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Fluorescence Lifetime Macro Imager for Biomedical Applications
Published on: April 7, 2023
Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM)
J Mizeret1, G Wagnières, T Stepinac
1Institute of Environmental Engineering, Swiss Federal Institute of Technology, CH-1015, Lausanne, Switzerland.
Lasers in Medical Science
|August 31, 2010
Summary
This study introduces fluorescence lifetime imaging (FLI) to enhance early cancer detection. FLI improves contrast in endoscopic fluorescence imaging by analyzing fluorescence lifetime (FLT) variations in tissues.
Area of Science:
- Biomedical Optics
- Medical Imaging
- Cancer Diagnostics
Background:
- Endoscopic fluorescence imaging aids early cancer detection but suffers from poor contrast between healthy and diseased tissues.
- Steady-state fluorescence imaging has limitations in differentiating subtle tissue changes characteristic of early-stage carcinomas.
- Fluorescence lifetime (FLT) is sensitive to the fluorochrome's microenvironment, offering potential for improved contrast.
Purpose of the Study:
- To enhance contrast in endoscopic fluorescence imaging for improved early cancer detection.
- To utilize fluorescence lifetime (FLT) information, beyond simple intensity, for tissue characterization.
- To develop and validate a frequency-domain method for measuring FLT in endoscopic settings.
Main Methods:
- A frequency-domain method using a continuous wave (CW) laser modulated at radio-frequencies was employed.
- Excitation light was delivered via optical fiber, and fluorescence images were captured using an endoscope and a modulated detector (homodyning).
- Apparent FLT images were constructed pixel-by-pixel by recording images at multiple modulation phases, processed at quasi-video frequencies.
Main Results:
- Analytical, simulation, and experimental investigations explored the influence of physical parameters on FLT measurement accuracy.
- The developed method demonstrated the potential for constructing lifetime images of endoscopic sites.
- Preliminary results on human tissues showcased the method's capability to differentiate tissue characteristics.
Conclusions:
- Fluorescence lifetime imaging (FLI) offers a promising approach to overcome the contrast limitations of conventional endoscopic fluorescence imaging.
- The frequency-domain FLT measurement technique is feasible for endoscopic applications and can provide valuable diagnostic information.
- This method holds significant potential for improving the early detection and characterization of cancerous lesions during endoscopy.
