Implementation of a low cost prototype for electrical impedance tomography based on the integrated circuit for body composition measurement AFE4300

Electrical impedance tomography (EIT) is a technique of image reconstruction of the electrical conductivity distribution in a tissue or region under observation. An electrical system for EIT comprises complex hardware and software modules, which are designed for a specific application which requires that the system to be able to detect conductivity variations within the study object. The Front-End for body composition measurement, AFE4300 from Texas Instruments allows a minimal implementation of an electrical impedance tomography system. It is the main device in the development of the EIT system presented in this paper, this device injects the current signal and measures the tensions generated on the study region boundary by 8 electrodes, the image reconstruction software was developed on the National Instruments platform Labview. The system includes a microcontroller PIC16F886 to configure the 8 channels for the definition of the patterns of injection and measurement of signals, also defines the current signal frequency and the bluetooth communication with the computer for the image reconstruction. The developed system was validated by a planar resistive phantom (CardiffEIT phantom), obtaining a stable voltage measurement every 50 ms per pair of electrodes, and a signal to noise ratio (SNR) maximum of 71.8 dB, for a current signal of 50 kHz. Additionally, tests were carried out in a saline tank with a concentration of 4 g/L, the developed system can simultaneously estimate the presence of conductive and non-conductive disturbances into the tank. CopyrightPeer ReviewedPostprint (published version