Fabrication and characterization of phantoms with tissue-like optical properties from 500 to 700nm

A method for the fabrication of phantoms is described based on an epoxy resin system that simulates the optical properties of tissue in the wavelength range 500–700nm. The absorption of the phantoms is determined by two dyes (Epolight 5411 and Epolight 5457; Epolin Inc., Newark, New Jersey) with absorption gradients in the same spectral region as hemoglobin, and the scattering is provided by titanium dioxide particles (Aldrich Chemical, Milwaukee, Wisconsin). The reduced scattering and absorption coefficients were measured using a steady-state spatially resolved reflectance system. The absorption coefficients of phantoms made with both dyes are linear with dye concentration over the entire spectral range. The diffuse reflectance spectra of the phantoms are qualitatively similar to those measured on Caucasian skin in vivo. Both dyes were found to fade during the first three weeks after fabrication, and their long-term stability requires further investigation.