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ST: Fachverband Strahlen- und Medizinphysik

ST 10: Basic and Applied Medical Physics (Poster Session)

ST 10.6: Poster

Mittwoch, 24. März 2010, 16:00–17:00, H41

Measurement technique for tracer kinetic studies with stable isotopes of cerium using thermal ionization mass spectrometry — •Teresa Keiser, Vera Höllriegl, Augusto Giussani, and Uwe Oeh — Helmholtz Zentrum München - German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany

The double tracer technique,introduced in the 60s, is a potent method to investigate the biokinetics of elements in humans and was modified and applied over the last years to various elements of interest for radiation protection in order to validate and improve the available biokinetic models of ICRP. One project currently running at Helmholtz Zentrum München aims at studying the biokinetics of cerium in humans using stable tracers. For this purpose a methodology needs to be developed which enables to measure simultaneously different stable cerium isotopes in human body fluids such as blood and urine. The measurement protocol was developed using cerium standard solutions and different combinations of filament materials measured with TIMS. Best results were achieved adopting the double filament configuration and using tantalum filaments. Under these experimental conditions the measured standard ratios agree within 1% with the IUPAC values. For measuring biological samples with TIMS a chemical treatment is necessary. A chemical method for eliminating all elements except cerium was established. The methodology was applied to biological samples collected during tracerkinetic studies in humans and preliminary results of urine excretion and plasma clearance of cerium will be presented.