High-speed dual color fluorescence lifetime endomicroscopy for highly-multiplexed pulmonary diagnostic applications and detection of labeled bacteria

TL;DR

This paper introduces a high-speed dual-color fluorescence lifetime endomicroscope capable of real-time, multiplexed pulmonary diagnostics and bacterial detection by combining spectral and lifetime imaging techniques.

Contribution

The authors develop a novel high-speed, multi-channel endomicroscopy system that integrates spectral separation with lifetime measurements for enhanced clinical imaging.

Findings

Achieved 1 FPS imaging with high photon detection efficiency.

Successfully differentiated bacteria from lung autofluorescence.

Demonstrated potential for real-time pulmonary diagnostics.

Abstract

We present a dual color laser scanning endomicroscope capable of fluorescence lifetime endomicroscopy at one frame per second (FPS). The scanning system uses a coherent imaging fiber with 30,000 cores. High-speed lifetime imaging is achieved by distributing the signal over an array of 1024 parallel single-photon avalanche photo--diode detectors (SPADs), minimizing detection dead time maximizing the number of photons detected per excitation pulse without photon pile--up to achieve the high frame rate. Dual color fluorescence imaging is achieved by temporally shifting the dual excitation lasers, with respect to each other, to separate the two spectrally distinct fluorescent decays. Combining the temporal encoding, to provide spectral separation, with lifetime measurements we show a one FPS, multi-channel endomicroscopy platform for clinical applications and diagnosis. We demonstrate the potential of the system by imaging smartprobe-labeled bacteria in ex vivo samples of human lung using lifetime to differentiate bacterial fluorescence from the strong background lung auto--fluorescence which was used to provide structural information.