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Proceedings Paper

Chromophore detection by fluorescence spectroscopy in tissue-like phantoms
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Paper Abstract

In the near-infrared spectral region (700 - 900 nm) light penetrates a few centimeters into tissues and hemoglobin dominates the absorption. Consequently, in vivo near-infrared tissue absorption spectroscopy becomes difficult for endogenous compounds of biological interest other than hemoglobin. Exogenous chromophore detection by fluorescence spectroscopy has the potential to provide enhanced sensitivity and specificity for in vivo optical tissue spectroscopy, facilitating the study of many important metabolites in tissues other than hemoglobin. We have performed measurements of the dc fluorescence intensity generated by a fluorophore (rhodamine B) homogeneously dissolved inside a highly scattering tissue-simulating phantom (aqueous suspension of titanium-dioxide particles). The phantom was prepared with optical coefficients (absorption and reduced scattering) similar to those of tissue in the near-infrared; these coefficients were measured with a frequency-domain spectrometer. Measurable dc fluorescence intensity signals from 1 nM rhodamine concentrations inside the phantom are reported. Furthermore, we were able to resolve changes in rhodamine concentration on the order of 1% using the dc fluorescence intensity. This dc fluorescence sensitivity is characterized experimentally at two concentrations (55 and 360 nM) and over a range of source-detector separations. Other aspects of the sensitivity are discussed over a large range of concentrations using a fluorescence photon migration model.

Paper Details

Date Published: 18 August 1997
PDF: 12 pages
Proc. SPIE 2979, Optical Tomography and Spectroscopy of Tissue: Theory, Instrumentation, Model, and Human Studies II, (18 August 1997); doi: 10.1117/12.280240
Show Author Affiliations
Albert E. Cerussi, Univ. of Illinois/Urbana-Champaign (United States)
Sergio Fantini, Univ. of Illinois/Urbana-Champaign (United States)
John S. Maier, Univ. of Illinois/Urbana-Champaign (United States)
William W. Mantulin, Univ. of Illinois/Urbana-Champaign (United States)
Enrico Gratton, Univ. of Illinois/Urbana-Champaign (United States)


Published in SPIE Proceedings Vol. 2979:
Optical Tomography and Spectroscopy of Tissue: Theory, Instrumentation, Model, and Human Studies II
Britton Chance; Robert R. Alfano, Editor(s)

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