Developments and Challenges on SQUID-based Biomagnetic Measurement Systems-Expansion of applications to spinal cord and peripheral nerve measurements

More than a decade has passed since multi-channel magnetoencepharography (MEG) systems based on superconducting quantum interference devices (SQUIDs) became commercially available. In collaboration with medical doctors, neuroscientists and engineers, MEG systems have been improved and progress continues to be made as one of the cutting-edge instruments useful for brain diagnosis and research. On the other hand, SQUID technology is also promising for new biomagnetic applications. MEG and other nerve measurement systems using SQUIDs are introduced and challenges from a technical point of view are described.