OPM-MEG: A revolution in brain imaging technology

“It’s such a cool piece of technology! It’s like having a cloud on your head. It’s really nice,” says Liberty.

Mum Rachel is watching 17-year-old daughter Liberty model what looks like a trendy cycle helmet covered in latticework and holes. On a screen Liberty’s brainwaves are tracked to the exact millisecond as she moves and talks.

This wearable technology is a far cry from the invasive intracranial scans Liberty needed after she was diagnosed with epilepsy at age four.

“What we’re doing here is a world first. It’s a brain scanner you can wear. And that’s very different from a brain scan that’s typically a tube you get jammed into. It has changed the way we think about the brain and how the brain works, and it’s allowed us to scan the brain in its natural environment. It’s a big breakthrough for neuroscience.”

Gareth Barnes, head of magnetoencephalography at University College London, has spent the last decade working with Nottingham University’s head of physics Matt Brookes. Together, they have been developing the optically pumped magnetometer-magnetoencephalography (OPM-MEG): a wearable brain scanner. Initially aimed at children with epilepsy, it also comes with a remarkable number of unprecedented potential applications across medicine, military and sport.

It was developed as an alternative for invasive, intracranial electroencephalograms (EEGs) and traditional magnetoencephalography (MEG), which Gareth describes as "a very big one-size-fits-all thermos flask into which everybody’s head has to fit".

Traditional MEG requires cryogenic conditions of minus 269°C for the magnetic field detectors to operate.

“That places a lot of limitations. You can't get them very close to the head because of the low temperature, so they have to be kept a relatively long way away. They have to be kept behind a vacuum, again for thermal insulation, and they also need to be in a rigid shell,” says Matt.

If a patient moves their head, it blurs the magnetic field. For children, whose smaller heads are proportionally further away from the sensors, there is even lower sensitivity. And of course, it’s very difficult for children to stay still throughout the entire process. MEGs are also extremely expensive to buy and run.

“Epilepsy is a tough gig,” says mum Rachel. By the time Liberty was seven she was having 30 seizures a day. Rachel recalls: “The toughest bit was the diagnostic part – the intracranial EEG – where they were trying to find exactly where the lesion was. They take a piece of skull off, and wire into the brain. That was probably the hardest bit: ten days sitting in a bed with these long wires in her brain, reading the EEG results and testing all the time. That was a lot to go through.”

The technology behind OPM-MEG has an unexpected origin. In the early 2000s, US scientists were working on making atomic clocks smaller, cheaper and more widely available. They discovered they could use atomic clock components to measure very small magnetic fields from the brain. It was an important step towards a new generation of super-precise measurement devices called quantum sensors that could operate without cryogenic temperatures. This meant they had the potential to become small, portable and flexible.

That potential drew the attention of Matt and Gareth. “My team did some simulations on what might be possible and the results were so exciting we went to London and took the results to Gareth. He was very excited too, and that's how we got started,” says Matt.

In 2025 the pair were ready to unveil their wearable scanner to the world. It’s a piece of engineering brilliance – sensors not much larger than a thumbnail in holes around a 3D-printed helmet that can be scaled to fit babies, children and adults. Each sensor is meticulously wired into a backpack worn by the patient inside a magnetically shielded room. People are free to move naturally as the brain scan takes place. It’s remarkably precise due to the sensors’ proximity to the brain.

Further development and regulatory approval is needed before the wearable scanners can move beyond specialist centres into wider use, but the clinical potential is significant.

“This technology is potentially most impactful on children,“ Gareth says. “Children not only have small heads, but they also find it difficult to stay still within a conventional scanner. For that reason, children are often not scanned until they're about 18 years old, which can mean they don't get their surgery until they are adults, by which time their education is finished.

“Treating epilepsy earlier, or operating earlier, would be a big advantage to these children, and that's what this technology might allow."

“I think it will offer enormous hope because it’s such a slow process otherwise: doing all the diagnostic tests, waiting for results, the results aren’t clear, so it’s back to the drawing board. It’s a really long process. Anything that can speed that up will be amazing,” says Rachel.

In 2016, armed with a toy building block to show Wellcome the size of the sensors they wanted to achieve, Gareth and Matt applied for funding. Wellcome awarded them a five-year collaborative grant.

“That longevity of funding enabled us to get from an initial prototype to where we are now, which is something that can actually be used routinely for neuroscientific discovery,” says Gareth.

Additional support from Wellcome included:

• Support for UCL Wellcome Centre for Human Neuroimaging – which provided mathematical modelling, tried-and-tested frameworks for neuroscientific experiments (experimental paradigms) and neuroimaging expertise that turned raw quantum sensor data into high-resolution brain maps.
• Support for early validation of the prototype – meaning the team were able to successfully demonstrate OPM-MEG as a platform for neuroscientific investigation. This led to follow-up funding for the UCL and Nottingham groups, and broader adoption of the technology by research laboratories worldwide.
• Supporting lived experience research to shape clinical use – including the UK’s first dedicated paediatric OPM-MEG clinic at the charity Young Epilepsy. This took the technology out of physics labs and placed it directly into diagnostic suites to help map the brains of young children facing complex epilepsy surgeries.

The unprecedented insights that OPM-MEG offers into the human brain is attracting worldwide attention from researchers, clinicians and scientists.

Academic neuroscientists are discovering more about how we learn to speak and remember, and there is huge excitement around how the technology could help identify and treat conditions including Parkinson’s and schizophrenia.

The tech’s mobility also offers applications in sports – it could provide instant scans for rugby players suffering a head injury on the field for example – or for those in the military with a traumatic brain injury.

While they hope for clinical approval in 2027, Gareth and Matt are not resting on their laurels. They are currently working on using the technology to map activity in the spinal cord, enabling investigation of neurodegenerative diseases such as multiple sclerosis that involve both the brain and the spinal cord.

“If I were to go back ten years and somebody could show me what we're doing now, I'd think it would look like science fiction. It really would,” says Matt. “The idea that we can scan people while they're standing up, walking around, dancing, yeah, it would have seemed like something from Star Trek."