Temporal backward projection of optoacoustic pressure transients usingFourier transform methods

Abstract

In medical imaging different techniques have been developed to gaininformation from inside a tissue. Optoacoustics is a method to generatetomography pictures of tissue using Q-switched laser pulses. Due to thermaland pressure confinement, a short light pulse generates a pressure distributioninside tissue, which mirrors absorbing structures and can be measured outsidethe tissue. Using a temporal back-projection method, the pressure distributionmeasured on the tissue surface allows us to gain a tomography picture of theabsorbing structures inside tissue. This study presents a novel computationalalgorithm, which, at least in principle, yields an exact reconstruction of theabsorbing structures in three-dimensional space inside the tissue. Thereconstruction is based on 2D pressure distributions captured outside atdifferent delay times. The algorithm is tested in a simulation andback-projection of pressure transients of a small absorber and a single pointsource.