A novel 99mTc delivery system using (n,γ)99Mo adsorbed on a large alumina column in tandem with Dowex-1 and AgCl columns

Mo-99 of specific activity 7.4-14.8 GBq (200-400 mCi)/g was adsorbed on a 'jumbo' alumina column (40 g. ;90 mm(H) x 20 mm (dia.): 50 g. 65 mm (H) x 35 mm (dia.). [Tc-99m] TcO4-, eluted with 50-70 ml normal saline and applied to a tiny column of a strong anion exchanger. Dowex-1 x 8, 10-15 mg. 8-12 mm (H) x 1 mm (dia.). Pertechnetate was eluted from the Dowex-1 column with 5-6 nil of 0.2 M NaI followed by washing with 1.5-1.8 ml water. Iodide was removed from this eluate by passage through a 1 g AgCl column (12 mm (H) x 8 mm (dia.)). The final product, pertechnetate, was recovered in 6.5-7.8 ml. while the NaCl content was close to that of normal saline. Each elution operation was complete in similar to45 min. The mean practical yield was similar to86% (n = 5), Closed cycle operation with sterile connecting tubes and multi-way stop-cocks was practised. The quality of the [Tc-99m]NaTcO4 thus obtained complies with the specifications applicable for radiopharmaceutical use. The major merit over other post-elution concentration methods is that the new procedure can function nearly independently of the volume of the primary eluate (in normal saline) from the alumina column generator (ACG). Tc-99m generators containing as much as 80-100 g alumina for holding 14.8-18.5 GBq (400--500 mCi) Mo-99 (at the reference time) are feasible using similar to15 mg Dowex-1 bed mass. A relatively user-friendly-cum-producer-friendly Tc-99m generator system has been demonstrated making use of the inexpensive and easy to prepare (n,y)Mo-99. The method is also applicable for the more costly W-188-Re-188 generator. Published by Elsevier Science Ltd.