Electrical impedance tomography (EIT) is an imaging method that is able to estimate the electrical conductivity distribution of living tissue. This work presents a field programmable gate array (FPGA)-based multi-frequency EIT system for complex, time-resolved bioimpedance measurements. The system has the capability to work with measurement setups with up to 16 current electrodes and 16 voltage electrodes. The excitation current has a range of about 10 μA to 5 mA, whereas the sinusoidal signal used for excitation can have a frequency of up to 500 kHz. Additionally, the usage of a chirp or rectangular signal excitation is possible. Furthermore, the described system has a sample rate of up to 3480 impedance spectra per second (ISPS). The performance of the EIT system is demonstrated with a resistor-based phantom and tank phantoms. Additionally, first measurements taken from the human thorax during a breathing cycle are presented.
@article{arxiv.2008.05716,
title = {A FPGA-Based Broadband EIT System for Complex Bioimpedance Measurements -- Design and Performance Estimation},
author = {Roman Kusche and Ankit Malhotra and Martin Ryschka and Gunther Ardelt and Paula Klimach and Steffen Kaufmann},
journal= {arXiv preprint arXiv:2008.05716},
year = {2020}
}