Abstract

A diffusion model of noninvasive absorption spectroscopy was used to determine how the change in signal resulting from a point absorber depends on the position of that absorber relative to the source and detector. This is equivalent to calculating the relative probability that a photon will visit a certain location in tissue before its detection. Experimental mapping of the point-target response in tissue-simulating materials confirmed the accuracy of the model. For steady-state spectroscopy a simple relation was derived between the mean depth visited by detected photons, the source–detector separation, and the optical penetration depth. It was also demonstrated theoretically that combining a pulsed source with time-gated detection provides additional control over the spatial distribution of the photon-visit probability.

© 1995 Optical Society of America

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)

Analysis of layered scattering materials by pulsed photothermal radiometry: application to photon propagation in tissue

I. Alex Vitkin, Brian C. Wilson, and R. Rox Anderson
Appl. Opt. 34(16) 2973-2982 (1995)

Measurements of the optical properties of tissue in conjunction with photodynamic therapy

Annika M. K. Nilsson, Roger Berg, and Stefan Andersson-Engels
Appl. Opt. 34(21) 4609-4619 (1995)

Photon migration in the presence of a single defect: a perturbation analysis

Shechao Feng, Fan-An Zeng, and Britton Chance
Appl. Opt. 34(19) 3826-3837 (1995)

Low-coherence optical tomography in turbid tissue: theoretical analysis

Yingtian Pan, Reginald Birngruber, Jürgen Rosperich, and Ralf Engelhardt
Appl. Opt. 34(28) 6564-6574 (1995)