Radioisotope concentration effect in biology: its consequences in the use of radioactive tracers
Experiments with people inhaling mixtures of stable and radioactive senon ($sup 133$Xe) showed a radioisotope concentration effect (RICE): if, under the same conditions, various amounts of radioxenon mixed with a fixed amount of stable xenon are inhaled the whole-body activity (A/sub t/) of $sup 133$Xe at any time t after inhalation is never proportional to the inhaled activity (I), as it should be on the hypothesis of identical behaviour of stable and radioactive xenon in the body. The experimental relationship can be described by a power function of the type: A/sub t/(I) = k I/sup r/, where the exponent r is less than 1, for all t. This RICE has two important consequences for using radioactive tracers in biology. These consequences were experimentally confirmed with rats inhaling radioxenon mixtures, and with tomato plants absorbing stable and radioactive caesium from solutions: for simultaneous intake of two radioisotopes of the same element, the bigger the concentration ratio of the two radioisotopes in the intake, the bigger the relative difference between the two biological retentions of these radioisotopes; for simultaneous intake of the radioisotope and the stable isotope of the same element under identical conditons, the biological absorption of the radioisotope may be different from the biological absorption of the stable isotope, the differences depending on the relative concentrations of the isotopes. (auth)
- Research Organization:
- EURATOM, Brussels
- NSA Number:
- NSA-33-007618
- OSTI ID:
- 4155942
- Country of Publication:
- IAEA
- Language:
- English
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Related Subjects
*PLANTS-- RADIONUCLIDE KINETICS
*RADIOISOTOPES-- BIOLOGICAL RADIATION EFFECTS
*RATS-- RADIONUCLIDE KINETICS
*XENON 133-- INHALATION
560172* --Biomedical Sciences
Applied Studies--Radiation Effects--Nuclide Kinetics & Toxicology--Animals
CESIUM ISOTOPES
N48720* --Life Sciences--Nuclide Kinetics & Toxicology-- Animals
N48730 --Life Sciences--Nuclide Kinetics & Toxicology--Plants
RETENTION
TRACER TECHNIQUES
XENON ISOTOPES