A representation of the clinically approved BNCT system in Japan

“FBPA is important because it confirms to doctors that a tumour has absorbed a boron containing compound and is ready for BNCT. Without it, the therapy may not work. As BNCT becomes more widely available, we’re going to need cyclotrons to meet FBPA demand,” said Amirreza Jalilian, a radioisotope and radiopharmaceutical chemist at the IAEA. A cyclotron is a type of particle accelerator that produces radioisotopes used in nuclear medicine by firing a particle beam at stable isotopes. The interaction results in a nuclear reaction that creates short-lived radioisotopes. Because these radioisotopes decay quickly, they need to be produced near or on the site where treatment takes place and used right away.

Jalilian notes that, although the number of research reactors used in the production of radioisotopes is rather stable, new, versatile and increasingly affordable cyclotrons are on the rise worldwide. Many of the shortlived radioisotopes used in patients can be produced by cyclotrons in hospitals, and that is a major advantage for the technology.

The radiopharmaceutical fluorodeoxyglucose is just one example. It relies on 18F, which can be produced with cyclotrons. That radiotracer is used in around 95 per cent of PET–CT procedures, and so is critical in neuroimaging and diagnosing cancer.

Another workhorse among radiopharmaceuticals is gallium-68 (68Ga), which is the key component of some theranostic radiopharmaceuticals — a type of pharmaceutical that uses radioisotopes both for diagnosis and therapy through the release of radiation. Such radiopharmaceuticals play an important role in diagnosing and following up on cancers, and shows particular promise in addressing prostate cancer. Producing 68Ga, however, does have its challenges.

“Today, the most common method for producing 68Ga is with a non-accelerator system called a generator, but generators simply cannot produce enough to meet demand. Cyclotrons offer an effective alternative means of direct production and are already greatly expanding the availability of 68Ga,” said Jalilian, explaining that ten centres around the world are now routinely using cyclotrons to produce 68Ga. The IAEA is currently coordinating a research project to support the exchange of international expertise in cyclotron-based production of 68Ga, and in 2019 released Gallium-68 Cyclotron Production, a publication dedicated to the topic.