Microwave-induced thermoacoustic tomography using multi-sector scanning

A study of microwave-induced thermoacoustic tomography of inhomogeneous tis sues using multisector 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-energ y density. The acoustic waves may propagate in all spatial directions. A fo cused ultrasonic transducer is employed to acquire temporal acoustic signal s from multiple directions. Each detected signal is converted into a one-di mensional (1D) image along the acoustic axis of the transducer. The cross-s ectional images of the tissue samples are calculated by combining all of th e 1 D images acquired in the same planes. (C) 2001 American Association of Physicists in Medicine.