Microwave-induced pressure waves in a model of muscle tissue

Microwave-induced mechanical stress waves were studied in simulated muscle tissue. Pulsed microwave energy at 5.655 GHz induced pressure waves that were recorded with a hydrophone transducer. Each pulse produced a peak power density greater than 1.5 kW/cm2. Microwave absorption measurements within the model showed energy deposition to be mostly confined to a region within 2 cm of the irradiated surface. The average specific absorption rate (SAR) at the surface of the sample was about 100 W/kg. The microwave-induced stress wave propogated at a velocity of 1,600 m/sec with peak pressures of approximately 300 pascals and was detectable after having traveled a total distance of 0.61 m on a path that included two reflections at model-container interfaces.