Quantitative photoacoustic tomography using illuminations from a single direction

Abstract

Abstract. Quantitative photoacoustic tomography is an emerging imaging technique aimed at estimating optical parameters inside tissues from photoacoustic images, which are formed by combining optical information and ultrasonic propagation. This optical parameter estimation problem is ill-posed and needs to be approached within the framework of inverse problems. It has been shown that, in general, estimating the spatial distribution of more than one optical parameter is a nonunique problem unless more than one illumination pattern is used. Generally, this is overcome by illuminating the target from various directions. However, in some cases, for example when thick samples are investigated, illuminating the target from different directions may not be possible. In this work, the use of spatially modulated illumination patterns at one side of the target is investigated with simulations. The results show that the spatially modulated illumination patterns from a single direction could be used to provide multiple illuminations for quantitative photoacoustic tomography. Furthermore, the results show that the approach can be used to distinguish absorption and scattering inclusions located near the surface of the target. However, when compared to a full multidirection illumination setup, the approach cannot be used to image as deep inside tissues. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Direct Estimation of Optical Parameters From Photoacoustic Time Series in Quantitative Photoacoustic Tomography

“…In this work, the prior model for the unknown parameters µ a and µ s was chosen to be based on the Ornstein-Uhlenbeck process [45], [63], [83]. The prior is a Gaussian distribution with the covariance matrix defined as being proportional to matrix Ξ which has its elements defined as…”

“…Commonly, a model based inversion approach is used to solve the inverse problem in QPAT. Both, the radiative transfer equation (RTE) based optical propagation model [39]- [45] and its diffusion approximation (DA) [46]- [55] have been used. In addition to using photoacoustic images as the input data in the quantitation step, combined data formed by the photoacoustic images and diffuse optical tomography (DOT) measurement data have been investigated [42], [56], [57].…”

Quantitative photoacoustic tomography augmented with surface light measurements

“…In QPAT, the most common approach has been to use the diffusion approximation (DA) as the light transport model, although the radiative transfer equation (RTE) has also been utilised [15,21,25,38,47,48]. Recently, utilising Monte Carlo simulation methods have also been considered [35,49].…”

Effects of the approximations of light propagation on quantitative photoacoustic tomography using two-dimensional photon diffusion equation and linearization

“…The propagation of the light is described by the following RTE [4,23,24], s Á r/ðr; sÞ þ l a ðrÞ þ l s ðrÞ f g /ðr; sÞ…”

“…Saratoon et al used RTE [23]. Pulkkinen and coworkers investigated the image reconstruction based on RTE with illumination from a single direction [24].…”