Patent ID: 7941210

Claim:
An electroimpedance tomography comprising: a plurality of electrodes for placement on a body of a patient; a control and evaluating unit; a selector switch; a measuring amplifier; an AD converter; a symmetrical AC power source used to reduce common-mode signals, said electrodes being connected to said control and evaluating unit via said selector switch, wherein said control and evaluating unit cooperates with said selector switch such that two of said electrodes as an electrode pair are each supplied with an alternating current from said symmetrical AC power source and the detected analog voltage signals of the other said electrodes are processed in order to reconstruct therefrom the impedance distribution of the body in the plane of the electrodes; and a common-mode signal measuring electrode, said control and evaluating unit detuning the common-mode signal of the alternating current applied on the body with respect to an electrical ground by means of said common-mode signal measuring electrode and, based on this, the symmetry of said symmetrical AC power source such that the common-mode signal on the body is minimized, and the corresponding detuning parameters are stored for each electrode pair.