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 ¹⁵³SmCl₃ solution (containing 10 μg Sm). The brain were perfused with saline to minimize the blood influence. The radioactivities of ¹⁵³Sm 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 ¹⁵³Sm were found in the cerebral cortex, and the highest concentrations of ¹⁵³Sm were found in the hypothalamus.