Hyperspectral spatial frequency domain imaging for label-free non-contact and wide-field monitoring of tissue optical properties and chromophore concentrations

Abstract

The Spatial Frequency Domain Imaging (SFDI) is an emerging label-free imaging technique that can provide quantitative chromophore concentrations in tissue. It has been applied to various biomedical scenarios for the mapping of oxy-hemoglobin, deoxy-hemoglobin, water and lipids, including tumor imaging, inflammation monitoring, brown fat identification, blood lipids monitoring, and others. The key to accurate quantification of all four chromophores with near-infrared light is accurate optical absorption measurement at sufficient number of wavelengths, which has been a major challenge. To address this issue, we develop a hyperspectral SFDI system that is able to measure tissue optical properties in the entire 400 – 1000 nm range. With the proposed system, we’ll demonstrate quantitative mapping of tissue water and lipid content using NIR wavelengths rather than the shortwave infrared, which to the best of our knowledge, is unprecedented in the field of Spatial Frequency Domain Imaging.