Recently, the application of both time- and frequency- resolved fluorescence techniques for the determination of photon migration characteristics in strongly scattering media has been used to characterize the optical properties in strongly scattering media. Specifically, Chance and coworkers have utilized measurement of photon migration characteristics to determine tissue hemoglobin absorbance and ultimately oxygenation status in homogeneous tissues. In this study, we present simulation results and experimental measurements for both techniques to show the capacity of time-dependent photon migration characteristics to image optically obscure absorbers located in strongly scattering media. The applications of time-dependent photon imaging in the biomedical community include imaging of light absorbing hematomas, tumors, hypoxic tissue volumes, and other tissue abnormalities. Herein, we show that the time-resolved parameter of mean photon path length, <L<, and the frequency- resolved parameter of phase-shift, 0, can be used similarly to obtain three dimensional information of absorber position from two-dimensional measurements. Finally, we show that unlike imaging techniques that monitor the intensity of light without regard to the migration characteristics, the resolution of time-dependent photon migration measurements is enhanced by tissue scattering, further potentiating their use for biomedical imaging.

Date Published: 1 February 1992
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Proc. SPIE 1599, Recent Advances in the Uses of Light in Physics, Chemistry, Engineering, and Medicine, (1 February 1992); doi: 10.1117/12.2322292

Published in SPIE Proceedings Vol. 1599:
Recent Advances in the Uses of Light in Physics, Chemistry, Engineering, and Medicine