A method and system for secure ultrasound treatment of living tissues using an ultrasound probe comprising a reflective cavity in acoustic communication with living tissues, a transducer to emit an ultrasound wave in the reflective cavity and a transducer to acquire a backscattered signal in the reflective cavity. The method comprises the steps of a) emitting a first ultrasound wave in the reflective cavity that generates a backscattered ultrasound wave in the reflective cavity, b) acquiring a backscattered signal in the reflective cavity, c) determining whether an insonification can be safely performed by computing a similarity value between the backscattered signal and a predefined reference signal, and d) if an insonification can be safely performed, treating the living tissues with a second ultrasound wave emitted in the reflective cavity. The second ultrasound wave is focused a target point of the living tissues and generates a pressure point resulting in cavitation at this target point.