Whole body counting
Whole body counter ( engl.: whole body counter) are used to determine the activity and distribution of gamma-emitting nuclides in the living body (in vivo determination). The underlying measurement principle is the gamma spectrometry.
Purpose
Whole-body counters are used in radiation protection to monitor the recording ( incorporation) of radionuclides in people who deal with gamma-emitting unsealed radioactive materials and may be contaminated by food, by the inhalation of dusts and gases or through open wounds.
On the surface, the body adhering gamma emitters will inevitably be included in the measurement, so that the search for nuclides recorded can only begin once before and after cleaning the same activity is measured, which may necessitate multiple cleanings in a row. Only after this residual activity can be attributed solely to the incorporated lamps.
For use in hard to reach areas a whole body counter are also incorporated into the corresponding measurement vehicles.
Basis of the measurements
Measurements using this method are only possible if the radionuclides have been recorded, which emit gamma radiation ( α - and β - emitters are thus not measurable ). The gamma radiation is measured with several large, mostly mobile gamma detectors, and that allows both the amount of radiation and its energy distribution, the conclusions on each of incorporated nuclides. Even more accurate results this can provide measurements at intervals, from which the half-lives can be calculated, so that the nature of the incorporated radioactive nuclides can be from power distribution and associated half-life determined accurately. Body areas with intense radiation can be narrow; which allows conclusions to be drawn on which organs are affected.
The amount of gamma radiation is calculated from the count rates measured by the gamma detectors. When measured as a rule the results of all known detectors are added together. The energy distribution is obtained from the recorded spectra.
Whole body counter (eg lead ) surrounded by screens so that even very low activity can be detected that would otherwise be covered by the terrestrial environmental radiation. The despite the shield always remaining residual background radiation must be separately determined and subtracted from the measurement result.
Whole body counter in Germany, Austria and Switzerland
(Examples )
- National Institute for Occupational design Nordrhein-Westfalen, Dusseldorf
- Forschungszentrum Jülich
- Justus -Liebig- University Giessen
- University Hospital of Münster
- Hannover Medical School
- University of Cologne
- General Hospital of Vienna
- Seibersdorf Laboratories of the Austrian Institute of Technology ( Seibersdorf )
- University Hospital of Basel
- University of Lausanne
- Pedos AG, Switzerland
- Swiss National Accident Insurance Fund ( SUVA)