Depth resolution and multiexponential lifetime analyses of reflectance-based time-domain fluorescence data

Area of Science:

• Biomedical Optics
• Fluorescence Spectroscopy
• Medical Imaging

Background:

• Time-domain fluorescence imaging offers advanced capabilities beyond conventional methods.
• It can differentiate autofluorescence, quantify multiple fluorophores, and assess tissue microenvironments.
• Reflectance-based systems can also determine inclusion depth using this technique.

Purpose of the Study:

• To develop and validate an improved method for analyzing reflectance-based time-domain fluorescence data.
• To accurately recover mixed concentration ratios of multiple fluorescent agents and their inclusion depth.
• To enhance quantitative analysis in biomedical imaging applications.

Main Methods:

• Theoretical development of an improved data analysis method for reflectance-based time-domain fluorescence.
• Validation through simulations and tissuelike phantom experiments.
• Utilized a short source-detector separation system.

Main Results:

• Accurate recovery of inclusion depth and two-fluorophore concentration ratios up to 1 cm depth with known optical properties.
• Demonstrated the critical importance of depth resolution and accounting for fluorescence lifetime dispersion.
• Successful resolution of three-fluorophore ratios at depth when fluorescence lifetimes are known.

Conclusions:

• The developed method accurately quantifies multiple fluorophores and inclusion depth in time-domain fluorescence imaging.
• Accurate depth and lifetime analysis are crucial for precise ratio recovery.
• This technique holds potential for autofluorescence removal and advanced quantitative analyses like tracer kinetic modeling.