Experimental validation of a recently developed model for single-fiber reflectance spectroscopy.

Abstract

.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 , the absorption coefficient , and the phase function parameter . We validated this model with simulations.Aim: We validate our model experimentally. To prevent overfitting, we investigate the wavelength-dependence of 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% ( and at 500 nm) and eight concentrations of Evans Blue ( to at 605 nm). We parametrize as .Results: Average errors were 7% for , 11% for , and 16% with the parametrization of ; and 7%, 17%, and 16%, respectively, without. The parametrization of improved the fit speed 25 times (94 s to ). 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 parametrization prevents overfitting and speeds up the fit.