Multispectral Endoscopes for Early Cancer Detection
Loading...
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Cambridge
Department of Physics
Department of Physics
Abstract
Description
Barrett's Oesophagus is a largely benign disease, resulting from recurring acid reflux. In some cases, Barrett's can develop into cancer, with the risk of progression increasing with the presence of abnormal lesions called `dysplasia'. The standard of care for Barrett's is endoscopic surveillance, using a combination of white light imaging (which captures red, green and blue reflected light to mimic human vision), targeted biopsies of suspicious lesions, and systematic biopsies across the full Barrett's area. Dysplasia or cancer can be curatively resected via an endoscope, provided they can be seen, but miss rates remain high, particularly for early dysplasia. This thesis focuses on the development of novel multispectral endoscopes for enhancing the contrast of dysplasia and early cancer in Barrett's, addressing both practical implementation and assessment of clinical benefit.\\
First, a prototype snapshot multispectral sensor (BioMSFA) is presented, which uses targeted spectral bands to measure blood oximetry and near-infrared (NIR) fluorescence while retaining the ability to produce familiar RGB images. The BioMSFA design is compatible with scalable chip-on-tip endoscope manufacture, to reduce technical barriers to adoption. The BioMSFA was shown to have spatial resolution exceeding commercial multispectral sensors, was able to distinguish blood samples of 30-100\% oxygenation saturation (matching the performance of transmission spectroscopy), and was able to create a false colour video mapping of in vivo blood perfusion. NIR fluorescence was detected for 1000$mu$M concentrations of ICG, with methods proposed for enhancing detection limits for lower concentrations using only external supplementary optics.\\
Second, a current in vivo clinical trial is introduced, which uses swept hyperspectral illumination through a clinical endoscope to capture spectral images in patients undergoing Barrett's surveillance. This thesis focusses on the engineering, characterisation and technical development of the retrofit endoscope, and the optimised hyperspectral sweep. Preliminary in vivo data is presented from the first four patients.