Solving time-independent inhomogeneous optoacoustic wave equation numerically with a modified Green's function approach.

Abstract

The purpose of the paper is twofold. First, a modified Green's function (MGF) approach is described for solving the time-independent inhomogeneous optoacoustic (OA) wave equation. The performance of this technique has been assessed with respect to the exact, traditional Born series and convergent Born series methods for an acoustically inhomogeneous spherical source. Second, we apply the same approach for calculating time domain signal from a blood vessel network consisting of an ensemble of acoustically homogeneous/inhomogeneous randomly positioned disks resembling cells. The predicted signals have been compared with those generated by the exact method and a freely available standard software. The OA spectra for a spherical source demonstrated excellent agreement with the exact results when sound-speed for the source was varied from -20% to 30% compared to that of the surrounding medium. The simulated OA signals also followed the same trend as that of the exclusively used software for the acoustically homogeneous blood vessel network. Future work will focus inclusion of a suitable phase factor within the MGF facilitating OA pulses building up at correct temporal locations for an acoustically inhomogeneous source.