(March 18, 1994) The Lucas Heights research reactor in Australia and others like it around the world could soon be out of a job. According to Dr. Manuel Lagunas-Solar at the University of California, the cyclotron can produce commercially viable quantities of Technetium-99m, the most widely used isotope in nuclear medicine. (Story on Lucas Heights: WISE NC 398.3882)
(408.4037) WISE Amsterdam - Technetium-99m is produced indirectly in a reactor when its 'parent'isotope, molybdenum (Mo-99) is made. Molybdenum decays into our breaks down naturally into technetium over time. Of course, reactors emit radioactive pollution; storing wastes and disposing of the radio-active wastes generated is hazardous and costly; and besides, reactor produced medical isotopes are subsidized by the public purse because sales don't cover the costs of production.
Dr. Solar says the cyclotron can replace the reactor. In the cyclotron, electromagnetic fields accelerate moving sub-atomic particles around in circles until they reach sufficient speed to be allowed to lit targets of natural or enriched molybdenum.
The nuclear industry has known since at least the early 1970s that it could produce technetium-99m in this way, but argued it wasn't commercially viable. The early researchers used a particular variant of naturally occurring molybdenum known as the isotope Mo-100. They used the accelerator to bombard it with a proton. The proton was absorbed into the isotope's core but forced two neutrons out into the cold as it did so. The net result was the loss of one particle in the isotope's core transforming it directly into technetium. Neat, but not worth the trouble apparently.
Dr. Solar has found these researchers missed the significance of a second possible route using another natural molybdenum variant known as Mo-98. This involved using the accelerator to again hit the Mo-98 with a proton, but with the result that no neutrons are emitted, just a bit of gamma-radiation. This approach results in the Mo-98 increase by one to become the much sought after technetium-99m.
He believes that combining this approach with a state-of-the-art cyclotron would allow Australia to produce all the technetium it needs. He says the research and development stage is over and that developing the necessary technical procedures will only take two years.
The next phase is commercialization. This could take some time. At the recent reactor review, ANSTO, which runs Lucas Heights, argued that apart from the much-vaunted neutron scattering, HIFAR's (High Flux Australian Reactor) main purpose was the production of medical isotopes. So there are all the political obstacles to be overcome in persuading ANSTO and assorted politicians and bureaucrats (& similar authorities in the rest of the world) that nuclear reactors are no longer necessary for the commercial production of medical isotopes.
The report of Dr. Manuel C. Lagunas-Solar, Ph.D. is called: Production of Tc-99m and Mo-99 for Nuclear Medicine Applications via Accelerators as an Option to Reactor Methods. Oct. 1993 at the Crocker Nuclear Laboratory, University of California.
Source: The Third Opinion (Austr.), summer (southern-hemisphere) 1994, page 10.
Contact: Murray Matson, Movement Against Uranium Mining, P0 Box K133, Haymarket 2000, Sydney, Australia. Tel: +61 2 212 4538; Fax: +612 281 5216. Email: peg:foesydney (attn. Murray Matson)