Large Field of View Scanning Fluorescence Lifetime Imaging System for Multimode Optical Imaging of Small Animals

Area of Science:

• Biomedical Optics
• In Vivo Imaging
• Fluorescence Spectroscopy

Background:

• Fluorescence lifetime imaging (FLIM) aids in distinguishing fluorophores in small animals.
• Large field-of-view (LFOV) FLIM is challenging with femtosecond pulsed lasers, especially for blue light (<500nm) due to tissue scattering and absorption.
• Existing methods struggle to achieve LFOV FLIM for whole-animal imaging.

Purpose of the Study:

• To develop a scanning fluorescence lifetime imaging (SFLIM) system capable of achieving LFOV for small animal imaging.
• To overcome the limitations of blue light excitation in LFOV FLIM systems.
• To provide an alternative method for whole-animal FLIM applications.

Main Methods:

• Implemented a scanning fluorescence lifetime imaging (SFLIM) system.
• Utilized a femtosecond (fs) pulsed laser for tunable fluorophore excitation.
• Employed a cooled CCD camera with an ultra-fast time-gated intensifier and an x-y moving stage for scanning.
• Combined scanned images into a single LFOV image for analysis.

Main Results:

• Successfully demonstrated a SFLIM system for LFOV optical imaging in small animals.
• The system effectively acquired FLIM images with blue light excitation.
• Reconstructed images were comparable to those obtained via spectral imaging.
• The SFLIM system proved effective for whole-animal imaging applications.

Conclusions:

• The developed SFLIM system offers a promising solution for LFOV FLIM in small animals, particularly for blue light excitation.
• This technology enhances the capability for in vivo imaging of fluorophores within small animal models.
• SFLIM provides a viable alternative for applications requiring whole-body fluorescence lifetime measurements.