On diffusive scaling in acousto-optic imaging

TL;DR

This paper analyzes how the stability of acousto-optic imaging reconstruction depends on the scattering properties of tissue, showing that increased photon scattering reduces stability and that laser concentration can mitigate this effect.

Contribution

It provides a quantitative stability analysis of AOI with respect to the Knudsen number, revealing the exponential dependence on photon scattering and proposing device concentration strategies.

Findings

Reconstruction stability decreases as Knudsen number approaches zero.

Laser beam concentration can counteract the loss of information due to scattering.

Numerical results verify the exponential error bound related to Knudsen number.

Abstract

Acousto-optic imaging (AOI) is a hybrid imaging process. By perturbing the to-be-reconstructed tissues with acoustic waves, one introduces the interaction between the acoustic and optical waves, leading to a more stable reconstruction of the optical properties. The mathematical model was described in [25], with the radiative transfer equation serving as the forward model for the optical transport. In this paper we investigate the stability of the reconstruction. In particular, we are interested in how the stability depends on the Knudsen number, Kn, a quantity that measures the intensity of the scattering effect of photon particles in a media. Our analysis shows that as Kn decreases to zero, photons scatter more frequently, and since information is lost, the reconstruction becomes harder. To counter this effect, devices need to be constructed so that laser beam is highly concentrated. We will give a quantitative error bound, and explicitly show that such concentration has an exponential dependence on Kn. Numerical evidence will be provided to verify the proof.