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

Introduction: Preparation of clinical-scale Mo-99/Tc-99m generator using (n,gamma) activated low specific activity Mo-99 and nanocrystalline gamma-Al2O3 as a high capacity sorbent matrix is attempted. Methods: Nanocrystalline gamma-Al2O3 was synthesized by 'solid state mechanochemical' reaction of aluminum nitrate with ammonium bicarbonate. Experimental parameters were optimized to effectively separate Tc-99m from Mo-99 using this sorbent as the column matrix. The performance features of a 13 GBq (350 mCi) Mo-99/Tc-99m generator using this sorbent and Mo-99 produced by (n,gamma) route having specific activity 12.9-18.5 GBq/g were evaluated for 10 days. Results: The sorbent possessed the requisite selectivity for Mo-99 and demonstrated a maximum sorption capacity of 200 +/- 5 mg Mo/g, which is similar to 10 times higher than that of ordinary acidic alumina. The overall yield of Tc-99m was >80%, with radionuclidic purity >99.99% and radiochemical purity >99%. The yield of Tc-99m varied from 7.8 to 2.1 GBq in the eluate for the six days of operation of the generator. The radioactive concentration of Tc-99m eluted was adequate for the formulation of radiopharmaceuticals. The performance of the generator remained consistent over an extended period of 10 days. The eluted Tc-99m was suitable for the formulation of Tc-99m-DMSA and Tc-99m-EC resulting in high radiolabeling yields (>98%). Conclusion: The effectiveness of gamma-Al2O3 as a new generation sorbent in the development of clinically useful Mo-99/Tc-99m generator using low specific activity Mo-99 and yielding Tc-99m with adequate radioactive concentration and high purity suitable for formulation of radiopharmaceuticals is demonstrated. (c) 2012 Elsevier Inc. All rights reserved.