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Proceedings Paper

Spatially-resolved probing of biological phantoms by point-radiance spectroscopy
Author(s): Serge Grabtchak; Tyler J. Palmer; William M. Whelan
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Paper Abstract

Interstitial fiber-optic based strategies for therapy monitoring and assessment rely on detecting treatment-induced changes in the light distribution in biological tissues. We present an optical technique to identify spectrally and spatially specific tissue chromophores in highly scattering turbid media. Typical optical sensors measure non-directional light intensity (i.e. fluence) and require fiber translation (i.e. 3-5 positions), which is difficult to implement clinically. Point radiance spectroscopy is based on directional light collection (i.e. radiance) at a single point with a side-firing fiber that can be rotated up to 360°. A side firing fiber accepts light within a well-defined solid angle thus potentially providing an improved spatial resolution. Experimental measurements were performed using an 800-μm diameter isotropic spherical diffuser coupled to a halogen light source and a 600 μm, ~43° cleaved fiber (i.e. radiance detector). The background liquid-based scattering phantom was fabricated using 1% Intralipid (i.e. scattering medium). Light was collected at 1-5° increments through 360°-segment. Gold nanoparticles, placed into a 3.5 mm diameter capillary tube were used as localized scatterers and absorbers introduced into the liquid phantom both on- and off-axis between source and detector. The localized optical inhomogeneity was detectable as an angular-resolved variation in the radiance polar plots. This technique is being investigated as a non-invasive optical modality for prostate cancer monitoring.

Paper Details

Date Published: 16 February 2011
PDF: 9 pages
Proc. SPIE 7894, Optical Fibers, Sensors, and Devices for Biomedical Diagnostics and Treatment XI, 78940A (16 February 2011); doi: 10.1117/12.874042
Show Author Affiliations
Serge Grabtchak, Univ. of Prince Edward Island (Canada)
Dalhousie Univ. (Canada)
Tyler J. Palmer, Univ. of Prince Edward Island (Canada)
William M. Whelan, Univ. of Prince Edward Island (Canada)
Atlantic Veterinary College (Canada)


Published in SPIE Proceedings Vol. 7894:
Optical Fibers, Sensors, and Devices for Biomedical Diagnostics and Treatment XI
Israel Gannot, Editor(s)

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