A device for treatment of a tissue (8) of a living being, including a transducer (4) for emitting a beam of ultrasound waves mounted on a movable treatment head (1), an ultrasonic imaging device (2, 3), optionally an inflatable balloon (5) surrounding the treatment head (1) and containing a coupling fluid, and a control unit for controlling movement of the treatment head (1) and operation of the transducer (4) and the imaging device (2, 3). In order to avoid displacement of tissues (7, 8) during displacement of the treatment head (1) and increase imaging quality, the treatment head (1) is adjustable to at least two of a treatment position (T), a monitoring position (M) and a travel position (S).