System and method for electrical impedance tomography of an object, and an impedance measurement unit

An impedance measurement unit configured to be used in a system for electrical impedance tomography, wherein the impedance measurement unit comprises:

• a first and a second connection interface for connecting the impedance measurement unit to a first and a second electrode;
• a current generator for generating a stimulation current for output through the first and the second connection interface for providing a current between the first and the second electrode;
• an amplifier configured to receive input from the first and the second connection interface of a measurement voltage across the first and the second electrode, said amplifier being configured to amplify the measurement voltage;
• and a control input interface for receiving a control signal for repeatedly shifting a mode of the impedance measurement unit between a stimulation mode, wherein the current generator is configured to generate the stimulation current, a measurement mode, wherein the amplifier is configured to receive the measurement voltage, and a calibration mode, wherein the current generator and the amplifier of the impedance measurement unit is calibrated.

A method for electrical impedance tomography of an object by a system comprising a plurality of electrodes and a plurality of impedance measurement units wherein each impedance measurement unit is associated with two electrodes of the plurality of electrodes, said method comprising for performing an impedance measurement:

• setting one impedance measurement unit into a stimulation mode for providing a stimulation current into the object between the electrodes associated with the one impedance measurement unit;
• setting impedance measurement units on opposite sides of and neighboring to the one impedance measurement unit being set in the stimulation mode into a calibration mode for calibration of the impedance measurement unit;
• and
• setting impedance measurement units not being in the stimulation mode or the calibration mode into a measurement mode for measuring a voltage between the electrodes associated with the impedance measurement unit.