Annette McWilliams

Integrated endoscopy system for simultaneous imaging and spectroscopy for early lung cancer detection.

An integrated endoscopy system for simultaneous imaging and spectroscopy was developed to facilitate more accurate and convenient detection of early lung cancers. A specially designed three-CCD camera in combination with a dedicated light source permits capture of both white-light color images and tissue autofluorescence images without the need to switch between two different cameras. A mirror with an optical fiber at its center, placed at an interim imaging plane inside the camera unit, facilitates simultaneous imaging and spectroscopy measurements in either white-light reflectance mode or fluorescence mode. The system has been successfully tested in a clinic, demonstrating a practical approach to improve both diagnostic sensitivity and specificity at the same time.

Improvements to a laser Raman spectroscopy system for reducing the false positives of autofluorescence bronchoscopies

Preneoplastic lesions of the bronchial tree have a high probability of developing into malignant tumours. Currently the best method for localizing them for further treatment is a combined white light and autofluorescence bronchoscopy (WLB+AFB). Unfortunately the average specificity from large clinical trials for this combined detection method is low at around 60%, which can result in many false positives. However a recent pilot study showed that adding a point laser Raman spectroscopy (LRS) measurement improved the specificity of detecting lesions with high grade dysplasia or carcinoma in situ to 91% with a sensitivity of 96% compared to WLB+AFB alone. Despite this success, there is still room for much improvement. One constant need is to find better ways to measure the inherently weak Raman emissions in vivo which will result in even better diagnostic sensitivity and specificity. With this aim in mind a new generation Raman system was developed. The system uses the latest charge coupled device (CCD) with low noise, and fast cool down times. A spectrometer was incorporated that was able to measure both the low and high frequency Raman emissions with high resolution. The Raman catheter was also redesigned to include a visible light channel to facilitate the accurate indication of the area being measured. Here the benefits in the adjunct use of LRS to WLB + AFB are presented, and description of the new system and the improvements it offers over the old system are shown.

Lung vasculature imaging using speckle variance optical coherence tomography

Architectural changes in and remodeling of the bronchial and pulmonary vasculature are important pathways in diseases such as asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. However, there is a lack of methods that can find and examine small bronchial vasculature in vivo. Structural lung airway imaging using optical coherence tomography (OCT) has previously been shown to be of great utility in examining bronchial lesions during lung cancer screening under the guidance of autofluorescence bronchoscopy. Using a fiber optic endoscopic OCT probe, we acquire OCT images from in vivo human subjects. The side-looking, circumferentially-scanning probe is inserted down the instrument channel of a standard bronchoscope and manually guided to the imaging location. Multiple images are collected with the probe spinning proximally at 100Hz. Due to friction, the distal end of the probe does not spin perfectly synchronous with the proximal end, resulting in non-uniform rotational distortion (NURD) of the images. First, we apply a correction algorithm to remove NURD. We then use a speckle variance algorithm to identify vasculature. The initial data show a vascaulture density in small human airways similar to what would be expected.

In Vivo Real-time Endoscopic Raman Spectroscopy for Improving Early Lung Cancer Detection

A real-time endoscopic Raman spectroscopy system has been developed that takes 1 second to obtain a spectrum from the human lung in vivo. The system was tested on 80 patients, achieved high diagnostic sensitivity (90%) and good specificity (65%) for lung cancer/precancer detection.

Real-time In Vivo Tissue Raman Spectroscopy for Early Cancer Detection

A platform technology for real-time in vivo tissue Raman spectroscopy was developed that takes 1–2 seconds to obtain a spectrum. The system was tested over 900 skin patients and 80 lung patients, achieved high diagnostic sensitivity (90%) and good specificities (73%, 65%) for skin cancer and lung cancer detection.

Near-infrared Raman spectroscopy detects lung cancer

This work was to explore near-infrared (NIR) Raman spectroscopy for distinguishing tumor from normal bronchial tissue. A rapid NIR Raman system was used for tissue Raman studies. High-quality Raman spectra in the 700-1800 cm-1 range can be acquired from human bronchial tissues in vitro. Raman spectra differed significantly between normal and malignant tumor tissue, with tumors showing increased nucleic acid, tryptophan, phenylalanine signals and decreased phospholipids, proline, and valine signals than normal tissue. Raman spectral shape differences between normal and tumor tissue were also observed particularly in the spectral ranges of 1000-1100, 1200-1400, and 1500-1700 cm-1, which are related to the protein and lipid conformations and CH stretching modes in nucleic acids. The ratio of Raman intensities at 1445 cm-1 to 1655 cm-1 provided good differentiation between normal and malignant bronchial tissue, suggesting that NIR Raman spectroscopy may have a significant potential for the noninvasive diagnosis of lung cancer in vivo based on optical evaluation of biomolecules.