AN ELECTRICAL-IMPEDANCE TOMOGRAPHY MICROSCOPE

A circular array of 16 electrodes has been constructed for use as an e lectrical impedance tomography (EIT) microscope. The electrodes were m ade from 60 mu m diameter gold wires anchored to a printed circuit boa rd. The internal diameter of the array was 0.9 mm giving a theoretical spatial resolution of about 100 mu m. For EIT imaging, the array was connected to an imaging system operating at 82 kHz. Static images of c onducting and insulating filaments (copper wire and human hair) in sal ine solution were obtained as well as dynamic imaging sequences of gla ss microspheres migrating through the array. The interelectrode impeda nce was typically 5 k Omega and the transimpedances ranged from 14 to 210 Omega.