Two years ago, researchers at the National Institute of Standards and Technology (NIST) in the U.S. developed a tiny magnetic sensor that could detect the human heartbeat without touching the subject's skin. Now, the same team has improved the sensitivity of the device tenfold, making it capable of measuring human brain activity and becoming almost as sensitive - but much cheaper and easier to operate - than the best magnetometers available today.
Magnetoencephalography (MEG) is a noninvasive procedure that measures the magnetic fields generated by the brain. This helps neuroscientists understand perceptual and cognitive processes, map cerebral activity to help identify tumors in preparation for surgery, or even create better brain-computer interfaces.
The pictured NIST device would be just one in an array of the 32 required to perform an MEG. The devices are kept in place by a helmet (Image: NIST)
Today, the gold standard in MEG technology are superconducting quantum interference devices (SQUIDs). But while extremely sensitive and effective, this technology isn't easy on the wallet. "Cooling to 4 degrees above absolute zero, which is required for current commercial SQUID-based systems, is very expensive and systems typically cost over US$1M," Dr. John Kitching told Gizmag.
This is where NIST's magnetometer comes in. By improving on their previous design, the researchers came up with a magnetic sensor the size of a sugar cube that is also cheaper to manufacture and can work at room temperature.
"Our sensors can be fabricated in parallel with techniques usually adopted for microelectronics," says Kitching. "Moreover, while SQUID-based imaging systems require a large magnetically-shielded room to operate, an imaging system based on our sensors could probably be operating in a much smaller (person-sized) shielded enclosure. These advantages will almost certainly make a potential imaging system less expensive to manufacture."