¹⁶⁹Yb-cisdichlordimethionine platinum (PtCl₂Meth₂) is an oncophilic radiopharmaceutical, particulary useful in staging and monitoring the therapy of malignant lymphomas. The paper estimates the risk related to application of the compound, by calculating the organ doses delivered per unit administered activity and the resulting effective dose. The knowledge of the kinetics of retention of the radioactive substance in individual organs and its excretion from the body, is based on data obtained from controlled experiments with serial sacrifice of rats and comparison with the data obtained from comparative measurements in man (whole body retention and excretion rate via the dominant excretory route). Such procedure makes interspecies extrapolation from animals to man less insecure than direct application of the kinetics in the animals studied to the behaviour of the substance in man.
The biokinetics of ¹⁶⁹Yb-PtCl₂Meth₂ seems to be different from that of other compounds of the lanthanide and actinide elements. The main difference consists in much higher urinary elimination of the radiopharmaceutical, that leads to much lower whole body retention.
The estimated value of the effective dose per unit injected activity, E = 0.20 ± 0.02 mSv, and per diagnostic procedure in man, E = 37.4 ± 2.7 mSv, is acceptable in oncological diagnostics.