Portable Electric Impedance Tomography System Development

In this work we present the design and early development of a portable Electrical Impedance Tomography (EIT) system consisting of a small stand-alone device capable of generate a stimulus and take measurements intended for EIT image reconstruction. The system follows the typical EIT architecture of stimulate the tissue with a known alternate current and then measure voltages in the boundary. All these stages have been implemented using only integrated circuits and a microcontroller. The current source generates a constant 1mApp sinusoidal current at 50 kHz and the ADC can measure differential voltages at 3 MS/s in multiple channels. The system has 16 current outputs/voltage inputs that connects with electrodes that would attach to the body. This design is intended for noninvasive breathing monitoring and ambulatory pulmonary function test.