Microwave-induced thermoacoustic tomography using multi-sector scanning.

A study of microwave-induced thermoacoustic tomography of inhomogeneous tissues using multi-sector scanning is presented. A short-pulsed microwave beam is used to irradiate the tissue samples. The microwave absorption excites time-resolved acoustic waves by thermoelastic expansion. The amplitudes of the acoustic waves are strongly related to locally absorbed microwave-energy density. The acoustic waves may propagate in all spatial directions. A focused ultrasonic transducer is employed to acquire temporal acoustic signals from multiple directions. Each detected signal is converted into a one-dimensional (1D) image along the acoustic axis of the transducer. The cross-sectional images of the tissue samples are calculated by combining all of the 1D images acquired in the same planes.