There has been an interesting announcement from one of the teams at the TRIUMF national laboratory on the subject of medical isotope production. They are claiming that they have been able to produce a radioactive isotope known as Technetium-99m in a particle accelerator / cyclotron instead of a nuclear reactor. If there results hold up to scrutiny (which they should) and if it is economical, this could have a major impact on medical physics and on government policies on nuclear reactors.

Many people do not realize that when they are treated for cancers or some other health problems, they are exposed to a radioactive material. (They need not worry though, as the quantity is very small and very carefully delivered to its target with many safety features to prevent any other exposure). There are basically two reasons to use these isotopes – the radiation they give off can be tracked by imaging machines so that healthcare providers can study tumors or abnormal processes in the body, or the radiation can be directed into a tumor or other malignant cells to kill them with minimal damage to other parts of the body. The medical community has developed a reliance on radioactive isotopes for a number of common procedures now.

But there is a problem. Many of these isotopes can only be produced in nuclear reactors, which generate numerous types of radioactive material in large quantities, with most products not being useful at all. The reactors usually require something like uranium to start with – which obviously causes worries that someone will make a bomb out of it instead – and the byproducts of the reactor need to be dumped somewhere that they won't be disturbed for decades or centuries. Add in the problem that the isotopes should be used as quickly as possible before they decay away – and sometimes that can be only hours – and that nuclear reactors are large and expensive, so they cannot be placed in every hospital, and one sees that this source of isotopes is very difficult to manage.

The group lead by scientists at TRIUMF have developed an alternative production method. They placed molybdenum wafers inside a particle accelerator, and allowed high energy electrons to impact these targets. In this way, they can focus on a single nuclear reaction (or more realistically a small number of reactions) which convert the nuclei in the target into radioactive isotopes. This process produces little or no waste products compared to a reactor, and as a result poses no health risks if there is an accident. It also uses targets that cannot be converted into weapons, making it more politically acceptable. And perhaps the best part of the method is that apparently the energies are low enough that any cyclotron can generate the isotopes – including many already in use at universities and hospitals around the world.

In past articles I have always promoted the idea that high profile first announcements of experimental results are often wrong and should be questioned. While that is true, this experiment is more believable because the possibility has been known for decades. We know that we can convert lead into gold, but the price is more than the gold would be worth so we don't bother. So the idea of turning molybdenum into technetium is certainly plausible, although there are still going to be questions of how much can be produced and for what cost. The method won't get accepted obviously if it bankrupts a hospital to produce one dose! (Of course the other problem is that the government in Canada and the U.S. will both require years of testing to prove that the method is safe before it can actually be used)

For now though this is a major advance in both nuclear physics and medical physics. If this method can be implemented, it will mean that hospitals and universities can generate medical isotopes themselves without the inefficiencies of a large reactor. And that will certainly be a good thing for everyone!