7-channel on-scalp MEG-system using high-Tc SQUID magnetometers

A seven-channel magnetoencephalography (MEG) system based on high-Tc Superconducting Quantum Interference Devices (SQUIDs) has been built, characterized, benchmarked against a commercial state-of-the-art full-head MEG system, and clinically evaluated. Compared to conventional MEG using low-Tc SQUIDs, we can decrease the sensor-to-head distance from about 20 mm to about 1 mm. This increases the signal significantly and makes it possible to increase the spatial resolution. To validate the technology, we have done comparative studies on the visual and somatosensory cortex and done a first clinical study on an epileptic patient. Superficially, the high-Tc MEG system performs essentially similarly to the commercial low-Tc based system, but the signals are stronger and of more complex nature. Keywords—MEG; high-Tc; SQUID; styling; insert (key words)