Full spectrum fluorescence lifetime imaging with 0.5 nm spectral and 50 ps temporal resolution

Abstract

The use of optical techniques to interrogate wide ranging samples from semiconductors to biological tissue for rapid analysis and diagnostics has gained wide adoption over the past decades. The desire to collect ever more spatially, spectrally and temporally detailed optical signatures for sample characterization has specifically driven a sharp rise in new optical microscopy technologies. Here we present a high-speed optical scanning microscope capable of capturing time resolved images across 512 spectral and 32 time channels in a single acquisition with the potential for ~0.2 frames per second (256 × 256 image pixels). Each pixel in the resulting images contains a detailed data cube for the study of diverse time resolved light driven phenomena. This is enabled by integration of system control electronics and on-chip processing which overcomes the challenges presented by high data volume and low imaging speed, often bottlenecks in previous systems.

A layer-level multi-scale architecture for lung cancer classification with fluorescence lifetime imaging endomicroscopy

“…A custom fibre-based FLIM system was deployed to acquire data with various user-specified configurations, including different exposure time and two spectral bands [33]. For online imaging and diagnostic purposes, our custom FLIM imaging system recorded sequences of lifetime images with a resolution of 128 Â 128 pixels, at a frame rate of 9 frames per second, which were aggregated across a line sensor of single-photon detectors [12].…”

“…Here, we introduce our unique dataset of over 100, 000 FLIM images from 18 pairs of normal/cancerous tissues of 18 patients. The images were collected by a custom FLIM system [12,33] aiming for online in-vivo in-situ lung disease diagnostics, with various user-specified configurations. The dataset consists of multi-dimensional images rich in spatial and spectral information, which can reflect the diversity of fluorescence lifetime to a large extent.…”

Fibroblast Activation Protein Specific Optical Imaging in Non-Small Cell Lung Cancer

“…Label free optical imaging modalities have the potential to characterize lung cancer using both optical endomicroscopy and fluorescence lifetime imaging (FLIM) systems ( 36 ). Here we used a clinically approved fluorescence and FLIM imaging system ( 31 ) which was compatible with bronchoscopy, where a fibre can be passed through the working channel to access tumours and lung parenchyma ( Supplementary Figure S5 ). FLIM imaging utilizes the exponential decay rate of the photon emission from the fluorophores (fluorescence lifetime) to create the image, which provides additional data over fluorescence intensity alone.…”

“…The imaging system incorporates a pulsed supercontinuum laser source, in this case tuned for excitation at 488 nm, with an achromatic confocal laser scanning system and a time-resolved spectrometer. This spectrometer contains a 512 channel single photon avalanche diode (SPAD) sensor ( 31 ) allowing for the rapid collection of time resolved spectral fluorescence lifetime data. Fluorescence intensity and lifetime images were collected using an image resolution of 160 x 160 pixels over a 498 – 570 nm spectral range with an exposure time of 13 µs per pixel.…”

Improved Protoporphyrin IX-Guided Neurosurgical Tumor Detection with Frequency-Domain Fluorescence Lifetime Imaging

“…While we employed an off-the-shelf long-pass filter, a bandpass filter with a cut-off at around 715 nm, which is right after the second PpIX emission peak, seems to be the optimal choice for FD-FLIM imaging of PpIX. Spectrally resolved FLIM would be highly beneficial to investigate this in more detail [39]. A valuable additional frequency-domain metric in future studies would be the modulation lifetime τ m [28].…”