Ultrasound wattmeter

Abstract

An ultrasound wattmeter for measuring the magnitude of energy radiated by a therapeutic ultrasound applicator includes a sealed, oil-filled housing within which a float assembly is suspended. The float assembly includes an ultrasound reflective float as well as a coil and a vane supported by the float. The float assembly assumes a null position in the absence of ultrasonic radiation. A window in the housing permits the application of ultrasonic energy from the applicator to the float for urging the float assembly in one direction from the null position. A magnet mounted on the housing adjacent the coil urges the float assembly in the opposite direction in response to energization of the coil. A light source and a light responsive device are located adjacent the vane for providing a position signal corresponding to the position of the float assembly. An energization circuit energizes the coil in response to variations in the position signal in order to maintain the float assembly in its null position, and a meter coupled to the energization circuit provides an indication of the coil energization level which also is an indication of the ultrasonic energy radiated by the applicator.