Boundary conditions in photoacoustic tomography

Photoacoustic tomography has captured a significant amount of attention recently. Although several commercially available optical imaging modalities, including confocal microscopy, two-photon microscopy, and optical coherence tomography have been highly successful, none of these technologies can penetrate beyond ~1 mm into scattering biological tissues because all of them are based on ballistic and quasi-ballistic photons. Consequently, until now, there has been a void in high-resolution optical imaging beyond this depth limit. Photoacoustic tomography has filled this void by combining high ultrasonic resolution and high optical contrast in a single modality. Up until now, however, free-space ultrasound propagation has always been assumed in photoacoustic tomography. In this paper, boundary conditions that should be considered in certain imaging configurations are presented and their associated inverse solutions for image reconstruction are provided