Ultrasonic power balances--effect of a coupling window on the power measured from physiotherapy ultrasound units.
The output from physiotherapy ultrasound (US) probes is usually measured using a radiation force balance. Some balances are sealed and incorporate a membrane coupling window. The probes are highly resonant, and the output may be affected by changes in acoustic loading caused by the membrane. A model has been developed to examine this effect, and predicts that a polythene membrane 100-microm thick can change the output power by up to 17%.
Lunt
M J
MJ
Medical Physics Department, Dorset County Hospital, Dorchester, UK. michael.lunt@rbch-tr.swest.nhs.uk
Duck
F A
FA
D006801:Humans; D008567:Membranes, Artificial; D026741:Physical Therapy Modalities / Q000295:instrumentation*; D011095:Polyethylenes; D014464:Ultrasonic Therapy / Q000295:instrumentation*
D008567:Membranes, Artificial; D011095:Polyethylenes