Abstract
The availability of technetium-99m (99mTc) for single-photon imaging in diagnostic nuclear medicine is crucial, and current availability is based on the molybdenum-99 (99Mo)/99mTc generator fabricated from fission-based molybdenum (F 99Mo) produced by use of highly enriched uranium (HEU) targets. The use of HEU targets is being phased out because of risks related to nuclear material proliferation, so alternative strategies for production of both 99Mo and 99mTc are being evaluated intensely. There are evidently no plans for replacement of the limited number of reactors that have primarily provided most of the 99Mo. The uninterrupted, dependable availability of 99mTc is a crucial issue. For these reasons, new options being pursued include both reactor- and accelerator-based strategies to sustain the continued availability of 99mTc without the use of HEU. In this paper the scientific and economic issues for transitioning from HEU to non-HEU are also discussed. In addition, the comparative advantages, disadvantages, technical challenges, present status, future prospects, security concerns, economic viability, and regulatory obstacles are reviewed. In addition, the international actions in progress towards evolving possible alternative strategies to produce 99Mo and/or 99mTc are analyzed. The breadth of technologies and new strategies under development to provide 99Mo and 99mTc reflects both the broad interest in and the importance of the pivotal role of 99mTc in diagnostic nuclear medicine.