Evaluation of ${}^{186}$WS${}_2$ target material for production of high specific activity ${}^{186}$Re via proton irradiation. Separation, radiolabeling and recovery/recycling

Enriched tungsten disulfide (${}^{186}$WS${}_2$) was evaluated at increasing proton beam currents (20–50 μA) and times (up to 4 h) on a GE PETtrace cyclotron for production of high specific activity (HSA) ${}^{186}$Re. The HSA ${}^{186}$Re was separated from the irradiated target as [${}^{186}$Re][ReO${}_4$]${}^{-}$ by a liquid–liquid extraction method and radiolabeled with a new N${}_2$S${}_2$ ligand (222-MAMA-N-ethylpropionate). The enriched ${}^{186}$W was recovered from the extraction process, analyzed for purity and enrichment, and converted back to the disulfide (${}^{186}$WS${}_2$). The results demonstrate that the ${}^{186}$WS${}_2$ is an easily pressed target material that can withstand relatively high currents and can be readily recovered and recycled. The ${}^{186}$Re produced was isolated in high specific activity and readily formed the radiotracers [${}^{186}$Re][ReO(222-MAMA-N-ethylpropionate)] and [${}^{186}$Re][Re(CO)${}_3$(OH${}_2$)${}_3$]${}^{+}$.