The first useful application of fusion reactors may be to create radioactive isotopes for cancer treatment or medical imaging rather than to generate energy, claims a UK start-up firm.
快猫短视频s and engineers have worked on building a fusion reactor for a century, and a practical fusion power station is still thought to be decades away.
But is working on tiny fusion reactors that don鈥檛 attempt to generate large amounts of power, or even to equal the amount of electricity needed to run them. Instead, they will create radioactive isotopes, which are used for a range of medical applications and are difficult and expensive to source.
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Radioactive isotopes are used in two main ways in medicine: for killing cancer cells in radiotherapy and as radioactive tracers in the body to help spot medical conditions through imaging. Many of these isotopes have short half-lives, often just hours, so can鈥檛 be stockpiled and must be created, transported and used quickly.
The source of these isotopes 鈥� which are essentially versions of atoms with a different number of neutrons 鈥� is a handful of more conventional fission nuclear reactors around the world. Because selling these samples is much less lucrative than running a large, modern reactor for power, and there are lots of regulatory and safety hurdles to overcome in pulling samples from a reactor, it tends to be older sites or research devices that have made isotope production their niche.
The isotopes are produced by exposing certain elements to neutron bombardment inside the reactor, changing their nuclei by adding one or more of those neutrons, and then capturing the resulting isotopes.
A UK government report in 2017 showed that of the world鈥檚 medical isotope supply, and that all but one of these will shut down by 2030.
Astral Systems is aiming to build small fusion reactors that could be installed in regional isotope factories around the UK and globally, providing cheaper radioactive samples on a more flexible timeline.
The firm will use its reactors, which can already sustain fusion reactions, to produce neutrons to bombard other elements and create the isotopes. The idea is to begin creating iodine-131, lutetium-177 and later actinium-225, but the firm will have to go through clinical trials before the isotopes can be used in medicine, says , a co-founder of Astral Systems.
Wallace-Smith says he recently spoke to UK National Health Service staff at a conference about isotopes. They told him they had a shipment of isotopes, with a half-life of around a week, held at the border in Calais, France. 鈥淓very week the isotope decays, so there鈥檚 only half of it left. That package got held up for over a week, or two weeks, and then it was basically unusable as medicine. The more people that you talk to, the more issues you find out about,鈥� he says.
Isotope production techniques need to go through regulatory approval just as a new medicine would, says at King鈥檚 College London. There will be hurdles to overcome before they can be sold as medical products. And the quality of the isotopes produced will need to be tested and regulated. The UK Department of Health and Social Care didn鈥檛 respond to questions about the sale of isotopes in the UK.
Young says the worldwide supply chain for isotopes is fragile and the UK isn鈥檛 in the best position since leaving the European Union because it has no suitable reactor of its own and struggles to source material ahead of other countries.
鈥淲e鈥檙e no longer in the EU, and we don鈥檛 pay as much as the US,鈥� she says. 鈥淪o we end up at the bottom of the queue sometimes. That does mean that we鈥檝e had weeks, even during this year, where we haven鈥檛 had access to radioisotopes and so NHS trusts haven鈥檛 been able to do the regular nuclear medicine scans. So either they just scan very high-priority patients, but not as many, or they have to delay people, or people just don鈥檛 get access.鈥�
