AN ADAPTIVE CURRENT TOMOGRAPH USING VOLTAGE SOURCES

This paper describes the development of an adaptive electric current t omography system which contains a novel front-end analog architecture. Programmable voltage sources have been used to deliver currents into the study object and to avoid the difficulties of obtaining high quali ty current sources. Through inverting an admittance matrix, the system is capable of achieving a desired current drive pattern by applying a computed voltage pattern. The tomograph, operating at 9.6 kHz, compri ses 32 driving electrodes and 32 voltage measurement electrodes. The s tudy of system noise performance shows high SNR in the data acquisitio n which is enhanced by a digital demodulation scheme. In vitro reconst ruction images have been obtained with the data collected by the tomog raph.