Analytical solutions for time-resolved fluorescence lifetime imaging in a turbid medium such as tissue

Area of Science:

• Biophotonics
• Medical Imaging
• Optical Spectroscopy

Background:

• Fluorophore lifetime imaging (FLIm) is sensitive to local tissue microenvironments.
• Quantifying these lifetime changes in highly scattering tissues is challenging due to light scattering and absorption.
• Distinguishing metabolic perturbations from photon transit time is crucial for accurate FLIm.

Purpose of the Study:

• To develop an analytical solution for quantifying site-specific fluorophore lifetime perturbations in turbid media.
• To differentiate lifetime changes caused by metabolic status from photon transit delays.
• To establish a foundation for practical lifetime imaging in biological tissues.

Main Methods:

• Development of an analytical solution based on random walk theory.
• Incorporation of a priori knowledge of tissue optical properties (scattering and absorption).
• Validation of the analytical solution against numerically solved exact solutions.

Main Results:

• The analytical solution accurately quantifies fluorophore lifetime perturbations in turbid media.
• The method successfully differentiates metabolic-induced lifetime changes from photon transit delays.
• The solution is validated by comparison with exact numerical solutions.

Conclusions:

• The developed analytical solution provides a practical approach for lifetime imaging in turbid media.
• This method can be applied to assess local metabolic status in tissues using FLIm.
• The technique holds promise for advancing non-invasive diagnostic and research applications in biophotonics.