Characterization and Application of Angled Fluorescence Laminar Optical Tomography

Abstract

Angled fluorescence laminar optical tomography (aFLOT) is a modified fluorescence tomographic imaging technique that targets the mesoscopic scale (millimeter penetration with resolution in the tens of microns). Traditional FLOT uses multiple detectors to measure a range of scattered fluorescence signals to perform 3D reconstructions. This technology however inherently assumes the sample to be scattering. To extend the capability of FLOT to cover the low scattering regime, the oblique illumination and detection was introduced. The angular degree of freedom for the illumination and detection was theoretically and experimentally investigated. It was concluded that aFLOT enhanced resolution 2.5 times and depth selectivity compared to traditional FLOT, and that it enabled the stacking representation, a process that skips the computationally-intensive reconstruction usually needed to render the tomogram. Because stacking is enabled, the necessity of a reconstruction process is retrospectively discussed. aFLOT systems were constructed and applied in tissue engineering. Phantoms and engineered tissue models were successfully imaged. The aFLOT was shown to perform non-invasive in situ imaging in biologically relevant samples with 1mm penetration and 9-400 micron resolution, depending on the scattering of samples. aFLOT illustrates its potential for studying cell-cell or cell-material interactions.