Diamond sensor for smaller portable MEG scanners


Researchers at RMIT University in Australia have developed a diamond sensor that can measure magnetic fields up to 10 times more sensitive than current sensors. This breakthrough could lead to a new generation of magnetoencephalography (MEG) scanners that are small and portable and can operate at room temperature. The researchers envision the new scanners could even function as a helmet that a patient could place on their head, making it useful for detecting concussions at the point of care or for routine monitoring of neurodegenerative diseases. The new sensor does not lose any of the light generated by diamond flaws in response to the magnetic field, which means it is very sensitive.

MEG scanners detect the magnetic activity of neurons in the brain and the data is visualized as brain waves. The technique is useful for identifying brain disorders and tracking brain activity. The scanners work with diamond sensors, inside which quantum defects emit light in response to the measured magnetic field. However, current sensors cannot detect all the light and most of it is lost, resulting in signal loss. These researchers introduced a laser into the mix, which helped bind this elusive light, resulting in a significant increase in sensitivity.

“Our breakthrough was to make a laser out of the defects,” said Andrew Greentree, one of the main developers of the new technology. “By collecting all the light – instead of just a small amount – we can detect the magnetic field 10 times more accurately with our sensor compared to current best practice.”

The new sensor could lead to a change in MEG scanners. Current devices are bulky and expensive, and require very cold temperatures to operate, relying on expensive liquid helium systems. “Current MEG machines are huge devices, with dedicated fixtures, and they also require magnetic shielding around them,” Greentree said. “We really want to have something that we can put on a patient’s head and we want them to be able to move around – and there wouldn’t be a need for expensive liquid helium to run such a device.”

The new scanners, which the researchers hope to develop in the next few years, would be much smaller and could operate at room temperature. Surprisingly, they could function as a helmet that a patient can wear while moving around. The technology could be useful in assessing and monitoring various conditions.

“With Alzheimer’s disease, you want to be able to monitor the progression of the disease and know the effect of any treatment,” Greentree said. “It’s the same with a concussion, you want to be able to measure what’s happening in the brain after each hit. With this MEG technology that we are considering, you may be able to detect early dementia. With epilepsy, you could find out where it’s happening, and that would help you better target interventions.

Study in the journal Scientists progress: Magnetic field-dependent stimulated emission from nitrogen vacancy centers in diamond

Going through: RMIT University


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