The disclosed apparatus of the invention operates to generate and direct ultrasound over predetermined regions of a body, such as a programmed sequence of target points. A plurality of side-by-side tapered piezoelectric transducer elements are provided. Means are provided for energizing the transducer...http://www.google.se/patents/US4549533?utm_source=gb-gplus-sharePatent US4549533 - Apparatus and method for generating and directing ultrasound
