Image reconstruction in optoacoustic tomography accounting for frequency-dependent attenuation

Optoacoustic tomography (OAT) (also known as photoacoustic tomography or thermoacoustic tomography) is an emerging imaging modality that exploits the complementary strengths of optical and acoustical imaging to generate images whose contrast is due to optical absorption but whose resolution properties are determined by detected acoustic signals [1-16]. Briefly, one exposes a sample to pulses of electromagnetic radiation that cause small amounts of heating in the specimen. The heating engenders thermal expansion, which, in turn, gives rise to acoustic waves. The resulting acoustic pressure signal is generally measured by transducers arrayed around the object, usually on a planar, spherical, or cylindrical surface, and these data may be used to reconstruct images of the original electromagnetic absorption. Because the acoustic waves are generally less readily scattered in tissue than optical photons, the resulting images have higher resolution than compared to images that were obtained from measurements of the optical transmission.