Photoacoustic Tomography: Deep Tissue Imaging by Ultrasonically Beating Optical Diffusion

Abstract

Photoacoustic tomography has been developed for in vivo functional, metabolic, molecular, and histologic imaging by physically combining optical and ultrasonic waves. Broad applications include early-cancer detection and brain imaging. High-resolution optical imaging---such as confocal microscopy, two-photon microscopy, and optical coherence tomography---is limited to superficial imaging within the optical diffusion limit ({\textasciitilde}1 mm in the skin) of the surface of scattering tissue. By synergistically combining light and sound, photoacoustic tomography provides deep penetration at high ultrasonic resolution and high optical contrast.