Patent Application
20050027163
The present invention relates to medical devices, and in particular to a catheter with imaging capabilities.
An endoscope is a type of catheter that has imaging capabilities so as to be able to provide images of an internal body cavity of a patient. Most minimally invasive surgical procedures performed in the GI tract or other internal body cavities are accomplished with the aid of an endoscope. A typical endoscope has an illumination channel and an imaging channel, both of which may be made of a bundle of optical fibers. The illumination channel is coupled to a light source to illuminate an internal body cavity of a patient, and the imaging channel transmits an image created by a lens at the distal end of the scope to a connected camera unit or display device.
As an alternative to an imaging channel made of a bundle of optical fibers, a semiconductor-type camera can also be attached onto the distal tip. One drawback of this alternative is that such cameras are relatively large in size, in comparison to the dimensions needed for certain surgical procedures. Another issue with either the semiconductor-type camera or the bundle of fibers, is that the ability to see a larger area requires moving the camera or the bundle of fibers. This type of movement is relatively complex to implement, and requires even more area. Furthermore, while endoscopes are a proven technology, they are relatively complex and expensive to manufacture.
Given these shortcomings, there is a need for a relatively small imaging device that is inexpensive and disposable.
To address these and other concerns, the present invention is a catheter that includes an imaging channel. The imaging channel may include an optical fiber bundle or a single optical fiber with a distal end and a proximal end. The field of vision of the imaging channel is increased by vibrating the distal end. A number of compact and relatively inexpensive technologies can be used to vibrate the distal end, such as electric coils, piezoelectric crystals, and microelectrical mechanical systems (MEMS). Other types of energy that can be used include ultrasound or frequency modulation.
In an embodiment utilizing an electrical coil, a metal-type ring or object encases the distal end and is contained in a housing with the electrical coil for vibrating the distal end in a controlled manner. This produces a scanning effect in that as the distal end moves, the field of vision at the distal end effectively increases. In alternate embodiments, the housing may contain other technologies for creating the movement, such as piezoelectric crystals, MEMS, etc. An objective lens or a series of lenses is placed in front of the distal end to magnify the image. A focusing screw mechanism is incorporated so that the image can be focused. At the proximal end, an imaging device such as a CCD, CMOS, pin hole, or photo diode camera is positioned so as to capture and transfer the image to either a processor or a computer that is able to store or display the image. A light processing box is located between the camera and the proximal end, which provides the source for the light that illuminates the imaged area.
It will be appreciated that the vision catheter of the present invention includes components that are widely available and that can easily be assembled. The simple design thus allows for the production of catheters that are relatively inexpensive and disposable and which have imaging capabilities while still remaining relatively small in diameter.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
The vision catheter 10 also includes a vibration generator 16. In accordance with the present invention, the vibration generator 16 vibrates the distal end 14 of the imaging cable 12. This essentially produces a scanning effect in that as the distal end 14 moves, the field of view that is sensed by the distal end 14 effectively increases. As will be described in more detail below with reference to
The imaging cable 12 also includes a proximal end that is received within a housing 20. The housing 20 also includes a light splitter (not shown) which receives light through a cable 25 from a light source 30. The cable 25 may include a group of standard clad optical fibers that function as illumination fibers for carrying the light from the light source 30 to the light splitter within the housing 20. The light from the light splitter within the housing 20 is provided through the one or more illumination fibers in the imaging cable 12 to the distal end 14 of the imaging cable 12 for illuminating the imaged area. The housing 20 also includes an aperture 22 through which the image signals from the proximal end of the imaging cable 12 can be received.
A series of objective lenses 52a and 52b are placed in front of the imaging cable 12 to focus and magnify the image. A focusing mechanism such as a screw (not shown) may be incorporated so that the image sensed by the imaging cable can be better focused. A housing 70 includes the housing 20 which receives the proximal end of the imaging cable 12. The housing 70 also includes an imaging device 72 which is positioned relative to the aperture 22 so as to capture and transfer the image signals from the proximal end of the imaging cable 12. The imaging device 72 may be a CCD, CMOS, pin hole, photodiode camera, or other type camera. The imaging device 72 transfers the image through a cable 75 to a processor 80. The processor 80 may store or display the image. When the image is to be displayed, the processor may provide image signals through a cable 85 to a monitor 90.
It will be appreciated that the present invention provides a vision catheter that is relatively easy to build and which can be made from widely available components. Prior vision systems, such as endoscopes, tended to be relatively complex and expensive. The vision catheter of the present invention is relatively inexpensive and disposable.
While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. For example, the imaging cable may incorporate the use of an optical single pixel or multi-fiber glass or plastic imaging bundle. The catheter construction could also include the optical bundle such that it is sandwiched or co-extruded and made to have any number of lumens. Extrusion technology can be used to provide any desired level of variable stiffness, torque, or articulation that is desired.
With regard to the illumination, while the casing at the proximal end of the imaging cable has generally been described as including a light splitter, it will be understood that any appropriate light directing mechanism may be utilized to focus light down to the tip at the distal end of the imaging cable so as to illuminate the imaged area. The light source itself could be replaced with a self-contained white light LED contained within the housing. The intensity of the light could be controlled by software or by a balancing control knob.
With regard to the field of view, focusing, and magnification, the lens or lenses at the distal end of the imaging fiber could be made to be adjustable so as to further increase the field of view or to allow for focus and additional magnification. The lens at the distal tip could be designed to have extra lumens for flushing so as to clean the surface. A focusing screw mechanism could be used to adjust the movement of the fiber for image sharpness and could be controlled by using any focusing technology known in the art. In addition, the vision catheter could be modified to include a mirror, either attached to the fiber or separated and appropriately positioned to allow for side viewing of images. By providing a side viewing port for the catheter, this would allow for a catheter with cutting wires to be observed during a surgical procedure.
Additional technologies that could be utilized for the vision catheter include infrared or ultrasound. It will be appreciated that these are just some of the various changes that could be made without departing from the spirit and scope of the invention. Accordingly, the embodiments of the invention, as set forth above, are intended to be illustrative, not limiting.
