Producing radioisotopes using electron accelerators

Radioactive isotopes are an important tool in healthcare, both in diagnostics and in cancer treatment. The current production of several important isotopes in nuclear reactors is vulnerable, however, and produces high-level radioactive waste. Lighthouse, a new production method using electron accelerators, could become a good alternative. The technology emerged as a spin-off from a project by silicon chip machine manufacturer ASML. A consortium is currently being formed, in which the UG will participate, to develop applications for this technology. Due to its great potential and the importance of medical isotopes, the project has recently been declared a ‘National Icon’.

Medical radioisotopes are indispensable in today's healthcare. They are particles that emit radiation and are used in the detection of a large number of diseases and the treatment of, mainly, tumours.

Production problems

The most important radioactive isotope in medical diagnostics is technetium-99m. This isotope decays relatively quickly, exposing a patient to radiation only briefly. In order to obtain technetium-99m, molybdenum-99 is required as a parent isotope. However, there are several problems with the production of molybdenum-99, says Sytze Brandenburg, Professor of Accelerator Physics: ‘Seventy percent of world production takes place in outdated reactors from the 1960s, in Petten (the Netherlands) and Chalk River (Canada). If production falters there, shortages will occur within two weeks. Moreover, the production of radioactive isotopes in a reactor creates a relatively large amount of radioactive waste, which has to be stored for a very long time. Thus there is a clear need for the development of cleaner production methods for molybdenum-99 and other radioactive isotopes.’

Particle accelerator

Particle accelerators are often suggested as a solution in the search for alternative production methods. Brandenburg: ‘An accelerator can produce medical isotopes with a particle beam. But existing accelerators have a much more limited capacity than reactors, and the quality of the isotopes they produce is not yet optimal. In their current form, they are not generally a realistic alternative for reactors.’

The Veldhoven-based company ASML, however, discovered that the accelerator for a free electron laser, which they had been studying for a project on the development of a light source for their lithography machines, might be capable of producing molybdenum-99 and other radioactive isotopes of sufficient quality. ASML then started the Lighthouse project, performing a feasibility study together with external parties at home and abroad, including the UG. Brandenburg: ‘A great advantage of the accelerators for free electron lasers is the high intensity of the particle beam, which results in a substantially higher production capacity than existing accelerators have. A small number of these devices could cover the entire world production.’

Waste

Lighthouse, like conventional particle accelerators, has great advantages with regard to waste, although it would be a misunderstanding to think that no radioactive waste will be produced at all, Brandenburg warns: ‘Every material you irradiate becomes radioactive; for example, the cooling water and the small boxes holding the material. Accelerator waste can be limited by picking your materials strategically, however. Moreover, the waste has a limited life span, radiating for several decades at most. Reactors are a different story: the fission process produces irreversible, high-level radioactive waste with a life span of up to tens of thousands of years.’

Within reach

Brandenburg is enthusiastic about the new technology: ‘The idea is there, the technology available: it is a matter of implementing and scaling it up, no doubt with considerable technical challenges ahead. Heat production, for instance, is enormous, making proper cooling essential.’ ASML will not be developing the technology alone; a consortium is being formed in which the KVI-CART (Center for Advanced Radiation Technology) of the University of Groningen is one of the academic partners.

National Icon

Given its potential, the Lighthouse project has been declared one of three 2016 ‘National Icons’. The other winners are Blue Energy and Growboxx. As National Icons, these Dutch innovations receive government support. Each project will have a Minister or Secretary of State as its ambassador, facilitating access to a large national and international network. The projects also receive support in finding new partners and funding.

Information

• Prof.dr. Sytze Brandenburg (KVI-CART)
• www.nationaleiconen.nl