Heating caused by selected pulsed Doppler and physiotherapy ultrasound beams measured using thermal test objects

Objective: To assess the heating caused by selected pulsed Doppler and physiotherapy ultrasound beams by measurements made using thermal test objects. Method: Thermal test objects were used to measure temperature rises in selected ultrasound fields. These were compared with theoretical predictions based on standard exposure measurements. A separate thermocouple was used to measure heating at the transducer surface. Results: Temperature rises of up to 6 °C were measured for Doppler fields using a thermal test object. The attenuation-corrected temperature rises that were measured generally agreed with calculated Thermal Indices. Temperature rises of up to 2 °C were observed for physiotherapy ultrasound fields in pulsed operation. Conclusion: Significant overlap between the measured temperature rises of selected pulsed Doppler and physiotherapy ultrasound fields was observed.