Scientific Results

Real‐time fiber‐based fluorescence lifetime imaging with synchronous external illumination: A new path for clinical translation

Year: 2019

Authors: Lagarto JL., Shcheslavskiy V., Pavone FS., Cicchi R.

Autors Affiliation: 1National Institute of Optics, National
Research Council (INO-CNR), Sesto
Fiorentino, Italy
2European Laboratory for Non-linear
Spectroscopy (LENS), Sesto Fiorentino,
Italy
3Becker & Hickl GmbH, Berlin, Germany
4Department of Physics, University of
Florence, Sesto Fiorentino, Italy

Abstract: Time-correlated single photon counting
is the “gold-standard” method for fluorescence
lifetime measurements and has demonstrated
potential for clinical deployment.
However, the translation of the technology
into clinic is hindered by the use of ultrasensitive detectors, which make
the fluorescence acquisition impractical with bright lighting conditions such
as in clinical settings. We address this limitation by interleaving periodic fluorescence
detection with synchronous out-of-phase externally modulated light
source, thus guaranteeing specimen illumination and a fluorescence signal
free from bright background light upon temporal separation. Fluorescence
lifetime maps are generated in real-time from single-point measurements by
tracking a reference beam and using the phasor approach. We demonstrate
the feasibility and practicality of this technique in a number of biological
specimens, including real-time mapping of degraded articular cartilage. This
method is compatible and can be integrated with existing clinical microscopic,
endoscopic and robotic modalities, thus offering a new pathway
towards label-free diagnostics and surgical guidance in a number of clinical
applications.

Journal/Review: JOURNAL OF BIOPHOTONICS

Volume: 12      Pages from: e201960119  to: e201960119

KeyWords: fiber optics, fluorescence lifetime imaging, phasors, surgical guidance, TCSPC, tissue
spectroscopy
DOI: 10.1002/jbio.201960119