The measurement of activity contained in a 32P stainless-steel stent by destructive assay

Destructive assays of stainless-steel stents containing 32P were performed. Prior to assay, 24 stents were intercompared on a NaI(Tl) well-type crystal. A subset of stents were then digested in a suitable carrier solution by the addition of concentrated hydrofluoric acid. The final solution was measured by the CIEMAT/NIST tritium efficiency tracing method for liquid scintillation counting. A separate experiment was performed which indicated no loss of activity during stent digestion. Expanded (k=2) uncertainties on stent activity ranged from 1.0% to 2.6%.