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Journal of Biomedical Optics • Open Access

Illumination and fluorescence collection volumes for fiber optic probes in tissue
Author(s): Dean Tai; Darren Hooks; John D. Harvey; Bruce H. Smaill; Christian Soeller

Paper Abstract

Optical fibers can deliver light to, and collect it from, regions deep in tissue. However, reported illumination and fluorescence collection volumes adjacent to the fiber tip have been inconsistent, and systematic data on this topic are not available. Illumination and fluorescence collection profiles were characterized with high spatial resolution for different optical fibers in tissue and various fluids using two-photon flash photolysis and excitation. We confirm that illumination and fluorescence collection volumes for optical fibers are near identical. Collection volume is determined by the core dimensions and numerical aperture (NA) of the fiber and the scattering properties of the medium. For a multimode optical fiber with 100 μm core diam and NA=0.22, 80% of the total fluorescence is collected from a depth of 170 μm in tissue and 465 μm in nonscattering fluid. A semiempirical mathematical description of photon flux adjacent to the fiber tip was also developed and validated. This was used to quantify the extent of temporal blurring associated with propagation of a wavefront of altered fluorescence emission across the region addressed by fiber optic probes. We provide information that will facilitate the design of optical probes for tissue imaging or therapeutic applications.

Paper Details

Date Published: 1 May 2007
PDF: 12 pages
J. Biomed. Opt. 12(3) 034033 doi: 10.1117/1.2750288
Published in: Journal of Biomedical Optics Volume 12, Issue 3
Show Author Affiliations
Dean Tai, The Univ. of Auckland (New Zealand)
Darren Hooks, Univ. of Auckland (New Zealand)
John D. Harvey, The Univ. of Auckland (New Zealand)
Bruce H. Smaill, The Univ. of Auckland (New Zealand)
Christian Soeller, Univ. of Auckland (New Zealand)

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