An instrument for measuring the absolute output acoustic intensity, effective radiating area and beam non-uniformity ratio of medical ultrasound devices

A computer-controlled acoustic intensity measuring system (AIMS) for measuring the acoustic output of commercially manufactured diagnostic and therapeutic ultrasound devices is described. The hardware and software performance criteria and design tradeoffs resulting from experience with biomedical sound fields are also presented. The system allows three-orthogonal-axis (X, Y, and Z) position translation of up to 10 in by 10 in by 20 in with a 6.5-μm minimum step size, and is capable of waveform acquisition with a 50-MHz analog bandwidth and a maximum equivalent time sample rate of 5 GHz. The instrument can perform planar scans wherein the scan plane contains the acoustic beam axis, and two polar axes of position rotation can be added to the main positioner assembly at a later date