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We present two forward-adjoint models for recovering intrinsic fluorescence spectra and hemoglobin oxygen saturation of turbid samples. The first fits measured diffuse reflectance spectra to obtain the absorption and scattering spectra of the medium, and these are then used to correct distortions imposed on the fluorescence spectrum by absorption and scattering. The second fits only the measured fluorescence spectrum to determine simultaneously the amplitudes of absorption and fluorescence basis spectra and scattering parameters. Both methods are validated with Monte Carlo simulations and experimentally in scattering phantoms containing nicotinamide adenine dinucleotide and human erythrocytes. Preliminary measurements from murine tumors in vivo are presented. OCIS codes: 170.3890, 170.6280, 170.6510, 170.7050.

We present a steady-state method for localizing a source of luminescence (i.e., fluorescence or phosphorescence) buried in a semi-infinite turbid medium with unknown optical properties. A diffusion theory expression describing the emittance of an isotropic point source is fit to spatially resolved surface measurements of the diffuse emittance from the luminescent source. The technique reports the location of the center of a 6.0-mm-diameter, fluorophore-containing spherical bulb embedded in a liquid phantom with an accuracy of 1.0 mm or better for source depths as great as 40.0 mm. Monte Carlo data are analyzed to investigate the range and the possible sources of error in the reconstructed source depth.

We present a steady-state radially resolved diffuse reflectance spectrometer capable of measuring the absorption and transport scattering spectra of tissue-simulating phantoms over an adjustable 170-nm wavelength interval in the visible and near infrared. Measurements in a variety of phantoms are demonstrated over the relevant range of tissue optical properties, and the accuracy of the instrument is found to be approximately 10% in both scattering and absorption. Monte Carlo simulations designed to test the accuracy of the instrument are presented that support the experimental findings. Key words: Diffuse reflectance, diffusion theory, Monte Carlo, tissue optics.