Microwave-induced acoustic imaging of biological tissues

The tomographic imaging of biological tissues using microwave induced acoustic signal is presented. The acoustic signal was proportional to the intensity of the incident microwave and was related to the absorption property of microwave in the medium. Pulsed microwave energy caused thermoelastic expansion that radiated acoustic waves. A focused ultrasonic transducer detected the time resolved acoustic signals. Each acoustic signal was converted into a 1D image. A linear scanning of the ultrasonic transducer yielded multiple 1D images, which formed a 2D image. The imaging contrast is based on the difference in the dielectric constants among biological tissues.