the markets outside of the United States account for 42% of

　　the sales. These figures show the increasing emphasis that the

　　market may place on the miniaturization of medical

　　ultrasound.However， in order to make ultrasound technology more

　　portable and available at a lower cost a number of design

　　parameters need to be addressed.

　　First transducer design on stand-alone machines typically

　　consists of intricate transducer arrays created with highly

　　sensitive piezoceramics. These generally have a high cost

　　associated with them， and therefore are not directly suited for

　　low-cost applications.

　　Secondly the hardware implementation of the ultrasound

　　transmit and receive circuitry needs to be modified to become

　　more portable. Traditionally ultrasound technology usually

　　relies upon high voltages and currents to drive the transducer

　　as well as sensitive circuitry to receive the acoustic waveform.

　　Therefore to make a system portable， lower voltage and

　　current power sources must be used.

　　Finally the beamforming algorithm which is used to steer

　　and focus acoustic signals must be simplified for use on a

　　portable system. To meet these needs tradeoffs must be made

　　in order to create the machine small enough to satisfy its

　　reduce the cost and portability requirements， but also with

　　enough resolution to provide the medical practitioner an image

　　that can be clincally usefu