The many uses of cyclotrons
The radioisotopes in radiopharmaceuticals are commonly used to produce images of organs or tissues, to detect diseases and help visualise the growth and shrinking of tumours.
The most prevailing radioisotopes produced through cyclotrons are those that have short half-lives, meaning they lose much of their radioactivity within a few hours and are therefore not suitable for long transport times. These include fluorine-18, carbon-11, oxygen-15 and nitrogen-13 for an imaging technique called positron emission tomography (PET). PET is used to produce high-quality 3D images of target organs or cells in the body to diagnose disease. Hospitals in Portugal, a country of just 10 million, perform over 50,000 PET procedures per year. Globally, cyclotrons account for 95 per cent of the production of radiopharmaceuticals used in PET.
These include radiopharmaceuticals whose production had been cumbersome before the involvement of cyclotrons.
Gallium-68 (Ga-68), for instance, has predominately been produced by a ‘generator’, which can be used for only one year and can create only enough of the radionuclide to cover diagnosis of four to six patients a day. Using cyclotrons, Ga-68 can be produced for up to around 20 patients per day and at a lower cost. At least 10 centres worldwide are now using this approach. The IAEA’s publication, Gallium-68 Cyclotron Production, and a coordinated research project is supporting exchange of international expertise in cyclotron-based production of Ga-68.
The IAEA is also formulating guidelines to enhance and strengthen the use of zirconium-89 (Zr-89), a PET radioisotope with a relatively long half-life of 3.3 days in comparison to the half-life of flurorine-18 which only lasts one hour and 50 minutes. Zr-89’s half-life provides enough time to be used by medical practitioners to closely observe how molecules in the body behave. It is also applied in clinical trials to detect anti-bodies when a patient is going through cancer therapy.
