An inspection system for a metal-reinforced concrete structure is described. The system includes a radio frequency (RF) system configured to be movable with respect to a surface of the concrete structure while transmitting radio signals into the interior of the structure, and receiving reflected radio signals. The system also includes a processor configured to process the reflected radio signals, so as to obtain a focused image of the reinforcement in at least one selected region within the concrete structure. The image corresponds to the physical condition of the reinforcement. A method for determining the condition of a reinforced concrete structure is also described, utilizing the inspection system.