Accumulation and distribution of samarium-153 in rat brain after intraperitoneal injection

It is well known that rare earth elements (REEs) have come into extensive use in a number of fields. As a result, REEs are becoming closely related to human's daily life. However, until now, the distributions of REEs in the brain are not yet very clear. In this study, Sprague-Dawley male rats were intraperitoneally injected with 0.25 mL of (153)SmCl(3) solution (containing 10 microg Sm). The brains were perfused with saline to minimize the blood influence. The radioactivities of (153)Sm in the five brain regions (hypothalamus, cerebellum, hippocampus, corpus striatum, and cerebral cortex) were counted. The results suggested that Sm did enter into the brain. Although only about 0.0003% of the given dose was accumulated in the brain, Sm seemed to be remain in the brain for a long time. The highest amounts and lowest concentrations of (153)Sm were found in the cerebral cortex, and the highest concentrations of (153)Sm were found in the hypothalamus.