microscopic aggregates.
From the experiments performed in this study, it can be confirmed that both LA-ICP-MS and SR micro-XRF are very useful complementary techniques to study the distribution of actinides in tissue sections. LA-ICP-MS however, causes considerable damage to the sample, precluding a second measurement to be performed on the same sample area, which is not the case for (SR) micro-XRF experiments. [USTUR-0330-12A]
[1] United States Transuranium and Uranium Registries. Available from: http://www.ustur.wsu.edu/AboutUs/overview.html (Last access: 12 March 2012).