Age-related biokinetics of cerium-141-chloride in rats

Absorption and retention of Ce141-chloride in adult and juvenile rats were measured by gamma counting of the total body, organs, tissues and parts of the carcass. Different fractions of Ce141 in the total body as well as in bone and liver were seen for the various age groups, particularly in sucklings. Autoradiographs did not reveal incorporation of Ce141 into histological structures. In contrast to the fractional distribution of 0.6 and 0.2 to liver and bone as stated in ICRP 30 for cerium, reversed fractions were measured in the youngest juvenile group 20 days after administration. The fractional absorption of cerium was shown to be higher by a factor of hundred in sucklings compared to adults. This is in accordance with considerations in radiation protection for members of the public, taking into account a variability of two orders of magnitude for the absorption of poorly absorbed radionuclides. 9 refs.; 7 figs.; 2 tabs