Fluorescence attenuated by a thick scattering medium: Theory, simulations and experiments

J Biophotonics. 2023 Jun;16(6):e202300045. doi: 10.1002/jbio.202300045. Epub 2023 Mar 21.

Abstract

Fluorescence-based imaging has an enormous impact on our understanding of biological systems. However, in vivo fluorescence imaging is greatly influenced by tissue scattering. A better understanding of this dependence can improve the potential of noninvasive in vivo fluorescence imaging. In this article, we present a diffusion model, based on an existing master-slave model, of isotropic point sources imbedded in a scattering slab, representing fluorophores within a tissue. The model was compared with Monte Carlo simulations and measurements of a fluorescent slide measured through tissue-like phantoms with different reduced scattering coefficients (0.5-2.5 mm-1 ) and thicknesses (0.5-5 mm). Results show a good correlation between our suggested theory, simulations and experiments; while the fluorescence intensity decays as the slab's scattering and thickness increase, the decay rate decreases as the reduced scattering coefficient increases in a counterintuitive manner, suggesting fewer fluorescence artifacts from deep within the tissue in highly scattering media.

Keywords: fluorescence imaging; fluorescence intensity; photon diffusion.

MeSH terms

  • Computer Simulation
  • Fluorescent Dyes*
  • Monte Carlo Method
  • Phantoms, Imaging
  • Scattering, Radiation

Substances

  • Fluorescent Dyes