Session Overview |
Biophotonics - Bloc 3Room: International 2 |
Date: Thursday, June 07 |
08:00 |
Thermophotonic Lock-in Imaging and Spectral-Domain Optical Coherence Tomography as Two Promising Optical-Based Methods in Detection of Early Dental Caries
Main Author: Elnaz Baradaran Shokouhi Organization: York University , Canada Prevalence of dental caries indicates that the current standard of care in Dentistry is not effective. Therefore, Dentistry is shifting to a new paradigm of early diagnosis and management of the carious lesion (i.e., preventive Dentistry). However, the success of this approach depends on the ability of clinical methods in detecting caries at early stages. Since existing clinical detection methods fail in this regard, a variety of optics-based diagnostic techniques have been proposed for detection of caries at early stages. These techniques provide diagnostic contrast based on enhancement of either light scattering (e.g., optical coherent tomography or OCT) or light absorption (e.g., thermophotonic lock-in imaging or TPLI) at early caries. In this work, we present a systematic comparison on the detection performance of OCT and TPLI as two promising early dental caries detection imaging modalities based on light scattering and absorption, respectively. Through controlled demineralization studies on extracted human teeth and μCT validation experiments, performance parameters such as systems’ early caries detection threshold, sensitivity and specificity have been quantified and compared. Results indicate that both light scattering and absorption contrast mechanisms are sensitive to small variations in structure of tooth. However, TPLI exhibits significantly better detection specificity and threshold due to the more specific and molecular-contrast nature of light absorption. OCT, on the other hand, provides three dimensional structures of early caries while TPLI produce depth-integrated and two dimensional images. |
08:15 |
Wide field Raman Imaging System - Ex Vivo Brain Structure Margin Recognition
Main Author: François Daoust Organization: École Polytechnique de Montréal, Canada In brain cancer resection surgery, maximal cancer and minimal normal tissue resection is strongly correlated with patient overall survival. This is because leftover cancer cells can lead to tumor reoccurrence while normal brain is associated with patient mental and motor functions. However, the naked eye and available imaging technologies to guide brain surgeons in the resection of cancerous tissue cannot adequately identify the tumor margins and therefore surgeons tend to leave cancer cells behind. We are presenting the development of a new macroscopic Raman imaging system capable of imaging structural components in ex vivo brain tissue in acquisition times under 30s, over a field of view of 14mm2 with a spatial resolution of 500x500µm2. |
08:30 |
Intracellular refractive index and cell thickness measured with digital holographic microscopy
Main Author: Erik Belanger Organization: Université Laval, Canada A decoupling strategy has been used to measure the intracellular refractive index and cell thickness independently with digital holographic microscopy. The approach has been applied to three different cell types and reveals intracellular RI ranging from 1.35 to 1.39 while cell thickness varied between 1 to 10 microns. In the case of a hypo-osmotic stimulation, cellular swelling was observed and characterized by an increase in cell thickness and a dilution of the intracellular RI. Finally, a hyper-osmotic challenge was also performed and led to cell deflation accompanied by an increase of the intracellular RI. |
08:45 |
Use of a double clad fiber for OCT surveillance of laser therapy using real-time speckle variance
Main Author: Raphaël Maltais-Tariant Organization: École Polytechnique de Montréal, Canada The goal of this project is to create a single-fiber instrument capable of enabling and monitoring laser therapy using OCT to identify coagulated tissues in real-time. Speckle variance monitoring has previously been used in conjunction with OCT to detect and even quantify flow in blood vessels. Similar algorithms have also been used to identify coagulated tissues due to laser therapy, albeit using post-processing of the OCT images acquired during the laser intervention. This project consists in taking this idea a step further by using a double-clad fiber to deliver both the therapy and OCT lasers to the sample. Furthermore, speckle analysis will be performed in real time allowing the identification of coagulated tissues during laser therapy. This will allow for precise distinction between coagulated and untouched tissues. |
09:00 |
High speed, UHR-OCT for in-vivo morphological, functional and vascular imaging of the eye in health and disease
Main Author: Kostadinka Bizheva Organization: University of Waterloo, Canada Potentially blinding diseases that affect different parts of the eye such as the retina, cornea and limbs, cause morphological, vascular and functional changes in the ocular tissue. We have developed high speed, UHR-OCT technology capable of volumetric imaging of the cellular structure of ocular tissue, as well as simultaneous imaging of morphological, vascular and functional changes in the eye induced by various ocular pathologies. |
09:25 |
High power femtosecond Yb:KGW oscillator for wide field SHG microscopy of biological tissues
Main Author: Leonardo Jose Uribe Castano Organization: University of Toronto, Canada We report on the demonstration of a highly efficient semiconductor saturable absorber (SESAM) mode-locked Yb:KGW laser to be used in wide-field second harmonic generation (SHG) microscopy for applications in fast imaging of live samples and large area imaging of histopathology sections. |
09:40 |
Fluorescence Detection of Rare Circulating Cells In Vivo: Technology, Applications and Future Prospects
Main Author: Mark Niedre Organization: Northeastern University, Canada To be announced |
10:05 |
From lab to market: the story of double-clad fiber couplers
Main Author: Caroline Boudoux Organization: École Polytechnique de Montréal, Canada To be announced |