Magnetic Induction Tomography: A Measuring System for Biological Tissues

Abstract

A single-channel magnetic induction system operating at 10 MHz has been constructed. The system consists of an excitation coil and a sensing coil, between which different objects can be scanned. The eddy currents induced in the object cause perturbations in the sensed magnetic field, which are measured with a phase-sensitive detector with backing off of the signal to improve sensitivity. Scans were obtained for saline solutions with conductivities ranging from 0.001 to 6 Sm-1, encompassing the range for biological tissues. The imaginary part of the perturbation in the sensed magnetic field was found to be proportional to saline conductivity, consistent with theoretical prediction, and had a constant of proportionality of -1.2% per Sm-1. A filtered back-projection algorithm was used to generate tomographic images from the scans.

Biological impedance cross evaluation and imaging from composite measurements of magnetic and electrical methods

“…The sinusoidal current injected in the excitation coil is 20 mA at 10 MHz [11]. The source of the sinusoidal signal is the highly stable and temperature-compensated crystal oscillator.…”

Development of magnetic induction spectroscopy system in biomedical application to detect jaundice

“…Then, magnetic field that produced by transmitter coil pass through object that's under study, thus induce eddy current and flow through receiver coil. Therefore, receiver coil turn to secondary magnetic field [10], [11]. …”

Reduction of low-frequency noise in magnetic induction tomography systems

“…20 MHz, [2], 10 MHz [1,4]. However, measurements in the β-dispersion range below 1 MHz are desirable because many pathological processes are reflected there [5].…”

“…Magnetic induction tomography (MIT) [1], [2], [3] is a contact-less imaging modality which maps the electrical conductivity within a 3-D body. MIT requires an alternating magnetic excitation field to be coupled from an array of transmit coils (TXC) to the object.…”