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Focused Impedance Measurement (FIM) system uses six electrodes to localize a zone of interest. The present work represents a modified FIM technique using four electrodes placed at the corners of a square matrix. In this technique firstly current is driven through an adjacent electrode pair while the potential is measured across the opposite pair from which an impedance value is obtained. Then a similar measurement is made at 90 degree to the above by changing the electrode pairs appropriately. The sum of these two impedance values has a dominant contribution from the central region within the square matrix, giving the desired focusing. Measurements made on a 2D phantom have verified the desired performance successfully in the present work. Results presented through sensitivity maps and sensitivity curves using insulating, conducting objects and an object of organic conductivity (potato) demonstrate the focusing effect clearly. Because of 3D sensitivity it could give physiological information on large organs like stomach, lungs, etc. using surface electrodes in the frontal and transverse plane.

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Affiliation: Lecturer, Department of Physics, Bangladesh University of Engineering and Technology (BUET), Dhaka-1000, Bangladesh Research Interest: Bio-Medical Physics and Applications, Electrical Bio-impedance Measurement.

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