Abstract

The absorption and scattering coefficient of a macroscopically homogeneous strongly scattering medium (lipid emulsion) containing Methylene Blue is quantitatively measured in the spectral range from 620 to 700 nm. We conduct the measurements in the frequency domain by using a light-emitting diode (LED) whose intensity is modulated at a frequency of 60 MHz. We derive an analytical expression for the absorption and scattering coefficients that is based on a two-distance measurement technique. A comparison with other measurement protocols such as measurement at two modulation frequencies shows that the two-distance method gives a better determination of the scattering and absorption coefficients. This study highlights the efficiency and ease of use of the LED technique, which lends itself to in vivo spectroscopy of biological tissues.

© 1994 Optical Society of America

Influence of a superficial layer in the quantitative spectroscopic study of strongly scattering media

Maria Angela Franceschini, Sergio Fantini, L. Adelina Paunescu, John S. Maier, and Enrico Gratton
Appl. Opt. 37(31) 7447-7458 (1998)

Semi-infinite-geometry boundary problem for light migration in highly scattering media: a frequency-domain study in the diffusion approximation

Sergio Fantini, Maria Angela Franceschini, and Enrico Gratton
J. Opt. Soc. Am. B 11(10) 2128-2138 (1994)

Mathematical model for time-resolved and frequency-domain fluorescence spectroscopy in biological tissues

Michael S. Patterson and Brian W. Pogue
Appl. Opt. 33(10) 1963-1974 (1994)

Frequency-domain method for measuring spectral properties in multiple-scattering media: methemoglobin absorption spectrum in a tissuelike phantom

Joshua B. Fishkin, Peter T. C. So, Albert E. Cerussi, Sergio Fantini, Maria Angela Franceschini, and Enrico Gratton
Appl. Opt. 34(7) 1143-1155 (1995)

Optical properties of highly scattering media determined from changes in attenuation, phase, and modulation depth

Matthias Kohl, Russell Watson, and Mark Cope
Appl. Opt. 36(1) 105-115 (1997)