Exploitation of Nano Alumina for the Chromatographic Separation of Clinical Grade 188Re from 188W: A Renaissance of the 188W/188Re Generator Technology

The W-188/Re-188 generator using an acidic alumina column for chromatographic separation of Re-188 has remained the most popular procedure world over. The capacity of bulk alumina for taking up tungstate ions is limited (similar to 50 mg W/g) necessitating the use of very high specific activity W-188 (185-370 GBq/g), which can be produced only in very few high flux reactors available in the world. In this context, the use of high-capacity sorbents would not only mitigate the requirement of high specific activity W-188 but also facilitate easy access to Re-188. A solid state mechanochemical approach to synthesize nanocrystalline gamma-Al2O3 possessing very high W-sorption capacity (500 mg W/g) was developed. The structural and other investigations of the material were carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer Emmett Teller (BET) surface area analysis, thermogravimetric-differential thermal analysis (TG-DTA), and dynamic light scattering (DLS) techniques. The synthesized material had an average crystallite size of similar to 5 tun and surface area of 252 10 m(2)/g. Sorption characteristics such as distribution ratios(1(K-d), cagacity, breakthrough profile, and elution behavior were investigated to ensure quantitative uptake of W-188 and selective elution of Re. A 11.1 GBq (300 mCi) W-188/Re-188 ice generator was developed using nanocrystalline gamma-Al2O3, and its performance was evaluated for a period of 6 months. The overall yield of Re-188 was >80%, with >99.999% radionudidic purity and >99% radiochemical purity. The eluted 188 Re possessed appreciably high radioactive concentration and was compatible for the preparation of Re-188 labeled radiopharmaceuticals.