Distribution of ytterbium-169 in rat brain after intravenous injection.

It is well known that lanthanides have come into extensive and rapid use in a number of fields. As a result, more and more lanthanides are getting into the environment and food chains. However, the distributions of lanthanides in brain are not yet very clear. In this study, adult Sprague-Dawley male rats were intravenously injected with 0.5 ml of 169YbCl3 solution (containing 10 microg Yb). The brains were perfused with saline to minimize the blood influence. The radioactivities of 169Yb in the five brain regions (hypothalamus, cerebellum, hippocampus, corpus striatum and cerebral cortex) were counted. The results suggested that Yb did enter into the brain. Though only about 0.005% of the given dose was accumulated in the brain, Yb seemed to remain in the brain for long time. The highest specific activities were observed in the hypothalamus, hippocampus and cerebellum.