Comparison of the biodistribution of 153Gd-labeled Gd(DTPA)2-, Gd(DOTA)-, and Gd(acetate)n in mice.

The biodistributions of 153Gd-labeled Gd(DTPA)2-, Gd(DOTA)-, and Gd(acetate)n were determined in mice at five residence times. Gd(DTPA)2- and Gd(DOTA)- had similar distributions with greater than 89% renally excreted in 1 h. At 7 days and longer after Gd(DTPA)2- administration, 153Gd bone levels were higher than could be attributed to free 153Gd3+, suggesting that Gd(DTPA)2- dechelates in vivo. Gd(DOTA)- did not appear to dechelate. Gd(acetate)n did not readily clear and 153Gd levels remained high in liver, lungs, and spleen for 28 days.