Preparation of clinical-scale 99Mo/99mTc column generator using neutron activated low specific activity 99Mo and nanocrystalline γ-Al2O3 as column matrix

IntroductionPreparation of clinical-scale 99Mo/99mTc generator using (n,γ) activated low specific activity 99Mo and nanocrystalline γ-Al2O3 as a high capacity sorbent matrix is attempted.MethodsNanocrystalline γ-Al2O3 was synthesized by ‘solid state mechanochemical’ reaction of aluminum nitrate with ammonium bicarbonate. Experimental parameters were optimized to effectively separate 99mTc from 99Mo using this sorbent as the column matrix. The performance features of a 13 GBq (350 mCi) 99Mo/99mTc generator using this sorbent and 99Mo produced by (n,γ) route having specific activity 12.9–18.5 GBq/g were evaluated for 10 days.ResultsThe sorbent possessed the requisite selectivity for 99Mo and demonstrated a maximum sorption capacity of 200 ± 5 mg Mo/g, which is ~ 10 times higher than that of ordinary acidic alumina. The overall yield of 99mTc was > 80%, with radionuclidic purity > 99.99% and radiochemical purity > 99%. The yield of 99mTc varied from 7.8 to 2.1 GBq in the eluate for the six days of operation of the generator. The radioactive concentration of 99mTc eluted was adequate for the formulation of radiopharmaceuticals. The performance of the generator remained consistent over an extended period of 10 days. The eluted 99mTc was suitable for the formulation of 99mTc-DMSA and 99mTc-EC resulting in high radiolabeling yields (> 98%).ConclusionThe effectiveness of γ-Al2O3 as a new generation sorbent in the development of clinically useful 99Mo/99mTc generator using low specific activity 99Mo and yielding 99mTc with adequate radioactive concentration and high purity suitable for formulation of radiopharmaceuticals is demonstrated.