Abstract: The invention pertains to an angioplasty catheter for expanding and/or opening up morbidly constricted or obstructed blood vessels, comprising at least one rotor (3) that is rotatively mounted in a cylindrical housing (4) at the distal end of the catheter, is connected to a rotational actuator (2) and is guided in the axial and/or radial direction along a preset path of motion (5), where as a result of the guided motion, the turning rotor (3) mechanically generates endogenous sound waves, especially sound waves in the ultrasound range, and induces a corresponding motion of the housing (4).

Abstract: A method and device for measuring a volume flow of fluids in flow channels using ultrasound, wherein two ultrasonic transducers, each with a different transmitting frequency, are disposed in a flow channel in such a manner that emitted wave trains travel toward one another, with speed vectors of both wave trains having components that are in the flow direction and against the flow direction, and the superimposed signal is evaluated in terms of its position with respect to time.