Simulations of optoacoustic wave propagation in light-absorbing media using the finite difference time-domain method

Optoacoustic (OA) imaging is an emerging technology that combines the high contrast of tissue optical properties and the high spatial resolution of ultrasound. In order to take full advantage of the imaging scheme, a better understanding of the OA wave propagation in light-absorbing media is necessary. In this study we propose a new numerical approach based on the finite difference time-domain (FDTD) method to solve the general OA equations. We adopted a MacCormack-type splitting scheme for modeling OA wave propagation in a light-absorbing medium with heterogeneous acoustic properties. The FDTD code was validated both numerically and experimentally. Characteristics of simulated OA waveforms and OA images are discussed, with emphasis laid upon the effects caused by acoustic heterogeneities in practical imaging conditions.