DOSE-DEPENDENT BIODISTRIBUTION OF [GD-153]GD(ACETATE)N IN MICE

[Gd-153]Gd(acetate)n was administered i.v. to mice to study the effect of dose on the distribution of free Gd. Distribution from blood was s low with the majority of the Gd distributing in the liver. Gd saturate d in bone. Heart, lungs, kidneys, brain and skeletal muscle exhibited time-dependent decreases in Gd concentration. Gd that washed out of he art, lungs, kidneys and/or muscle redistributed in liver, spleen and f emur. These results indicate a complex dose- and time-dependent tissue distribution for Gd and emphasize the importance of eliminating unche lated free Gd as a contaminant in Gd-chelates before testing in biodis tribution experiments. The long-term residual accumulation of Gd sugge sts the need to minimize Gd-chelate dissociation in vivo.