A system for controlling the point spread function of an ultrasound signal transmitted into a patient. In accordance with one embodiment of the invention, only a selected number of the transducer elements transmit a transmit pulse. The elements which do not transmit the pulse are selected in accordance...http://www.google.com.au/patents/US6599245?utm_source=gb-gplus-sharePatent US6599245 - Ultrasound transmission method and system for simulating a transmit apodization
