MEASUREMENTS IN BIOLOGICAL MEDIA
C. Boulay, Robert Guardo, Michel J. Bertrand · 1988
INSTRUMENTATION CONCEPT Biomedical applications of electrical impedance measurement include: real-time monitoring of cardiac output, ventricular work (P-V diagram) and respiration as well as imaging of the tissue conductivity distribution in the human body. To meet data acquisition requi rements for these different research fields, a versatile instrumentation system (HEMOS 3) has been developed for multi-channel impedance measure ments. HEMOS 3 is a micro-computer based system providing current stimulation, differential voltage measurement, quadrature demodulation, aid conversion and data processing. For impedance imaging purposes, the system also includes a multiplexer for current stimulating electrodes which allows the definition of a programmable sequence of projections. The system is fully controllable by a personal computer via an opto isolated port. A system description and preliminary results for an impedance imaging experiment are presented in this paper.