We analyse the effect on scattered photons of anomalous optical inclusions in a turbid slab with otherwise uniform properties. Our motivation for doing so is that inclusions affect scattering contrast used to quantify optical properties found from transmitted light intensity measured in transillumination experiments. The analysis is based on a lattice random walk formalism which takes into account effects of both positive and negative deviations of the scattering coefficient from that of the bulk. Our simulations indicate the existence of a qualitative difference between the effects of these two types of perturbations. In the case of positive perturbations the time delay is found to be proportional to the square of the size of the inclusion while for negative perturbations the time delay is a linear function of its volume.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1088/0031-9155/50/23/011 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Using spectral derivatives to remove the influence of hair on optical images of the static absorbing properties of tissue-like turbid media.
Neurophotonics
April 2024
University College London, Department of Medical Physics & Biomedical Engineering, London, United Kingdom.
Significance: Although measurements of near-infrared light diffusely reflected from the head and other biological tissues are commonly used to generate images revealing changes in the concentrations of oxy- and deoxy-hemoglobin, static imaging of absolute concentrations has been inhibited by the unknown and variable coupling between the optical probe and the skin, to which hair is often a significant contributor. Measurements of spectral derivatives provide a means of overcoming this shortcoming.
Aim: The aim is to demonstrate experimentally that measurements of the derivative of the attenuation of the detected signal with respect to wavelength can be used to achieve images that are immune to the spatial variation of hair on the surface.
Camera-based CW Diffuse Optical Tomography for obtaining 3D absorption maps by means of digital tomosynthesis.
Biomed Phys Eng Express
November 2020
Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany.
We present a novel method for obtaining a 3D absorption map of a tissue-like turbid slab in the near-infrared spectral range by tomosynthesis. Transmittance data are obtained for a large number of oblique projection directions by scanning a cw laser source across the surface of the slab and by using a CCD camera for spatially resolved light detection. A perturbation model of light transport is used to convert the intensity maps for the different projections into absorption maps.
View Article and Find Full Text PDFNon-invasive depth determination of inclusion in biological tissues using spatially offset Raman spectroscopy with external calibration.
Analyst
November 2020
Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, UK Research and Innovation, Harwell Campus OX11 0QX, UK.
Spatially offset Raman spectroscopy (SORS) allows chemical characterisation of biological tissues at depths of up to two orders of magnitude greater than conventional Raman spectroscopy. In this study, we demonstrate the use of SORS for the non-invasive prediction of depth of an inclusion within turbid media (e.g.
View Article and Find Full Text PDFNumerical reconstruction of turbid slab optical properties using global optimization algorithms.
Lasers Med Sci
February 2021
School of Mechanical Engineering, National Engineering Laboratory for Automotive Electronic Control Technology, Shanghai Jiao Tong University, Shanghai, 200240, China.
The detection and reconstruction of the optical properties within turbid slabs/plate parallel mediums have been widely investigated for its applications in medical diagnosis, atmosphere detection, etc., where the scattering of light would be expected. Although the scattering signal can be utilized for diagnostics purposes, the multiple scattering in the intermediate scattering regime (with an optical depth ~ 2-9) has posed a remarkable challenge.
View Article and Find Full Text PDFNew nonlocal forward model for diffuse optical tomography.
Biomed Opt Express
December 2019
School of Computer Science, University of Birmingham, Birmingham, UK.
The forward model in diffuse optical tomography (DOT) describes how light propagates through a turbid medium. It is often approximated by a diffusion equation (DE) that is numerically discretized by the classical finite element method (FEM). We propose a nonlocal diffusion equation (NDE) as a new forward model for DOT, the discretization of which is carried out with an efficient graph-based numerical method (GNM).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!