A Survey of Output Characteristics of Some New Therapeutic Ultrasound Instruments Manufactured in Australia

Seven newly purchased therapeutic ultrasound transducers were tested using a radiation pressure balance and steel baffles in compliance with Australian Standard Specification T40-1969. Total acoustic output at maximum meter settings, and effective transducer radiating areas were measured. Only one transducer demonstrated the output values nominated by the manufacturer. Two had an appropriate relationship between effective area and total output, though these values were not those stated by the manufacturer. The remaining four had effective radiating areas below the Australian Standards Association tolerance. Three of these had an otherwise acceptable power output and one had a very low output. These data substantiate the need for adequate testing facilities to be available for physiotherapists using ultrasound clinically