Ultrasound-guided photoacoustic image reconstruction

Photoacoustic signals originating from weak sources can be hard to discriminate from higher intensity signals resulting from the photoacoustic background. In order to reveal these weaker signals we propose a method where the expected background signal is subtracted from the actual signals. In this method an ultrasound image provides the geometry for the pressure distribution used in a photoacoustic wave field simulation. The simulated photoacoustic signals are subtracted from the actual recordings and the residual is used for image reconstruction. This method was successfully validated experimentally with a vessel phantom containing three optical absorption irregularities within the vessel wall.