A curved high intensity focused ultrasound (HIFU) transducer comprising a curved piezoelectric array having opposite convex and concave back surfaces, the front surface comprising an acoustic transmitting surface, and a plurality of electrodes located on the convex back surface for applying electrical transmit signals to the array, and a printed circuit board spaced apart from and in opposition to the back surface of the curved piezoelectric array which couples electrical signals to the electrodes of the array, the space between the printed circuit board and the curved piezoelectric array comprising an acoustic air backing passageway of the piezoelectric array for air-cooling the curved piezoelectric array and the printed circuit board.