Confocal fluorescence high resolution imaging during standard endoscopic procedures has been presented as a very
promising tool to enhance patient care and physician practice by providing supplementary diagnostic information in
real-time. The purpose of this paper is to show not only potential, but convincing results of endoscopic microscopy using
a catheter-based approach.
Mauna Kea Technologies' core technology, Cellvizio, delivers dynamic imaging at 12 frames/second using confocal
miniprobes inserted through the operating channel of regular endoscopes. Cellvizio is composed of 3 parts including
(a) a Laser Scanning Unit, (b) Confocal MiniprobeTM with the following characteristics: 5-15 &mgr;m axial resolution, 2-5
&mgr;m lateral resolution, 15-100 &mgr;m depth of penetration, field of view of 600x500 &mgr;m and (c) a software package with onthe-
fly processing capabilities.
With several tens of patients examined during routine GI endoscopy procedures, the most relevant clinical parameters
could be assessed in a doubled-blinded fashion between the endoscopist and a pathologist and results showing very high
accuracy in the differentiation of neoplasia from normal and hyperplastic tissue were obtained.
In the field of pulmonology, the micro-autofluorescence properties of tissues could be assessed and structures never before
accessed in vivo were observed. Cellvizio® may be useful to study bronchial remodeling in asthma and chronic obstructive
pulmonary diseases. Using appropriate topical fluorescent dye, the Confocal Miniprobes may also make it possible
to perform optical biopsy of precancerous and superficial bronchial cancers.
Cellvizio® is as a new tool towards "targeted biopsies", leading to earlier, more reliable and cost effective diagnostic
procedures. Other applications, specifically in molecular imaging are also made possible by the miniaturization of the
probe (combination with biopsy needle for solid organs use or lymph node detection) and by the compatibility of the
system with other imaging modalities (auto-fluorescence and narrow-band imaging endoscopy, MRI, PET, etc).
The purpose of this paper is to demonstrate potential for high resolution fluorescence imaging during standard endoscopic
procedures using a catheter-based confocal endoscope, compatible with standard video-endoscopes. The instrument,
an F400 prototype from Mauna Kea Technologies (Paris, France), may function in various imaging modalities: auto-fluorescence or exogenous fluorescence using topical applications of fluorophores.
The system is composed of a Laser Scanning Unit, a range of fibered objectives and a dedicated software, which makes it possible to obtain images at a rate of 12 frames per second. These images have a lateral resolution of 2.5 microns, an axial resolution of 15 microns, a field of view up to 600 microns x 500 microns and can be obtained at depths up to 100 microns. The miniaturized fibered probes offer unique access capabilities, specifically through the operating channel of an endoscope. So far, these studies have demonstrated the safety and efficacy of the F400 in allowing confocal laser imaging of the internal microstructure of tissues in the anatomical tract accessed by the endoscope, thanks to the miniaturization of the
system. The device can be considered as a new tool towards "optical biopsies" and in vivo histology, leading to more physiologically relevant data and cost effective medicine.
This paper presents a novel fibered confocal reflectance microscopy system (FCRM) specifically designed for the medical observation of biological tissues in vivo and in situ, in real time, at the cellular level: the R-600. Reflectance imaging is based on the refraction index difference between biological components while confocal imaging allow to perform the optical sectioning slice in-depth inside the tissues. The R-600 is based on a proximal scanning system, coupled with a 7 mm diameter probe made of tens of thousands of flexible optical fibers allowing in situ imaging, associated with a dedicated software performing real-time control and image processing. The R-600 provides 12 frames per second at an optical imaging depth of 30 microns, with a high lateral resolution, 1 micron, an axial resolution of 2 microns in a field of view 160 microns in diameter.
Thanks to the miniaturization of the optical probe, unprecedented accessibility is made possible in organs such as the cervix or the otolaryngological sphere, in a completely non-invasive fashion. The aim of FCRM is to perform optical biopsy. As a first step towards this goal, we present here results obtained in vivo and in real-time on a human mouth , assessing the ability of the R-600 to perform rapid morphologic examination. Subcellular structures such as nuclei and membranes can be clearly distinguished on the images. Further miniaturization opens perspectives for an integrated endoscope-compatible system with broad medical applications.
The SIM metrology subsystem utilizes cornercube retroreflectors as fiducials. These components will introduce errors in the metrology output that must be quantified. Eventually, a complete modeling of the metrology subsystem will be needed. For that purpose, we are developing an optical model for a cornercube retroreflector, taking into account most of the defects present in such an optical part. Our goal is to given a phase map of the wavefront produced by the interference of the reference beam and the metrology beam. Our first step towards this goal is the construction of an optical model and its validation, using the MACOS and VSIM packages.
Carbon single walled nanotubes produced in high yields by the electric arc technique have been studied by several techniques including HRTEM. It is shown in particular that they have a narrow diameter distribution around an average value of 1.3 nm. In this paper, we mainly report characterization results obtained by high resolution Raman spectroscopy. Raman spectra exhibit a very rich structure especially in the low frequency range where several components are observed. Using previous calculations, we attribute the main features to armchair tubes with (6,6) to (12,12) geometry, in agreement with the narrow diameter distribution observed by HRTEM measurements.
GAIA represents a preliminary concept for an astrometric mission being considered in the context of ESA's `Horizon 2000 Plus' long-term scientific program. It comprises three stacked Fizeau interferometers viewing different directions within an instantaneous scanning circle, each interferometer consisting of two 50 cm aperture mirrors with a baseline separation of 2.5 m. Equipped with a modulating grid, and using CCDs, at least as the baseline detector, repeated scanning of the celestial sphere over a period of five years is estimated to lead to positions, proper motions, and parallaxes of some 50 million objects, down to about V equals 15 mag, with an accuracy of better than 10 microarcsec, along with multi-color multi-epoch photometry of each object. The scientific case for such a mission is compelling: distances and kinematical motions for objects throughout our Galaxy would be obtained, along with valuable information on the space-time metric ((gamma) ), angular diameters of hundreds of stars, and a vast body of information on double and multiple systems. Screening of all 100,000 stars within 100 pc for periodic photocentric motions would provide the most powerful and systematic method of detecting possible planetary companions proposed to date.
We present a method for performing global astrometry with the proposed Orbiting Stellar Interferometer. Because it is dedicated to wide-angle astrometry, OSI has the intrinsic capabilities to achieve global astrometry, even though it doesn't measure directly relative angles between pairs of stars, such as HIPPARCOS. In this paper, a time-independent model is shown, leading to a coherent solution for the positions of reference stars on the whole sky. With an initial measurement accuracy of 10 micro-arcseconds, corresponding to an accuracy of 340 picometers in the knowledge of the delay-line position of the observing interferometer, the consistent least-squares solution gives an accuracy by which the astrometric parameters can be obtained around 2 - 3 micro-arcseconds.
Space-based interferometers dedicated to wide-angle astrometry would dramatically increase the accuracy of angular measurements fundamental to a wide range of astrophysical problems. The proposed Global Astrometric Interferometer for Astrophysics, a continuously rotating instrument comprising two or three interferometers, will reach the 5-20 (mu) as level on more than 35 million objects. The necessary wide field-of-view for such a precision could be obtained with a Fizeau interferometer. We propose a design for a 2.6 m baseline interferometer with two 0.5 m apertures, and overal dimensions compatible wiht the size of the Ariane V payload shroud. It has approximately 1 degree diffraction limited field-of-view. The response of the optical system to small perturbations on each optical element is given in terms of fringe visibility, which is shown to depend only on subaperuture spot separation.
We describe a concept for an interferometric space mission dedicated to global (wide-angle) astrometry. The GAIA satellite contains two small (baseline APEQ 3 m) optical interferometers of the Fizeau type, mechanically set at a large and fixed angle to each other. Each interferometer has a field of view of about one degree. Continuous rotation of the whole satellite provides angular connections between the stars passing through the two fields of view. Positions, absolute parallaxes and annual proper motions can be determined with accuracies on the 20 micro-arcsec level. The observing programme may consist of all objects to a limiting magnitude around V = 15-16, including 50 million stars. The GAIA concept, which has been proposed for a Cornerstone Mission within the European Space Agency's long-term science programme, is based on the same general principles as the very successful ESA Hipparcos mission, but takes advantage of the much higher resolution and efficiency permitted by interferometry and modern detector techniques.