Design of lipid emulsion-dye phantoms for validation of optical imaging systems

Optical phantoms are important for validation of optical imaging systems. The combination of polarized light imaging (PLI) and hyperspectral imaging (HSI) provides a novel tool to study biological and clinical questions. We previously developed a polarized hyperspectral imaging (PHSI) system for cancer detection. In this study, we developed multiple tissue-mimicking lipid emulsion-dye phantoms consisting of one of four dyes and lab-made lipid emulsion (LE) to measure the degree of polarization (DOP) through scattering of LE particles. The LE and dye components validate wavelength dependent changes in polarization within the imaging spectral range of 460 - 600 nm. Varying the LE concentration enabled controlled modulation of scattering strength, allowing systematic evaluation of polarization and reflectance responses. Results showed that these tissue-mimicking dye phantoms, at specific concentrations, produced reflectance and polarization trends that are relevant to the known absorption spectrum of the respective dye. Increased DOP was observed near each dye's absorption maximum, consistent with selective absorption of multiple scattered light. The lab-made lipid emulsion-dye phantom is tunable, has a low cost compared to commercial Intralipid, and can provide a more accessible approach to validating various optical imaging systems.