Design of an ECG gated data collection system for electrical impedance tomography

Abstract

This thesis is concerned with the design of an `ECG-gatedelectronic hardware for data collection in electrical impedancetomography. The actual design uses the current injection-voltagemeasurement technique with 16 electrodes. The electrodes areaddressed through four analog multiplexers.A 50kHz sinusoidal current is injected between adjacentelectrode pairs and peripheral potential differences are recorded byserially stepping around adjacent electrode pairs. Data collectionsynchronization is achieved using R-wave detection. After each Rwaveof the patient's EeG, 13 voltage measurements are done for aspecific current-drive position, and total data collection is achieved in16 cardiac cycles.To comply with electrical safety requirements, both voltagemeasurement and current injection circuits are isolated from eachother as well as from earth ground.