engleski

Applicability of the remote-field technique to contactless investigation of tissue electrical conductivity

In contactless measurement of tissue conductivity, a detector coil measures very weak secondary field produced by eddy currents within the tissue, in presence of a very strong primary field (direct coupling). A gradiometer is commonly used to reject the primary field and improve sensitivity to conductivity variations of the tissue. The same problem exists in nondestructive inspection of conductive tubes and it is solved by remote-field eddy-current (RFEC) technique. The technique essentially relies on spatial decoupling of a sensor from the exciter coil. The sensor placed at a certain distance senses the same level of secondary field, but much lower level of primary field. We have performed a finite-element analysis of magnetic field distribution of the exciter coil placed above the tissue with a small region of different electrical conductivity (blood vessel). Various locations of the blood vessel were modeled in order to examine a relation between sensitivity of detection and distance from the exciter coil. Our first findings confirm the applicability of the principle of spatial decoupling to investigation of tissue electrical conductivity.

bioimpedance; eddy current; remote field; biological tissue

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