Application of the Superconducting Quantum Interference Device (SQUID) Magnetometer in Biomedical Research

About the Lecture

A magnetometer with a superconducting quantum interference device (SQUID) can measure the very small magnetic fields produced by the brain. The procedure is called magnetoencephalography (MEG). Thus MEG is a functional test and, in that respect, is equivalent to electroencephalography (EEG). The superconducting state is obtained by liquid helium. The largest magnetometer currently available commercially is a 37-sensor system, which covers only a portion of the brain at one measurement. It will soon be replaced with 64- and 122-channel Systems that can measure the whole head at once. The primary application of this technology to biomedical research is the noninvasive localization of the sources of current generated in the brain with epileptic seizures, migraine headaches, and various cerebral evoked responses. Its area of application is expanding, but as yet there is no established routine use of MEG, and the installation of an MEG system is prohibitively expensive for many institutions. My presentation will focus on MEG in epilepsy research. Many investigators believe that the combined use of EEG and MEG, taking advantage of each method, may be more powerful in characterizing the current sources than either method alone.