Electrical impedance endotomography.

In electrical impedance endotomography (EIE), the impedance measuring electrodes are placed at the centre of the region of interest instead of encircling it, as in usual electrical impedance tomography. EIE has been developed for prostate imaging. The developed mathematical model enables the derivation of analytical equations for electric potential, electric field and sensitivity. This paper focuses on the selection of an optimal current injection method capable of sensing distant points. Experimental measurements were carried out in vitro using an enlarged size, 50 mm diameter, 16-electrode mock-up probe placed in tap water. The collected data enabled the production of images of a circular insulating target, 10 mm in diameter located 100 mm from the axis of the probe. Future work includes extension of sensitivity range, improvement of image reconstruction, design of a multiple frequency hardware system and construction of a real-size, biocompatible impedance probe.