Abstract: System and methods for performing a therapeutic procedure using focused ultrasound include providing a piezoelectric transducer including a plurality of transducer elements, such as a concave concentric ring array or a liner array of transducer elements. Drive circuitry is coupled to the transducer for providing drive signals to the transducer elements at one of a plurality of discrete RF frequencies. A controller is coupled to the drive circuitry for periodically changing a frequency of the drive signals to one of the plurality of discrete frequencies, while controlling a phase component of the drive signals to maintain the focus of the transducer at a primary focal zone during a single sonication.