Time-resolved reflectance: a systematic study for application to the optical characterization of tissues

In principle, the measurement of the time-resolved diffuse reflectance, as interpreted on the basis of the diffusion theory, allows one to determine the optical properties (absorption coefficient μ_α and transport scattering coefficient μ´_s ) of biological materials noninvasively. A system for time-resolved reflectance measurements and its performances are described in detail. An extensive experimental work and a computer simulation characterized the influence of μ_α, μ´ _s, and observation distance on the measurement, and allowed to determine the ranges of μ_α and μ´_s which can be measured reliably (and which include most of the values of interest in biomedical applications). Moreover, on the basis of the experimental and computer work, the optimal experimental parameters can be determined in various situations. The results presented are general and can be extended to different systems of measurement