Beagleboard Ultrasonic Transducer

Hello beagleboarders:

I want to know if any of you have some experience working with ultrasonic transducers for medical applications connected to the beagleboard (I think that some kind of USB ultrasonic transducers will be the better choice for usb-oriented beagleboard) and how was it. I want to know also if you have information of some company that is selling this kind of ultrasonic transducers (linear array).

Thank you all of you !