Thermoelastic Signatures of Tissue Phantom Absorption and Thermal Expansion

A microwave-induced thermoelastic pressure wave method for imaging of biological tissues has been investigated. Liquid-filled test tubes inside a water tank were used as phantom models. A pulsed 2.45 GHz microwave source and a hydrophone transducer were used to generate and to detect thermoelastic pressure waves. A pattern extraction algorithm was used to analyze the wave contours. Preliminary results show that the thermoelastic waveform is proportional to the size of the test tube and depends on the type of solution within the test tube. Two test objects can be detected with a spatial resolution better than 1 cm. These results suggest that a microwave-induced thermoelastic pressure wave system may provide valuable information for imaging tissue absorption and thermal expansion properties.