The gel generator: a viable alternative source of 99mTc for nuclear medicine

The majority of the worldʹs supply of 99mTc is derived from generators in which fission produced 99Mo is adsorbed on to alumina. While such systems consistently produce 99mTc with excellent physico-chemical and biomedical properties, their manufacturing processes, commencing with the irradiation of 235U, involve numerous complications with the result that few organisations, worldwide, are willing to participate in such an endeavour, despite the size of the market (> $US 100,000,000 per annum). Encouraging results from basic research on an alternative generator system, based upon zirconium molybdate gel prepared from neutron irradiated molybdenum trioxide, was the stimulus for the decision to build a small pilot plant at Lucas Heights to manufacture the new generator under conditions akin to routine production. From this series of generators, a database of comprehensive performance characteristics has been constructed to show that, indeed, (n, γ) 99Mo can be successfully exploited to provide an acceptable source of 99mTc for use in both nuclear medicine clinics and centralised radiopharmacies.