HEART MONITORING WITH HIGH-T-C DC SQUID

We develop a one-channel high-T-c d.c. SQUID heart monitoring system f or non-invasive measurement in non-shielded environment. For this purp ose we used step-edge as well as bicrystal Josephson junctions for the preparation of planar direct coupled thin film gradiometers and magne tometers. These sensors have been tested for suitability and both kind s of sensor (magnetometer and gradiometer) have been used for measurin g the human heart activity (MCG) in a shielded environment. Because th e system will be used for clinical instrumentation without any shieldi ng, the influence of compensation of the earth's magnetic field in non -shielded environment with Helmholtz coils has been investigated. We a lso developed software for a real time data display, storage and furth er processing (e.g. digital filtering). (C) 1997 Published by Elsevier Science Ltd.