The appliance includes an appliance body (12) as well as a system for producing microbubbles (20) and a system for producing an ultrasound signal beam (22) in a frequency range which activates at least some of the microbubbles. The appliance includes at least one of the following: (a) an array of ultrasound transducer elements (40) which produce a plurality of ultrasound signal beams (b) an amplitude modulation assembly (51) for modulating the amplitude of the ultrasound signal and (c) a frequency modulation system (61) for changing the frequency of the ultrasound signals over a selected range, to impact a range of microbubble sizes.
