SPICE and MATLAB simulation and evaluation of Electrical Impedance Tomography readout chain using phantom equivalents

Abstract

Electrical Impedance Tomography (EIT) is an imaging technique which has gained popularity in both the medical and industrial process fields. A small amplitude sinusoidal current is utilized, while potential measurements are collected from an electrode array, attached to an object’s surface and used for generating a map of its relative conductivity distribution. In this study, an extensive simulation methodology is presented. It uses cylindrical phantom multiport equivalent passive circuits and focuses on analog and digital readout parameters such as the measuring pattern, the ADC sampling rates, the total periods utilized for each measurement as well as the thermal, flicker and quantization noise effects. The EIT analog circuitry, merged with the subject multiport equivalent is simulated in SPICE, while the digital part is simulated in MATLAB. The presented simulation procedure can assist on specifying important EIT design and measuring parameters, such as the required ADC characteristics, minimum noise and number of periods for averaging. It can also be used in the evaluation of image reconstruction approaches and noise robustness testing.