Experimental Validation Of A Recently Developed Model For Single-Fiber Reflectance Spectroscopy

Significance: We recently developed a model for the reflectance measured with (multi-diameter) single-fiber reflectance (SFR) spectroscopy as a function of the reduced scattering coefficient mu(s)', the absorption coefficient mu(a), and the phase function parameter p(sb). We validated this model with simulations.Aim: We validate our model experimentally. To prevent overfitting, we investigate the wavelength-dependence of p(sb) and propose a parametrization with only three parameters. We also investigate whether this parametrization enables measurements with a single fiber, as opposed to multiple fibers used in multi-diameter SFR (MDSFR).Approach: We validate our model on 16 phantoms with two concentrations of Intralipid-20% (mu(s)' = 13 and 21 cm(-1) at 500 nm) and eight concentrations of Evans Blue (mu(a) = 1 to 20 cm(-1) at 605 nm). We parametrize p(sb) as 10(-5). (p(1)(lambda/650) + p(2)(lambda/650)(2) + p(3)(lambda/650)(3)).Results: Average errors were 7% for mu(s)' 11% for mu(a), and 16% with the parametrization of p(sb); and 7%, 17%, and 16%, respectively, without. The parametrization of p(sb) improved the fit speed 25 times (94 s to <4 s). Average errors for only one fiber were 50%, 33%, and 186%, respectively.Conclusions: Our recently developed model provides accurate results for MDSFR measurements but not for a single fiber. The p(sb) parametrization prevents overfitting and speeds up the fit. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.