Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1999-12-17
2003-06-10
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S478000, C600S116000, C604S101010, C604S102020, C606S192000, C606S015000
Reexamination Certificate
active
06577891
ABSTRACT:
This application claims Paris Convention priority of German patent application 198 59 434.8 filed Dec. 22, 1998, the complete disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The invention concerns a device for the optical-spectroscopic examination of interior surfaces of a body, e.g. of blood vessels, comprising an optical spectrometer and an endoscope with a light guiding means for the illumination of surfaces, wherein light is guided into the light guiding means at its proximal end and at its distal end the light is launched at the surfaces to be examined, wherein the distal end of the endoscope comprises a means for receiving the light reflected by the surfaces to be examined.
A device of this type is known in connection with an infrared (=IR) spectrometer from DE 197 32 215 A1, wherein reference is made to the said complete document.
With endoscopes of this type, scattered light is guided from interior surfaces of a body, mainly from blood vessels or cavities inside the body, via light guides to an external detector to the outside. Usually glass fiber bundles are used as light guides. As an alternative, also NIR transparent materials like silver hologenides or chalcogenides can be used. The intensity of the scattered light received and thus the signal intensity of the signal received is mainly proportional to the product of the cross-sections of the fibers, which guide the light from the spectrometer through the endoscope for recording, and of the cross sections of those fibers would receive the scattered light and guided outside to the detector.
A disadvantage of an endoscope of this type consists in that on the one hand the light directed to the surfaces to be examined, if. e.g. the inner vascular walls in a human body are to be examined, has to pass at first from the distal end of the light guiding means through the blood or other body fluids to the surface to be examined, and that the light reflected or scattered from there, has to penetrate the corresponding fluid again on its way back to the endoscope, said fluid normally being in motion, such that the local density may change with time. A further disadvantage consists also in that the distal end of the endoscope is not fixed, and thus shaking and a change of relative distances may happen during measurements, thus reducing the quality of the recorded optical spectra.
SUMMARY OF THE INVENTION
In contrast thereto, it is the object of the present invention to improve a device of the initially defined type in as simple as possible manner to obviate the above-mentioned disadvantages.
According to the invention, this object is achieved in a both simple and effective manner in that the distal end of the light guiding means is arranged within an inflatable balloon with an elastic exterior and that the light launched at the light guiding means and also the light reflected from the surfaces to be examined to the recording device penetrates in each case the exterior of the balloon.
Inflation of the balloon at the distal end of the light guiding means causes displacement of body fluids and of flowing blood and the exterior of the balloon abuts in a fixing manner in the area of the vascular inner wall to be examined such that the distal end of the endoscope does no longer change its relative distance from the surrounding wall of the vessel in the inflated state of the balloon. Thus, outer influences that change with time and might have a disadvantageous effect on the quality of the spectra are eliminated.
Inflatable balloon catheters as such are known in general, e.g. from “Pschyrembel Klinisches Wörterbuch”, Walter de Gruyter-Verlag, Berlin, N.Y., 1986, pages 170, 531, 622 and 1536. These known balloon catheters are, however, not used in connection with optical spectrometers. Their mechanical and optical construction is thus not suited to be used with a device according to the present invention.
One embodiment of the inventive device is preferred, wherein the elastic exterior comprises transparent sections in the area where the light enters and exits. In this way it is possible to optimize the elastic properties of the exterior of the balloon on the one hand and their optical properties in the area of the interesting surfaces on the other hand, independently of one another.
It is e.g. feasible to insert transparent “windows” in the corresponding sections of the exterior of the balloon. However, one embodiment is preferred in which the material of the elastic exterior is selected such that it is largely transparent in the spectral range of interest. In this manner, the light used for the spectroscopic examination may theoretically penetrate the exterior of the balloon unhindered at any point and it is not required to insert transparent sections under great efforts, but the exterior of the balloon can be produced of one piece.
In further embodiments of the invention, the elastic exterior of the balloon may preferably be formed of latex material which is known to be medically well compatible, has been tested for decades and is readily available. At least if the thickness of the exterior of the balloon is small, it is possible to achieve sufficient transparency in a large wave-length range.
In a particularly preferred manner, the balloon can be inflated with inert gas, preferably with helium. The path of rays in the direction of the surfaces to be examined and also away from the surfaces towards the detector extends in a chemically inert, optically highly transparent homogeneous medium.
In a particularly preferred embodiment of the device according to the invention, the elastic exterior of the balloon is constructed in such a manner that, in its inflated state, a cross-section of passage of a blood vessel to be examined remains open. In this manner, the passage of blood during vascular examinations can be maintained at least to a limited degree which may be vital with certain blood vessels.
In an advantageous further development of this embodiment, the exterior of the inflated balloon has at least one radial recess in its cross-section along the entire axial extent of the balloon which produces a cross-section of passage outside of the exterior of the balloon.
This further development is particularly easy to realize in that the exterior of the balloon in the area of the recess is formed of a thicker, reinforced and/or stiffened material. When the balloon is inflated, the exterior in this area will remain essentially rigid such that the desired recess will be formed there.
In an alternative further development, a continuous hollow channel extends along the axis of the endoscope through the elastic exterior of the balloon thus maintaining a defined and constant cross-section of passage through the balloon.
This is achieved in a particularly preferred manner by disposing the hollow channel on the axis of the endoscope and arranging the elements of the light guiding means, in particular optical fibers, in a circle around the hollow channel. This geometrical arrangement does not restrict the field of view of the endoscope. Despite the hollow channel it is possible to examine 360° of the surrounding surfaces in an annular view.
One embodiment of the device according to the invention is also advantageous in which the distal end of the light guiding means can be displaced relative to the exterior of the balloon, preferably in the direction of the longitudinal axis of the endoscope.
With a stationary endoscope, it is still possible to obtain recordings with longitudinal local dependency.
In a particularly preferred embodiment, the illuminated distal end of the light guiding means is provided with an ultrasound head which is rotatable preferably about the longitudinal axis of the endoscope. In this manner, critical locations, e.g. vascular constrictions can be pre-localized through ultra sound images and can subsequently be examined by an infrared spectroscope which images may serve e.g. for identifying the type of tissue or for analyzing depositions.
The light guiding means in embodiments of the i
Boese Matthias
Jaross Werner
Simon Arno
Bruker Optik GmbH
Lateef Marvin M.
Pass Barry
Vincent Paul
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