Fibre-based fluorescence-lifetime imaging microscopy: a real-time biopsy guidance tool for suspected lung cancer

Lung cancer is the most common cause of cancer -related deaths worldwide. Early detection improves outcomes, however, existing sampling techniques are associated with suboptimal diagnostic yield and procedure -related complications. Autofluorescence-based fluorescence -lifetime imaging microscopy (FLIM), a technique which measures endogenous fluorophore decay rates, may aid identification of optimal biopsy sites in suspected lung cancer. Our fibre -based fluorescence -lifetime imaging system, utilising 488 nm excitation, which is deliverable via existing diagnostic platforms, enables real-time visualisation and lifetime analysis of distal alveolar lung structure. We evaluated the diagnostic accuracy of the fibre -based fluorescence -lifetime imaging system to detect changes in fluorescence lifetime in freshly resected ex vivo lung cancer and adjacent healthy tissue as a first step towards future translation. The study compares paired non -small cell lung cancer (NSCLC) and non -cancerous tissues with gold standard diagnostic pathology to assess the performance of the technique. Paired NSCLC and non -cancerous lung tissues were obtained from thoracic resection patients (N=21). A clinically compatible 488 nm fluorescence -lifetime endomicroscopy platform was used to acquire simultaneous fluorescence intensity and lifetime images. Fluorescence lifetimes were calculated using a computationally -lightweight, rapid lifetime determination method. Fluorescence lifetime was significantly reduced in ex vivo lung cancer, compared with non -cancerous lung tissue [mean +/- standard deviation (SD), 1.79 +/- 0.40 vs . 2.15 +/- 0.26 ns, P<0.0001], and fluorescence intensity images demonstrated distortion of alveolar elastin autofluorescence structure. Fibre -based fluorescence -lifetime imaging demonstrated good performance characteristics for distinguishing lung cancer, from adjacent noncancerous tissue, with 81.0% sensitivity and 71.4% specificity. Our novel fibre -based fluorescence -lifetime imaging system, which enables label -free imaging and quantitative lifetime analysis, discriminates ex vivo lung cancer from adjacent healthy tissue. This minimally invasive technique has potential to be translated as a real-time biopsy guidance tool, capable of optimising diagnostic accuracy in lung cancer.