An analysis of the retention of plutonium by the tissues of the rat.

The amount of plutonium-239 in the blood, six bones, the kidneys, and the liver of male rats was measured at 18 different intervals of time between 5 min and 1 yr after a single intravenous injection of 0.1 μCi ${}^{239}{\rm Pu}/{\rm kg}$ rat as plutonium citrate. The data collected have been used to obtain models for the retention of plutonium by an organ. The rate of transfer of plutonium from blood to bone was found to depend simply on the amount of plutonium in the blood, but the rate of transfer of plutonium from blood to the soft organs involved plutonium in three species, each species being transferred at a characteristic rate that led to a triphasic exponential equation for the retention of plutonium by blood.