Scanning thermoacoustic tomograhy in biological tissue
Thermoacoustic tomography in the microwave region is explored to image biological tissue. When short-pulse electromagnetic energy is deposited into tissue, acoustic waves are generated due to thermoelastic expansion. The microwave-induced acoustic wave is detected with a focused ultrasonic detector. Each time-domain signal from the ultrasonic transducer represents a one-dimensional image along the acoustic axis. Scanning the system generates multi-dimensional images. The time-domain acoustic signal was simulated theoretically and measured experimentally, where the theoretical and experimental results were in good agreement. Two-dimensional tomographic images of biological tissue were obtained experimentally. Thermoacoustic tomography combines the advantage of microwaves in imaging contrast and the advantage of acoustic waves in imaging resolution.