Lorentz Field Electrical Impedance Tomography (LFEIT)

The method is a hybrid imaging modality based on electrical current induction using ultrasound and a static magnetic field. Time-varying voltages are measured using surface electrodes and/or coils placed near the body surface while the acoustic wave propagates along its path.  The feasibility of this technique was investigated using numerical studies and a novel coil configuration (xy coil pairs) was proposed. The performance of the imaging system was analyzed using the sensitivity matrix approach.  The characteristics of the imaging system were studied with the singular value decomposition (SVD) of the sensitivity matrix. Simulation studies based on the sensitivity matrix analysis reveal that perturbations with 5 mm×5 mm size can be detected up to a 3.5 cm depth.  A data acquisition system was developed based on magnetic field measurements. The static magnetic field was generated by permanent neodymium magnets. A 16-element linear phased array (LPA) transducer was utilized and contactless receiver sensors were developed using two similar disk multiple-layer coils.  Experimental studies were conducted with two different phantoms. A-scan and B-scan images of phantoms are obtained with the LPA transducer. Experimental studies reveal that 3 S m−1 conductive inhomogeneity can be detected with this data acquisition system.