Abstract: The method of the disclosure comprises the stages of injecting an alternating AC signal into at least one electrode positioned on the skin of the patient in a region of interest, measuring the signal induced into at least one electrode, extracting at least an envelope of the signal measured and determining the difference between the envelope and a reference signal. The envelope may be extracted by demodulating the signal measured, and this demodulation may be carried out by way of an associated rectifier diode, in a preferred embodiment, and an RC filter. The reference signal may be an envelope corresponding to the demodulated signal of another electrode, the injected signal, ground or a fixed voltage value.

Abstract: There are disclosed a method and an equipment for monitoring current drained by a grounding electrode in an electric impedance tomography system. The grounding electrode and a set of electrodes may be simultaneously applied to a patient in an electric impedance tomography apparatus. The equipment may be configured to convert current into a voltage signal and amplify, demodulate, and filter the voltage signal in order to recover its almost continuous component. The equipment may further be configured to compare the value of the continuous component with limit/threshold values proportional to an intensity of an excitation current applied to the set of electrodes. In addition to detecting the disconnection of the grounding electrode, the comparison may also detect the disconnection of one or more tomography electrodes, as well as unbalance in the currents injected through the electrodes and the contact of the patient with voltage sources or conductive bodies.

Abstract: There are disclosed a method and an equipment for monitoring the current drained by the grounding electrode in an electric impedance tomography system, the said grounding electrode (16) and the set of electrodes (11) being simultaneously applied to a patient (12) in an electric impedance tomography apparatus (14, 15), comprising the conversion of the said current into a voltage signal (41) and the amplification, demodulation and filtering thereof, in order to recover its almost continuous component (44, 45, 46, 47, 48) and the comparison of the value of the latter with limit/threshold values (v1, v3, v4, v6) proportional to the intensity of the excitation current applied to the said set of electrodes.

Abstract: There is described an electrical impedance tomography equipment, intended for providing images representing the inside of a portion of the body of a patient by means of electrical impedance measurements taken between electrodes positioned on the skin, comprising a plurality of acquisition units (15, 27) provided with circuits for processing low level analog signals picked up by the cables (13, 29) that interconnect the said equipment with the electrodes (14) applied to the patient, the said acquisition units being substantially symmetrically arranged to provide as a result a substantially equal irradiation of the heat generated in these units, easing the calibration of the analog channels and common mode rejection. The equipment further comprises at least one plane constituted by a printed circuit board whereto the said units are electrically connected, the said plane comprising complementary elements and devices, such as the electrical connection terminals for the said cables.