Online multispectral fluorescence lifetime values estimation and overlay onto tissue white-light video frames

Dimitris Gorpas, Dinglong Ma, Julien Bec, Diego R. Yankelevich, Laura Marcu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Fluorescence lifetime imaging has been shown to be a robust technique for biochemical and functional characterization of tissues and to present great potential for intraoperative tissue diagnosis and guidance of surgical procedures. We report a technique for real-time mapping of fluorescence parameters (i.e. lifetime values) onto the location from where the fluorescence measurements were taken. This is achieved by merging a 450 nm aiming beam generated by a diode laser with the excitation light in a single delivery/collection fiber and by continuously imaging the region of interest with a color CMOS camera. The interrogated locations are then extracted from the acquired frames via color-based segmentation of the aiming beam. Assuming a Gaussian profile of the imaged aiming beam, the segmentation results are fitted to ellipses that are dynamically scaled at the full width of three automatically estimated thresholds (50%, 75%, 90%) of the Gaussian distribution's maximum value. This enables the dynamic augmentation of the white-light video frames with the corresponding fluorescence decay parameters. A fluorescence phantom and fresh tissue samples were used to evaluate this method with motorized and hand-held scanning measurements. At 640x512 pixels resolution the area of interest augmented with fluorescence decay parameters can be imaged at an average 34 frames per second. The developed method has the potential to become a valuable tool for real-time display of optical spectroscopy data during continuous scanning applications that subsequently can be used for tissue characterization and diagnosis.

Original languageEnglish (US)
Title of host publicationMolecular-Guided Surgery: Molecules, Devices, and Applications II
ISBN (Electronic)9781628419306
StatePublished - 2016
EventMolecular-Guided Surgery: Molecules, Devices, and Applications II - San Francisco, United States
Duration: Feb 13 2016Feb 14 2016


OtherMolecular-Guided Surgery: Molecules, Devices, and Applications II
Country/TerritoryUnited States
CitySan Francisco


  • breast cancer
  • lifetime
  • Time-resolved fluorescence spectroscopy
  • tumor margins

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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