Thematic Program of the
1st Canterbury Workshop on OCT and AO
8-10 Sept. 2008
University of Kent, CT2 7NH, UK
For the order of presentations, please see the document:
Workshop schedule
OCT in microscopy
Invited: Gabor Domain Optical Coherence Microscopy
Jannick P. Rolland*, Panomsak Meemon, Supraja Murali, and Kye-sung Lee
CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, FL 32816
*Corresponding author:
Optical Coherence Microscopy (OCM) is an emerging technology capable of depth sectioning of biological tissue at the micrometer scale. In this paper, we propose a developing technology called Gabor Domain Optical Coherence Microscopy (GD-OCM), whose innovation is two folds: (1) A high lateral resolution optical design of a dynamic-focusing optical probe with no moving parts, which provides an invariant resolution of currently 3 mm and up to 2mm full-field of view and 2mm imaging depth by design; (2) An acquisition scheme (using the probe) that is capable of performing automatic data fusion to render an in-focus high resolution image throughout the depth of sample at in vivo speeds.
Imaging of Cardiovascular Dynamics in Early Mouse Embryos with Swept Source Optical Coherence Tomography
Kirill V. Larin1,*, Irina V. Larina2, and Mary E. Dickinson2
1Biomedical Engineering Program, University of Houston,
Houston, TX 77204, USA
2Department Molecular Physiology and Biophysics, Baylor College of Medicine,
Houston, TX 77584, USA
*Contact email:
Congenital cardiovascular defects are very common, occurring in 1% of live births, and cardiovascular failures are the leading cause of birth defect-related deaths in infants. To improve diagnostics, prevention and treatment of cardiovascular abnormalities, we need to understand not only how cells form the heart and vessels but also how physical factors such as heart contraction and blood flow influence heart development and changes in the circulatory network. Mouse models are an excellent resource for studying cardiovascular development and disease because of the resemblance to humans, rapid generation time, and availability of mutants with cardiovascular defects linked to human diseases. In this work, we present results on development and application of Doppler Swept Source Optical Coherence Tomography (DSS-OCT) for imaging of cardiovascular dynamics and blood flow in the mouse embryonic heart and vessels. Our studies demonstrated that the spatial and temporal resolution of the DSS-OCT makes it possible to perform sensitive
measurements of heart and vessel wall movements and to investigate how contractile waves facilitate the movement of blood through the circulatory system.
In-Vivo Imaging of Adult Zebrafish Using Optical Coherence Tomography
Y. Verma , K. Divakar Rao, and P. K. Gupta
Laser Biomedical Applications and Instrumentation Division
Raja Ramanna Centre for Advanced Technology
Indore, India-452013,
Zebrafish (Danio rerio) a vertebrate is a good model system in medical research to understand a variety of human biological processes. These studies often require measurements of the morphological and physiological parameters of Zebrafish. Therefore, development of noninvasive imaging techniques for this purpose is of considerable interest. In this article, we present a brief overview of use of OCT for noninvasive in-vivo imaging of adult Zebrafish.
Using en-face optical coherence tomography to analyse gene function
in Drosophila Melanogaster larval heart
Adrian Bradu1, Lisha Ma2, Jim Bloor2 and Adrian Podoleanu1
1 Applied Optics Group, School of Physical Sciences, University of Kent, CT2 7NH, Canterbury, United
Kingdom
2 Cell Biology & Developmental Group, Department of Biosciences, University of Kent, CT2 7NJ,
Canterbury, United Kingdom
In-vivo Optical Coherence Tomography (OCT) imaging of the fruit fly Drosophila Melanogaster larval heart allows non invasive visualizations and assessment of its cardiac function. In order to image Drosophila heart, we have developed a dedicated imaging instrument able to provide simultaneous OCT and Laser Scanning Confocal Microscopy (LSCM) images. With this dual imaging system, the heart can easily be located and visualised within the specimen and the change of the heart shape in a cardiac cycle monitored. Here we have used targeted gene expression to knockdown the myospheroid (mys) gene in the larval heart using a specific RNAi construct. By knocking down a β integrin subunit encoded by mys we have recorded an enlarged heart chamber in both diastolic and systolic states. Also, the fraction of reduction of the chamber diameter was smaller in the knockdown heart. These phenotypic differences indicate that impaired cardiac contractility occurs in the heart where the integrin gene express level is reduced. At our knowledge, this is for the first time when it is shown that integrins have a direct relationship to a dilated heart defect.
En-face OCT microscope at 1060 nm
Liviu Neagu1, Antonio B. Lobo Ribeiro2, Jose Salcedo2,Adrian Bradu1, Lisha Ma3, Jim Bloor3,
Adrian Podoleanu1
1 Applied Optics Group, University of Kent, Canterbury, UK
2 Multiwave Photonics, Porto, Portugal
3 Department of Biosciences, University of Kent, Canterbury, UK
A microscope system has been devised which implements a dual channel OCT and confocal microscope. The configuration is driven by a novel broadband fibre source centred at 1060 nm wavelength (Multiwave Photonics). The dual channel configuration has been designed and constructed to acquire live images from scattering biological samples. The configuration consists in an optical circulator and at least two couplers in a symmetric arrangement for the object and reference arm. The OCT channel microscope is based on a Mach-Zehnder interferometer configuration. Each arm of the interferometer contains an in- fibre acousto-optic modulator. One of the in-fibre acousto-optic modulator is driven at a fixed frequency of 40 MHz and the other via an RF Function Generation, with adjustable frequency. In this way, the carrier frequency can be conveniently changed in the range 100 kHz to 1.5 MHz. Light retroreflected by the sample is sent to a balanced coupler where it interferes with the reference beam. The interference signal is photodetected using two photodetectors followed by a differential amplifier.
OCT in the clinic
Invited: Anatomical optical coherence tomography of the upper and lower airway
D. D. Sampson
Anatomical optical coherence tomography (aOCT) is an endoscopic optical technique that enables continuous, quantitative assessment of hollow organ size and shape in three dimensions - at the bedside and in the operating theatre. It is a powerful alternative to X-ray computed tomography, magnetic resonance imaging, and other indirect methods for the assessment of hollow-organ anatomy. We will describe examples of clinical research underway with aOCT in the upper and lower airway. In the upper airway, this includes studies in sleep apnoea, such as evaluation of changes in pharyngeal shape and size in individuals with and without obstructive sleep apnoea, including the effect of body posture. In the lower airway, we demonstrate the capacity of aOCT to usefully determine stent size in the theatre during treatment of lower airway obstruction in a range of patients, as well as the ability to perform regional compliance measurements. The capacity of aOCT to monitor dynamic breathing-related changes in airway shape and size will be demonstrated. Technical issues, including the incidence of incomplete data due to shadowing or low signal-to-noise ratio, the necessary measurement range, and limitations caused by motion artefact and means of addressing it, will be described. Finally examples of three-dimensional anatomical reconstruction will be given.
A 3-Dimensional Skin Imaging System Designed by
Full-Colored Optical Coherence Tomography in conventional Hand-Held Model
Bor-Wen Yang (1), Li-Ming Chan (2), Kai-Cheng Wang (3), Wen-Hsuan Cheng (4)
1 : Department of Opto-Electronic System Engineering, Ming-Hsin University of Science and Technology, Taiwan, R.O.C.
2, 3, 4 : Institute of Electronic Engineering, Ming-Hsin University of Science and Technology, Taiwan, R.O.C.
To take place of normal 2D skin camera, new hand-held imaging system is proposed for 3D skin imaging. With 3 original-colored beams applied in optical coherence tomography, full-colored image is achieved for dermatology.
Can normal lymph node architecture be characterised by optical coherence tomography?
R. A. McLaughlin, L. Scolaro, B. R. Klyen, J. J. Armstrong, S. Hamza, P. Robbins, C. Saunders,
D. D. Sampson, University of Western Australia
Structural Characterization of Hair Fiber by Optical Coherence
Tomography
Freitas, A.Z.1; Velasco, M.V.R.2; Raele, M.P.1; Kaneko, T.M.2; Vieira Jr., N.D.1;
Baby, AR.2
1 Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e
Nucleares (IPEN-CNEN/SP), Brasil
2 Departamento de Farmácia, Faculdade de Ciências Farmacêuticas,
Universidade de São Paulo (FCF-USP), Brasil
In this work we use the OCT technique to produce in vitro transversal section images of human hair. It was possible to identify in the A-scan protocol its principal structures: cuticle, cortex and medulla. The mean diameter of medulla was 29 ± 7 μm and hair diameter was 122 ± 16 μm in our samples of standard Afro-ethnic hair. We also compared the OCT signal before and after chemical treatment with 18% w/w ammonium thioglycolate solution. After chemical treatment, it was not possible to identify the main structures of hair fiber, due the index matching promoted by deleterious action of chemical agent. A tridimensional image was built starting from 601 cross-sectional images (slices). Each slice was taken in steps of 6.0 μm at 8 frames per second, and the whole 3D image was built in 60 seconds.
En-face OCT microleakage investigation after laser-assisted dental hard tissue treatment
Carmen Todea1, Cosmin Balabuc1, Cosmin Sinescu1, Meda Negrutiu1, Laura Filip1, Michael Hughes2, Adrian Bradu2, Adrian Podoleanu2
1School of Dentistry, University of Medicine and Pharmacy of Timisoara, Bvd. Revolutiei 1989 No. 9, 300070, Timisoara, Romania
2University of Kent, School of Physical Sciences, Applied Optics Group, Canterbury, CT2 7NH United Kingdom
Purpose: To investigate using en-face Optical Coherence Tomography (OCT) the microleakage after Er:YAG laser cavity preparation.
Material and Methods: Thirty single- and multi-rooted freshly extracted human teeth divided into two study groups, group I (laser) and group II (control), were used in this study. In group I, Class V cavities were prepared using laser on the buccal surface of each tooth. The laser device used was an Er:YAG laser (2940 nm, VSP, 250-320 mJ, 10-20 Hz). In group II, cavities were prepared conventionally and acid etched on the oral surface of the same tooth. All cavities were filled with composite resin. The cavity microleakage was investigated using en-face Optical Coherence Tomography prototype, based on transverse scanning and operating at 1300 nm.
Results: The investigation demonstrated qualitatively the reduction of microleakage in cavities prepared with Er:YAG laser as compared to the control group, in which cavities were prepared conventionally.
Conclusion: The en-face OCT method provided a superior non-invasive and real time investigation method, thus reducing the occurrence of secondary caries by early detection. Moreover, based on the results of this investigation, it may be concluded that Er:YAG laser-assisted cavity preparation leads to reduction of microleakage.
Optical coherence tomography and confocal microscopy investigations of dental prostheses
Meda L.Negrutiua, Cosmin Sinescua, Michael Hughesb, Adrian Bradub, Mihai Rominua, Carmen Todeac, George Dobreb and Adrian Gh. Podoleanub
a Department of Prostheses Technology and Dental Materials, Faculty of Dental Medicine, University of Medicine and Pharmacy "Victor Babeş" Timişoara, Romania
bApplied Optics Group, School of Physical Sciences, University of Kent, Canterbury, UK
c Department of Oral Rehabilitation and Dental Emergencies, Faculty of Dental Medicine, University of Medicine and Pharmacy "Victor Babeş" Timişoara, Romania
d Department of Strength of Materials, Politehnica University Timişoara, Romania
Dental prostheses are very complex systems, heterogenous in structure, made up from various materials, with different physical properties. An essential question mark is on the physical, chemical and mechanical compatibility between these materials. They have to satisfy high stress requirements as well as esthetic challanges. The masticatory stress may induce fractures of the prostheses, which may be triggered by initial materials defects or by alterations of the technological process. The failures of dental prostheses lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of en-face optical coherence tomography as a possible non-invasive high resolution method in supplying the necessary information on the material defects of dental prostheses and microleakage at prosthetic interfaces. C-scan and B-scan OCT images as well as confocal images are acquired from a large range of samples. Gaps between the dental interfaces and material defects are clearly exposed. We conclude that OCT can successfully be used as a noninvasive analysis method.
An Innovative Approach for Investigating the Ceramic Bracket-Enamel Interface – Optical Coherence
Tomography and Confocal Microscopy
Roxana Otilia Romînu1, Cosmin Sinescu1, Mihai Romînu1, Meda Negruþiu1, Phillippe Laissue2, Sorin Mihali3, Michael Hughes4, Adrian Bradu4, Adrian Gh. Podoleanu4
1 “Victor Babes” University of Medicine and Pharmacy,School of Dentistry, Department of Prostheses
Technology and Dental Materials
2 Kent Institute of Medical Science, University of Kent, Canterbury, UK
3 student, “Victor Babes”University of Medicine and
Pharmacy Timisoara, School of Dentistry
4 Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury, UK
Combining Optical Coherence Tomography and Confocal Microscopy Investigation of the defects inside the Ceramic Fixed Partial Dentures
Cosmin Sinescu1, Meda Negruþiu1, Mihai Romînu1, Phillippe Laissue2, Cezar Clonda3, Michael Hughes4,
Adrian Bradu4, George Dobre4, Adrian Gh. Podoleanu4
1 “Victor Babes” University of Medicine and Pharmacy,School of Dentistry, Department of Prostheses
Technology and Dental Materials
2 Kent Institute of Medical Science, University of Kent, Canterbury, UK
3 student, “Victor Babes”University of Medicine and
Pharmacy Timisoara, School of Dentistry
4 Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury, UK
OCT technology
Analysis of extinction and flow velocity with joint Spectral and Time domain OCT
Szymon Tamborski_,Maciej Szkulmowski, Anna Szkulmowska, Andrzej Kowalczyk, Maciej Wojtkowski
Authors’ affiliation: Institute of Physics, Nicolaus Copernicus University, ul. Grudziądzka 5, PL–87-100 Toruń, Poland
Optical Coherence Tomography in both Spectral and Time domain variants has become an exceptionally useful tool for retrieval of structural information of diverse media of sufficient scattering properties. Advantages of its applications are taken especially in circumstances where non-invasive in situ and in vivo imaging techniques are desired. Moreover, the great potential which lies in coding information in properties of laser light scattered back from the inside of the object under investigation gives a possibility of gaining much more information than just structural. In this contribution the recipe is presented how to make use of it to get both depth dependent extinction and velocity of flows. In the presented method, which takes advantages of both Spectral and Time domain OCT variants, spectral fringe patterns of sufficient number are acquired in time increments for the fixed point of the sample. This enables estimation of an axial component of a flow velocity vector from Doppler beating signal. On the other hand, FT−1 of measured signal followed by windowed FT returns light spectrum as a function of an axial coordinate. From such data spatial distribution of extinction coefficient may be determined providing additional characteristics of the medium. In this contribution the details of the theory of this spectroscopic OCT analysis as well as flow velocity measurement technique are followed by the demonstration and comments on experimental results.