377 results found
Song L, Elson DS, 2012, Dual wavelength endoscopic laser speckle contrast imaging system for indicating tissue blood flow and oxygenation, Conference on Dynamics and Fluctuations in Biomedical Photonics IX/SPIE Photonics West Conference, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Clancy NT, Li R, Rogers K, et al., 2012, Development and evaluation of a light emitting diode endoscopic light source, Conference on Advanced Biomedical and Clinical Diagnostic Systems X, Publisher: Society of Photo-optical Instrumentation Engineers (SPIE), ISSN: 0277-786X
Clancy NT, Stoyanov D, Yang G-Z, et al., 2012, Stroboscopic illumination scheme for seamless 3D endoscopy, Conference on Advanced Biomedical and Clinical Diagnostic Systems X, Publisher: Society of Photo-optical Instrumentation Engineers (SPIE), ISSN: 0277-786X
Song L, Cheng Y, Li R, et al., 2012, Imaging ultrasound field and shear wave propagation using acousto-optic laser speckle contrast analysis (AO-LASCA), Conference on Photons Plus Ultrasound - Imaging and Sensing/Photonics West BiOS Symposium, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Barriere C, Qi J, Allende PBG, et al., 2012, Multifunctional gold nanorods for image-guided surgery and photothermal therapy, Conference on Plasmonics in Biology and Medicine IX, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Li S, Cheng Y, Elson DS, et al., 2012, Sensing shear waves with a CCD based optical system, IEEE International Ultrasonics Symposium, Publisher: IEEE
Clancy NT, Stoyanov D, Maier-Hein L, et al., 2011, Spectrally-encoded fibre-based structured lighting probe for intraoperative 3D imaging, Biomedical Optics Express, Vol: 2, Pages: 3119-3128, ISSN: 2156-7085
Three dimensional quantification of organ shape and structure during minimally invasive surgery (MIS) could enhance precision by allowing the registration of multi-modal or pre-operative image data (US/MRI/CT) with the live optical image. Structured illumination is one technique to obtain 3D information through the projection of a known pattern onto the tissue, although currently these systems tend to be used only for macroscopic imaging or open procedures rather than in endoscopy. To account for occlusions, where a projected feature may be hidden from view and/or confused with a neighboring point, a flexible multispectral structured illumination probe has been developed that labels each projected point with a specific wavelength using a supercontinuum laser. When imaged by a standard endoscope camera they can then be segmented using their RGB values, and their 3D coordinates calculated after camera calibration. The probe itself is sufficiently small (1.7 mm diameter) to allow it to be used in the biopsy channel of commonly used medical endoscopes. Surgical robots could therefore also employ this technology to solve navigation and visualization problems in MIS, and help to develop advanced surgical procedures such as natural orifice translumenal endoscopic surgery.
Background. Minimally invasive surgical techniques such as single access and natural orifice translumenal endoscopic surgery (NOTES) aim to reduce the number of external scars on the patient but impose restrictions on the space available for the light source within the endoscope and, therefore, the size of the field of view that can be sufficiently illuminated. Materials and Methods. This article presents and compares a number of illumination methods (xenon, light-emitting diodes, laser/phosphor, supercontinuum laser) that could be applied in single-access, robotic, and NOTES procedures. The luminance, spectral content, and intensity profile of each source was measured. Standardized images of each illuminating an abdominal simulator were assessed by a group of surgeons to provide an initial clinical impression. Results. The xenon source was found to have the highest luminance when used with a standard laparoscopic light cable, but this was significantly reduced when used with a small cable suitable for single-access applications. The supercontinuum laser–based light source had brightness comparable to the xenon, which was supported by the surgical test group observations. Conclusions. The supercontinuum fiber probe is a potential alternative to xenon light sources for use in single-access surgery with its comparable luminance, small diameter, flexibility, and even illumination. An initial in vivo test is described, providing a guide for future development
Clancy NT, Mylonas GP, Yang GZ, et al., 2011, Gaze-contingent autofocus system for robotic-assisted minimally invasive surgery, EMBC 2011
A gaze-contingent autofocus system using an eye-tracker and liquid lens has been constructed for use with a surgical robot, making it possible to rapidly (within tens of milliseconds) change focus using only eye-control. This paper reports the results of a user test comparing the eye-tracker to a surgical robot’s in-built mechanical focusing system. In the clinical environment, this intuitive interface removes the need for an external mechanical control and improves the speed at which surgeons can make decisions, based on the visible features. Possible applications include microsurgery and gastrointestinal procedures where the object distance changes due to breathing and/or peristalsis.
Garcia-Allende PB, Amygdalos I, Dhanapala H, et al., 2011, Morphological analysis of optical coherence tomography images for automated classiﬁcation of gastrointestinal tissues, Biomedical Optics Express, Vol: 2, Pages: 2821-2836
Elson DS, Li R, Dunsby C, et al., 2011, Ultrasound-mediated optical tomography: a review of current methods, INTERFACE FOCUS, Vol: 1, Pages: 632-648, ISSN: 2042-8898
Sauvage VR, Levene AP, Nguyen HT, et al., 2011, Multi-Excitation Fluorescence Spectroscopy for Analysis of Non-Alcoholic Fatty Liver Disease, LASERS IN SURGERY AND MEDICINE, Vol: 43, Pages: 392-400, ISSN: 0196-8092
Coda S, Kennedy GT, Thompson A, et al., 2011, FLUORESCENCE LIFETIME IMAGING FOR LABEL-FREE CONTRAST OF GASTROINTESTINAL DISEASES, International School of Physics "Enrico Fermi", Course CLXXXI "Microscopy Applied to Biophotonics"
INTRODUCTION: Autofluorescence (AF) has been used to distinguish between normal and diseased tissue, but its molecular basis is still unclear and making quantitative intensity measurements is challenging. Fluorescence lifetime imaging (FLIM) measures the decay rate of the autofluorescent signal from tissue, providing quantitative AF contrast. FLIM has been recently implemented by our group in three endoscopic instruments consisting of a confocal laser endomicroscope, a wide-field fibre-optic endoscope and a single point fibre-optic probe. FLIM has the potential to report on tissue structure and function in real-time during endoscopy, providing a label-free means to detect the early onset of diseases that cause changes in tissue AF. We are developing these 3 modalities for in vivo clinical application, supported by ex vivo studies on freshly-biopsied/resected GI tissues.AIMS & METHODS: The aim of this work is to translate our FLIM instrumentation from the optical bench to in vivo clinical application. AF from 43 endoscopic samples from different GI sites was excited using a conventional confocal FLIM microscope in the range 405-420nm, which is compatible with our FLIM endoscopes, and which is the range needed to excite a number of important endogenous GI tissue fluorophores such as porphyrins, flavins, collagen and elastin. The samples were collected from patients undergoing endoscopy, transported to the FLIM laboratory to be imaged and then submitted for histopathology. The following disorders were investigated: Barrett’s oesophagus, gastric cancer, ulcerative colitis, Crohn’s disease, adenomatous polyps and colon cancer. The accuracy of FLIM in discriminating dysplastic/cancerous samples from normal tissue has been tested by measuring the Area Under the Curve (AUC).RESULTS: Our preliminary data show that premalignant or neoplastic samples display either shorter or longer fluorescence lifetime than that of normal tissue. Increased lifetime val
Clancy NT, Stoyanov D, Yang GZ, et al., 2011, An endoscopic structured lighting probe using spectral encoding, Novel Biophotonic Techniques and Applications
Recovering the three dimensional (3D) surface shape of tissues in minimally invasive surgery (MIS) is important for developing advanced image-guidance and navigation systems. Passive techniques for 3D reconstruction based on computational stereo are limited by the saliency of tissue texture and the view-dependent reflectance characteristics of the scene. Structured lighting provides a viable alternative by projecting known features onto the tissue surface. However, the correspondence problem (distinguishing individual projected features computationally) becomes difficult in tissue due to the presence of occlusions. Furthermore, miniaturisation of a light projection system for use in MIS, while maintaining the required light intensity, is a significant challenge.In this paper, a fibre-based probe is described that projects a spectrally-encoded pattern onto the target surface from its distal end. A dispersed broadband light source is used to project features of varying spectral content. The dominant wavelengths of imaged spots may be deduced from the RGB values of a standard colour camera using an algorithm that locates each colour on a chromaticity diagram. The results show that individual spots of a specified wavelength may be segmented and their centres of mass calculated, despite varying background colour. The probe has also been demonstrated on ex vivo tissue.
Coda S, Kennedy G, Thompson A, et al., 2011, FLUORESCENCE LIFETIME IMAGING OF GASTROINTESTINAL CANCERS, European-Society-for-Medical-Oncology (ESMO) 13th World Congress on Gastrointestinal Cancer, Publisher: OXFORD UNIV PRESS, Pages: v65-v66, ISSN: 0923-7534
Kennedy GT, Munro IH, Coda S, et al., 2011, Fluorescence lifetime imaging endoscopy, European Conference on Biomedical Optics: Clinical and Biomedical Spectroscopy and Imaging II, Publisher: OSA/SPIE
Sun Y, Meier J, Phipps J, et al., 2011, Fluorescence Lifetime Imaging Microscopy (FLIM) for Intraoperative Tumor Delineation: A Study in Patients, Bio-Optics: Design and Application
Li R, Elson DS, Dunsby C, et al., 2011, Effects of acoustic radiation force and shear waves for absorption and stiffness sensing in ultrasound modulated optical tomography., Opt Express, Vol: 19, Pages: 7299-7311
Ultrasound-modulated optical tomography (UOT) combines optical contrast with ultrasound spatial resolution and has great potential for soft tissue functional imaging. One current problem with this technique is the weak optical modulation signal, primarily due to strong optical scattering in diffuse media and minimal acoustically induced modulation. The acoustic radiation force (ARF) can create large particle displacements in tissue and has been shown to be able to improve optical modulation signals. However, shear wave propagation induced by the ARF can be a significant source of nonlocal optical modulation which may reduce UOT spatial resolution and contrast. In this paper, the time evolution of shear waves was examined on tissue mimicking-phantoms exposed to 5 MHz ultrasound and 532 nm optical radiation and measured with a CCD camera. It has been demonstrated that by generating an ARF with an acoustic burst and adjusting both the timing and the exposure time of the CCD measurement, optical contrast and spatial resolution can be improved by ~110% and ~40% respectively when using the ARF rather than 5 MHz ultrasound alone. Furthermore, it has been demonstrated that this technique simultaneously detects both optical and mechanical contrast in the medium and the optical and mechanical contrast can be distinguished by adjusting the CCD exposure time.
Newton RC, Kemp SV, Shah PL, et al., 2011, Progress Toward Optical Biopsy: Bringing the Microscope to the Patient, LUNG, Vol: 189, Pages: 111-119, ISSN: 0341-2040
Sun Y, Sun Y, Stephens D, et al., 2011, Dynamic tissue analysis using time- and wavelength-resolved fluorescence spectroscopy for atherosclerosis diagnosis, OPTICS EXPRESS, Vol: 19, Pages: 3890-3901, ISSN: 1094-4087
Kumar S, Alibhai D, Margineanu A, et al., 2011, FLIM FRET Technology for Drug Discovery: Automated Multiwell-Plate High-Content Analysis, Multiplexed Readouts and Application in Situ, ChemPhysChem, Vol: 12, Pages: 609-626
A fluorescence lifetime imaging (FLIM) technology platform intendedto read out changes in Fçrster resonance energy transfer(FRET) efficiency is presented for the study of protein interactionsacross the drug-discovery pipeline. FLIM provides arobust, inherently ratiometric imaging modality for drug discoverythat could allow the same sensor constructs to betranslated from automated cell-based assays through smalltransparent organisms such as zebrafish to mammals. To thisend, an automated FLIM multiwell-plate reader is described forhigh content analysis of fixed and live cells, tomographic FLIMin zebrafish and FLIM FRET of live cells via confocal endomicroscopy.For cell-based assays, an exemplar application readingout protein aggregation using FLIM FRET is presented, andthe potential for multiple simultaneous FLIM (FRET) readoutsin microscopy is illustrated.
Garcia-Allende PB, Barriere C, Sauvage VS, et al., 2011, Method to determine optimal illumination wavelengths for gold nanoparticle detection in tissue using reflectance spectroscopy, Conference on Clinical and Biomedical Spectroscopy and Imaging II, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Li R, Eckersley R, Dunsby C, et al., 2011, An acoustic radiation force assisted ultrasound modulated optical tomography system, IEEE International Ultrasonics Symposium 2011, Publisher: IEEE
Li R, Eckersley R, Dunsby C, et al., 2011, Optical sensing of shear wave velocity generated by acoustic radiation force, IEEE International Ultrasonics Symposium 2011, Publisher: IEEE
Li R, Elson DS, Dunsby C, et al., 2011, Monte Carlo simulation study of light modulated by acoustic radiation force in elasto-viscous medium, Photonics West: Photons Plus Ultrasound: Imaging and Sensing 2011
Maier-Hein L, Groch A, Haase S, et al., 2011, Markerless augmented reality (AR) guidance with optical techniques for 3D surface reconstruction, Conference of the Society for Medical Innovation and Technology
Song L, Elson D, 2011, Endoscopic laser speckle contrast imaging system using a fibre image guide, Photonics West: Biomedical Applications of Light Scattering V, Publisher: SPIE
McGinty J, Talbot C, Owen D, et al., 2011, Fluorescence Lifetime Imaging Microscopy, Endoscopy and Tomography, Editors: Boas, Pitris, Ramanujam, ISBN: 1420090364
Kar A, Kennedy GT, Coda S, et al., 2011, Real-time optical imaging of bladder cancer using Fluorescence Lifetime Imaging Endoscopy, Hamlyn Symposium on Medical Robotics
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