Some Experimental Results on the Thermoacoustic Imaging of Tissue Equivalent Phantom Materials

Thermoacoustic waves were induced in vivo and in soft tissue phantoms consisting of layers of muscle tissue phantom gel and vegetable oil by 0.4 microsecond duration electric current pulses. The acoustic signals were detected by a 0.5 MHz transducer after digital signal averaging of typically 10 to 103 waveforms. The observed signals had the amplitude and time delay characteristics expected for thermoacoustic emission. The results support the feasibility of thermoacoustic imaging of soft-tissue by a transducer-amplifier-averaging system optimized for this application which might give information complementary to conventional ultrasonic and x-ray systems.