k -space propagation models for acoustically heterogeneous media: Application to biomedical photoacoustics

Abstract

Biomedical applications of photoacoustics, in particular photoacoustic tomography, require efficient models of photoacoustic propagation that can incorporate realistic properties of soft tissue, such as acoustic inhomogeneities both for purposes of simulation and for use in model-based image reconstruction methods. k-space methods are well suited to modeling high-frequency acoustics applications as they require fewer mesh points per wavelength than conventional finite element and finite difference models, and larger time steps can be taken without a loss of stability or accuracy. They are also straightforward to encode numerically, making them appealing as a general tool. The rationale behind k-space methods and the k-space approach to the numerical modeling of photoacoustic waves in fluids are covered in this paper. Three existing k-space models are applied to photoacoustics and demonstrated with examples: an exact model for homogeneous media, a second-order model that can take into account heterogeneous media, and a first-order model that can incorporate absorbing boundary conditions.

Aberration correction for transcranial photoacoustic tomography of primates employing adjunct image data

“…The development of image reconstruction methods for addressing this problem is an active area of research. [26][27][28] In this work, we employed a k-space pseudospectral timereversal image reconstruction algorithm that has been developed by Treeby and Cox. 29 The reconstruction algorithm approximates Eqs.…”

“…The re-orientated SOS and density maps were employed with the k-space time-reversal PAT image reconstruction algorithm developed by Cox et al 28 The numerical implementation of this algorithm provided in the Matlab k-Wave Toolbox 29 was employed. The measured PA signals were pre-processed by a curvelet denoising technique prior to application of the image reconstruction algorithm.…”

A Study of the Virtual Microphone Algorithm for ANC System Working in Audio Interference Environment

“…This simulation method is based on a series of coupled discrete first-order partial differential equations including moment conservation, mass conservation, and pressure-density relation equations using the k-space pseudospectral method [11]. The k-space propagation models were experimentally validated by B. T. Cox et al [12].…”

Artifact Trapping During Time Reversal Photoacoustic Imaging for Acoustically Heterogeneous Media

“…1(h) will be discussed in Section IV-B below. In this example, and those given below, a -space propagation model based on (1) was used to simulate the measured data, and a similar model, but with and set to constant values, was used for the image reconstruction [14], [15].…”

“…In 2-D, this will never (quite) be the case, but in practice it is only necessary to record until the pressure has dropped to a sufficiently low nonzero value. These forward simulations were performed using the k-space method described in [14] and [15], on a 256 256 pixel square grid, with a sound speed of 1500 m/s, and time steps of 7.8 ns. Random noise was added at 5% of the maximum value of the "measured" data, and the measurements were interpolated onto a 304 304 pixel grid for use in the image reconstruction.…”