Related Experiment Video
Updated: Dec 27, 2025
Fluorescence Lifetime Macro Imager for Biomedical Applications
Published on: April 7, 2023
Surgical microscope with integrated fluorescence lifetime imaging for 5-aminolevulinic acid fluorescence-guided
Mikael T Erkkilä1, David Reichert1,2, Nancy Hecker-Denschlag3
1Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria.
Significance:
5-Aminolevulinic acid (5-ALA)-based fluorescence guidance in conventional neurosurgical microscopes is limited to strongly fluorescent tumor tissue. Therefore, more sensitive, intrasurgical 5-ALA fluorescence visualization is needed.
Aim:
Macroscopic fluorescence lifetime imaging (FLIM) was performed ex vivo on 5-ALA-labeled human glioma tissue through a surgical microscope to evaluate its feasibility and to compare it to fluorescence intensity imaging.
Approach:
Frequency-domain FLIM was integrated into a surgical microscope, which enabled parallel wide-field white-light and fluorescence imaging. We first characterized our system and performed imaging of two samples of suspected low-grade glioma, which were compared to histopathology.
Results:
Our imaging system enabled macroscopic FLIM of a 6.5 × 6.5 mm2 field of view at spatial resolutions <20 μm. A frame of 512 × 512 pixels with a lifetime accuracy <1 ns was obtained in 65 s. Compared to conventional fluorescence imaging, FLIM considerably highlighted areas with weak 5-ALA fluorescence, which was in good agreement with histopathology.
Conclusions:
Integration of macroscopic FLIM into a surgical microscope is feasible and a promising method for improved tumor delineation.
