Measurement of Magnetic Field Produced from the Human Body

This article describes the present status of research on biomagnetism, an interdisciplinary field of research involving biology, engineering, medicine, physics, psychology and other areas. Biomagnetic fields are caused either by electric currents in conducting body tissues such as the heart, the brain and muscles, or by magnetized material in lung contamination. These magnetic fields, although measurable, are so extremely weak that a superconducting quantum interference device (SQUID) magnetometer with ultra-high sensitivity is needed to detect magnetic flux generated outside the human body. This paper mainly focuses on the remarkable progress of research on biomagnetism involving magnetoencephalograms (MEGs) and magnetocardiograms (MCGs), and on the introduction of SQUID systems for measurement of biomagnetic fields.