Temporal backward projection of optoacoustic pressure transients using Fourier transform methods

In medical imaging different techniques have been developed to gain informa tion from inside a tissue. Optoacoustics is a method to generate tomography pictures of tissue using Q-switched laser pulses. Due to thermal and press ure confinement, a short light pulse generates a pressure distribution insi de tissue, which mirrors absorbing structures and can be measured outside t he tissue. Using a temporal back-projection method, the pressure distributi on measured on the tissue surface allows us to gain a tomography picture of the absorbing structures inside tissue. This study presents a novel comput ational algorithm, which, at least in principle, yields an exact reconstruc tion of the absorbing structures in three-dimensional space inside the tiss ue. The reconstruction is based on 2D pressure distributions captured outsi de at different delay times. The algorithm is tested in a simulation and ba ck-projection of pressure transients of a small absorber and a single point source.