Effect of time on the determination of the clearance rates of insoluble plutonium 239 oxide
Métivier, H.; Masse, R.; Nolibé, D.; Lafuma, J.
Health Physics 32(5): 447-450
1977
ISSN/ISBN: 0017-9078 PMID: 407176 Document Number: 111017
When measurements of Pu lung burdens are carried out by external counting methods it seems difficult to improve fitting because results are highly scattered. The intermediate clearance is ignored and risks might be underestimated. When half-time values are more than 500 days, it is difficult to give accurate results if duration of measurements is too short. There are no theoretical and physiological grounds for a 3-compartment model rather than for a model with any number of compartments. The present data from baboons indicated that there is a continuous decrease of the particular excretion rate. Such an effect has already been described by W.J. Bair in a study on beagles. Comparison of non-toxic particles (51Cr labelled latex particles) and highly toxic 239PuO2 particles shows that in both cases a very slowly excreted compartment exists in the deep lung independently of the particle toxicity. An intermediate phase between this compartment and the rapidly cleared out tracheobronchial one apparently exists. This phase is cleared by dose-dependent mechanisms. Whether this phase can be described by a single compartment has yet to be determined.