Conference Agenda

Optical Coherence Tomography (OCT) stands out for its ability to combine the high resolution of

microscopy with the penetration-depth of clinical imaging. However, in practice this is still limited to a few

millimetres. Interestingly, the imaging-depth of the latest swept-source systems is not limited by their spectral

width but by the analog-to-digital sampling rate. In lieu of slow reference arm length adjustments, we leverage

opto-electronic frequency shifting. This allows for depth adjustments on the microsecond timescale and a modest

detector bandwidth of 200 MHz . The opto-electronic scheme immediately gives us access to an 8 mm range,

a fourfold increase over the nominal 2 mm range of the source. Moreover, by circumventing the need for a

mechanical reference arm, changes in the axial displacement of the sample can be compensated in real-time.

This makes it attractive for imaging arbitrarily-curved surfaces. We showcase this with wide-field OCT imaging

of the curved retina.

Autofluorescence spectroscopy has emerged in recent years as a powerful tool to report label-free contrast between normal and diseased tissues. In particular, Fluorescence Lifetime Imaging Microscopy (FLIM) has shown detailed profiles of tissue autofluorescence, enabling more informed and rapid tissue characterization, with the potential for translation from the research labs to bedside. We report here the test of our autofluorescence lifetime imaging probe device on four different clinical cases. More in detail, we examined four biopsies, one from a hepatocellular carcinoma (HCC), another from an intrahepatic cholangiocarcinoma (ICC), one from a gastrointestinal stromal tumor (GIST) and the last one from pancreatic ductal adenocarcinoma (PDCA). The results suggest that our autofluorescence lifetime imaging probe, together with phasor analysis, can offer a real-time tool to observe spectral and lifetime contrast on fresh tissues and, thus, is a suitable candidate for improving in situ tissue diagnostics during surgery.

Current surgical resections for Head and Neck Cancers aim for clear margins to prevent local recurrence. However, up to 20% of cases result in positive margins, with secondary surgery increasing the chances of death after 5 years. We envision a MMF endoscope that collects high resolution images using wavefront shaping to scan a 405 nm beam at the fiber tip and collecting fluorescence intensity and lifetime to map tumor margins and detect residual malignant cells. To address the question whether the information contained in the fluorescence and morphology can be used to classify cancer and normal tissues, we used images acquired with a microscope and artificial neural network. Initial findings show promise to separate cancer from normal tissue when training neural networks on FLIM data. Spatial and temporal resolution and required field of view for effective margin assessment are determined.

In this study, we introduce a novel optical setup tailored for measuring scattering spectra of small biological aggregates with minimal sample volumes. Calibration was achieved using Polystyrene beads (PS beads) based on Mie scattering principles, enabling accurate measurements of scattering intensities. Bovine serum albumin (BSA) served as a model for studying protein aggregation due to its predictable aggregation behaviour at elevated temperatures. Analysis of non-aggregated and aggregated BSA solutions revealed significant differences in particle size, underscoring the setup's capability to detect variations in aggregation states. Key findings demonstrate the system's efficacy in monitoring protein aggregation processes, which is critical for biochemical and pharmaceutical research. The precise calibration method and the use of BSA as a validation tool highlight the setup's sensitivity and accuracy in quantifying changes in particle concentration and size due to aggregation. This study provides a framework for analysing protein aggregation and offers insights into the aggregation's impact on scattering properties.

In this study, we report the results of two non-invasive optical methods, Raman microscopy (RM) and polarization-sensitive digital holographic imaging (PSDHI), for distinguishing prostate cancer cells from healthy ones. RM reveals cancer cells metabolize glucose faster, storing it as fatty acids and cholesteryl esters in lipid droplets (LDs). On the other hand, PSDHI shows significant morphological changes in LDs in glucose-incubated cancer cells, including number, volume, and refractive index. High birefringence in cancer LDs under perpendicular polarizations was observed, enabling fast discrimination with over 90% accuracy. PSDHI results align closely with Raman microscopy, suggesting its potential as a promising, high-speed technique for cancer screening purposes.

Venous thromboembolism (VTE) is a common and serious disease which encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT is created when a blood clot forms in the deep veins of the leg and when the clot migrates through the bloodstream, to lung arteries, it creates a PE. VTE is the third cardiovascular cause of death overall and is responsible for 30000 annual deaths in Europe. After biological and clinical investigation, nearly half of VTE cases have no known origin (idiopathic VTE). Among the patients developing idiopathic VTE, about 30% of them would have a recurrent thromboembolic event, 70% would not be subjected to any recurrence. A balance must be struck between the risks of recurrent thrombosis if anticoagulant treatment is stopped versus the risks of bleeding associated with continued anticoagulation therapy that can go up to the course of decades. The search for new biomarkers allowing to best stear the treatment of patients is thus of major interest. Recent studies seem to link clot’s structure to a risk of recurrence. The aim of our work is to develop an innovative optical method, measuring the evolution of the scattering coefficient of a plasma during ex vivo clot formation.