The present invention relates to a system for real-time determination of a local strain of a lung during artificial ventilation. The system comprises a device for electrical impedance tomography (EIT), which device is configured to capture an electrical impedance distribution along at least one two-dimensional section through a human thorax, and further comprises a device for assigning the captured electrical impedance distribution, which device is configured to divide the captured electrical impedance distribution at different times during the artificial ventilation into a multiplicity of EIT pixels and to assign a specific value of the electrical impedance at a specific time to a specific EIT pixel.