JPH11244220A - Fluorescent endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent endoscope whose insertion tube end can make a sufficient approach to a part under observation without causing a situation of pick-up impossibility and further enable easy correction of received fluorescence intensity as well as simple exchange of an excited light cut-off filter. SOLUTION: A fluorescent endoscope, comprising: an insertion tube 10 which is to be inserted into a living body; a light-transmitting optical system consisting of a light guide 30 which is included in the insertion tube 10 to irradiate the inside of the living body with excited light L1, etc.; and a light receiving optical system consisting of an image pickup element which is included in the insertion tube 10 to receive fluorescent light generated at the living body in response to irradiation with the excited light L1, etc.; is further provided with a cap frame 20 consisting of a collar body 21 whose flat front end part 21a is located with a predetermined distance from the top of the insertion tube and whose rear end part 21b is detachably mounted on a top part of the insertion tube 10, and a filter 23 for blocking part of the excited light L1 which is going toward the light receiving optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluorescent endoscope,
More particularly, the present invention relates to a fluorescence endoscope in which a distal end portion of an insertion tube is sufficiently close to an observation site inside a living body so that a high-quality fluorescence image can be observed.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Application Publication No.
As shown in No. 2, an insertion tube inserted into the living body, a light transmitting optical system that is housed in the insertion tube and irradiates the living body with excitation light, and an irradiation tube that is housed in the insertion tube and emits the excitation light. 2. Description of the Related Art A fluorescence endoscope having a light receiving optical system that receives fluorescence generated from a living body upon reception is known.

[0003] As the above-mentioned fluorescence, there are auto-fluorescence emitted by the living body itself, and fluorescence by a drug previously contained in the observation site of the living body. By capturing and observing an image of such fluorescence or measuring its intensity, it becomes possible to specify, for example, a cancer infiltration range.

[0004] A part of the excitation light applied to the observation site of the living body may be reflected there and proceed toward the fluorescence receiving optical system. If such reflected excitation light is detected together with the fluorescence, a fluorescence image that does not accurately reflect the state of the observation site is captured, or the measurement of the fluorescence intensity is incorrectly performed. Therefore, in many cases, an excitation light cut filter is disposed in front of the fluorescence receiving optical system, and unnecessary excitation light is cut there.

[0005]

By the way, the fluorescence emitted from the living body as described above is usually extremely weak. In order to detect such fluorescence efficiently,
It is advantageous to bring the distal end of the insertion tube containing the light transmitting optical system and the light receiving optical system as close as possible to the observation site of the living body.

However, in the conventional fluorescent endoscope, when the distal end of the insertion tube is too close to the observation site, the excitation light irradiation range and the imaging range become extremely narrow and separated from each other, so that imaging becomes impossible. Was recognized.

In the case where the invasion range of the cancer is specified based on the fluorescence intensity as described above, the received fluorescence intensity is corrected according to the distance between the tip of the insertion tube and the observation site and the illuminance of the excitation light. However, since it is difficult to measure the distance with a conventional fluorescent endoscope, it is very troublesome to perform this correction.

On the other hand, since the wavelength of the fluorescent light varies depending on the part of the living body and the medicine used, the above-described excitation light cut filter often needs to be replaced according to the part of the living body and the medicine used. In a conventional fluorescence endoscope, replacement of the excitation light cut filter has been troublesome.

The present invention has been made in view of the above circumstances, and can always bring the distal end of an insertion tube sufficiently close to an observation site without causing a situation in which imaging is impossible.
It is an object of the present invention to provide a fluorescence endoscope that can easily correct the intensity of received fluorescence and replace the excitation light cut filter.

[0010]

According to the present invention, there is provided a fluorescent endoscope having an insertion tube, a light transmitting optical system, and a fluorescent light receiving optical system as described above. The frame is located at a predetermined distance from the distal end of the insertion tube, and the rear end is detachably assembled to the distal end of the insertion tube, and the excitation is fixed to the frame and is directed toward the light receiving optical system. It is characterized by having a cap frame comprising a filter for cutting light.

Preferably, in this fluorescent endoscope,
The frame has a cylindrical peripheral portion, and a portion located inside thereof for holding the filter, and a front end of the peripheral portion serving as a front end of the frame is forward of a portion holding the filter. It is configured to protrude into.

On the other hand, a cylindrical excitation light absorber extending in the thickness direction and absorbing the excitation light is preferably disposed around the excitation light cut filter.

[0013]

In the fluorescent endoscope of the present invention, the flat front end is located at a predetermined distance from the distal end of the insertion tube, and the rear end is detachably assembled to the distal end of the insertion tube. By providing the cap frame having the frame to be inserted, when the insertion tube is lightly pressed against the observation site, the flat front end of the frame pushes the observation site flat.

In this state, the distance from the distal end of the insertion tube to the front end of the frame, that is, the observation site, is always kept at a predetermined distance. Therefore, if the shape of the frame is set so that the above-mentioned predetermined distance is an appropriate value, the tip of the insertion tube is always brought into contact with the observation region without causing the tip of the insertion tube to be too close to the observation site. It becomes possible to bring it close enough to the observation site.

[0015] If the observation region is pushed and spread in a flat state, it is possible to clearly image the observation region.

If the tip of the insertion tube can be brought sufficiently close to the observation site as described above, the power of the excitation light can be reduced.

If the distance from the distal end of the insertion tube to the observation site is always kept at a predetermined distance, there is no need to actually measure this distance, so that the correction of the intensity of the received fluorescent light is very simple.

Further, since the excitation light cut filter is fixed to the frame, if the excitation light cut filter needs to be replaced, the frame is removed from the distal end of the insertion tube and another excitation light cut filter is removed. What is necessary is just to attach the frame to which the cut filter is fixed to the distal end of the insertion tube, and the work of replacing the filter is extremely facilitated.

In the case where a cylindrical excitation light absorber extending in the thickness direction of the excitation light cut filter and absorbing the excitation light is arranged around the excitation light cut filter, the excitation light cut filter is placed before reaching the observation site. Excitation light that attempts to enter the filter from the peripheral end side due to multiple reflection at the periphery or the like can be absorbed and cut here.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a main part of a fluorescent endoscope according to an embodiment of the present invention, and FIG. 2 shows an overall shape of the fluorescent endoscope. As shown in FIG. 2, the fluorescent endoscope includes an insertion tube 10 inserted into a living body.
An operating unit 11 connected to the rear end of the insertion tube 10, a universal cord 12 extending from the operating unit 11, a light source and a control unit 13 connected to the universal cord 12, And a monitor device 14 electrically connected to the control unit 13.

The insertion tube 10 includes a hard distal end portion 15, a bendable bending portion 16, and a soft portion 17 in this order from the distal end side. A cap frame 20 is detachably fitted to the distal end portion 15.

As shown in FIG. 1, in the insertion tube 10, a light guide 30 for propagating, for example, excitation light L1 in a blue-violet region emitted from an excitation light source (not shown) in the light source and the control unit 13 is provided. An illumination lens 31 disposed close to the tip of the light guide 30 is housed.

Further, in the insertion tube 10, the fluorescent light L emitted from the observation site 32 in the living body upon receiving the irradiation of the excitation light L1 is received.
An objective lens 33 for condensing the light, a CCD image sensor such as a CCD image sensor arranged behind the objective lens 33, a signal line 35 connected to the image sensor 34 and extending to the light source and the control unit 13. Is stored.

As shown in FIG. 1, the cap frame 20 has a flat front end 21a located at a predetermined distance from the front end 10a of the insertion tube 10, and a rear end 21b is connected to the front end of the insertion tube. A frame 21 is detachably fitted to the frame 15 and a filter block 22 is fixed to the frame 21.

As shown in detail in the front view of FIG. 3, the filter block 22 cuts the excitation light L1 while transmitting the fluorescence L2, and an excitation light cut filter 23, into which a transparent member is fitted so that the excitation light L1 is inserted. Excitation light window 24 to be transmitted
In addition, an illumination light window 25 in which a transparent member is fitted, which transmits illumination light transmitted by a light transmission optical system (not shown), and a through hole 26 as a forceps hole are provided.

Hereinafter, the operation of the fluorescent endoscope having the above configuration will be described. When capturing a fluorescent image of the observation site 32 in the living body, the insertion tube 10 is inserted into the living body after the cap frame 20 is fitted to the distal end portion 15. And this insertion tube 10
For example, when lightly pressed against the observation site 32 side, such as the inner wall of the digestive organ, the flat front end 21a of the frame 21 of the cap frame 20 is moved to the observation site 32.
It comes into contact with 32 and pushes it to a flat state (state in FIG. 1).

Further, the excitation light source in the light source and the control unit 13 is driven, and the excitation light L1 emitted therefrom propagates through the light guide 30, and is irradiated on the observation site 32 through the illumination lens 31 and the excitation light window 24. You. The observation site 32 irradiated with the excitation light L1 emits fluorescence L2 (autofluorescence or fluorescence from a drug previously contained in the observation site 32). Since the fluorescent light L2 is condensed by the objective lens 33 and enters the image pickup device 34, the image of the observation site 32 by the fluorescent light L2 is picked up by the image pickup device 34.

An image signal indicating this fluorescent image is input to the light source and control unit 13 of FIG. 2 through a signal line 35, where it is subjected to appropriate processing and then sent to the monitor device 14,
Used for displaying fluorescent images.

The light source and control unit 13 is provided with an illumination light source that emits illumination light that is white light, and the illumination light is transmitted through an optical system similar to the light guide 30 and the illumination lens 31 to the observation site 32. Can be irradiated. Then, an image (normal image) of the observation site 32 is captured by the illumination light and can be reproduced on the monitor device 14. The means relating to the normal image imaging is described with reference to the illumination light window shown in FIG.
Illustrations other than 25 are omitted.

As described above, when the observation region 32 is pushed and expanded at the front end 21a of the frame to capture a fluorescent image, the distance from the insertion tube tip 10a to the observation region 32 is naturally kept at a predetermined distance. Therefore, the frame 21 is set so that the predetermined distance has an appropriate value.
If the shape of the insertion tube is set, the insertion tube tip 10a is positioned at the observation site 32.
The leading end 10a can always be sufficiently brought close to the observation region 32 without causing a situation in which imaging is impossible due to being too close to.

If the distance from the insertion tube tip 10a to the observation site 32 is always kept at a predetermined distance, there is no need to actually measure this distance, so that the above-described correction of the received light fluorescence intensity becomes very simple. .

Although part of the excitation light L1 is reflected at the observation site 32, the reflected excitation light L1 traveling toward the image sensor 34 is cut by the excitation light cut filter 23.

This prevents the reflected excitation light L1 from adversely affecting the imaging of the fluorescent image.

The wavelength of the fluorescent light L2 generated from the observation site 32 differs depending on the site and the medicine, and it is necessary to replace the excitation light cut filter 23 according to the wavelength.
In the present apparatus, when replacement of the excitation light cut filter 23 is required, the frame 21 is removed from the distal end portion 15 of the insertion tube 10, and the frame 21 to which another excitation light cut filter is fixed.
Can be attached to the insertion tube distal end portion 15, so that the work of replacing the filter is extremely facilitated.

Further, if the observation site 32 is expanded and flattened by the action of the frame 21, the observation site 32 can be clearly imaged.

If the distal end of the insertion tube 10 can be brought sufficiently close to the observation site 32 as described above, the power of the excitation light L1 can be reduced. More specifically, the distance between the insertion tube tip 10a and the observation site 32 can be set to 1/5 to 1/10 of the conventionally set distance.
By doing so, the power of the pumping light L1, which conventionally required about 100 mW, can be reduced to about several mW. The distance is, for example, 10 mm in diameter of the insertion tube 10.
In the case of about mm, it becomes 5 to 10 mm.

If the power of the excitation light is as low as the above, a semiconductor laser that emits a blue-violet laser beam with a wavelength of 403 nm, for example, can be used as the excitation light source. In the case of autofluorescence, the use of such a semiconductor laser can be said to be particularly preferable because the excitation efficiency is good at a wavelength of about 400 to 410 nm.

When the power of the excitation light is as low as above, most of the optical system for transmitting the illumination light for capturing the normal image and the optical system for transmitting the excitation light are used in common. The optical path can be switched by a movable mirror or the like between the time of imaging and the light transmission optical system can be significantly simplified.

In the above embodiment, the front end 21a of the cylindrical portion of the frame 21 has a shape protruding forward from the filter block 22, but the front end of the frame 21 is The frame 21 may be formed in a U-shaped cross section so as to be flush with the front surface.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a cap frame 40 used in another embodiment of the present invention. The cap frame 40 has a cylindrical excitation light absorber 41 extending around the excitation light cut filter 23 in the thickness direction and absorbing the excitation light, as compared with the cap frame 20 used in the above-described embodiment. Is different.

When such an excitation light absorber 41 is provided, the light is multiply reflected at the periphery of the filter 23, for example, at both end surfaces of the excitation light window 24 before reaching the observation site, so that the periphery of the filter 23 is removed. Excitation light to be incident from the end side can be absorbed and cut here.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing a fluorescent endoscope according to an embodiment of the present invention.

FIG. 2 is a side view showing the overall shape of the fluorescent endoscope in FIG. 1;

FIG. 3 is a front view showing a cap frame used in the fluorescent endoscope in FIG. 1;

FIG. 4 is a front view showing a cap frame used in another embodiment of the present invention.

[Explanation of symbols]

 10 Insertion tube 10a Insertion tube tip 12 Universal cord 13 Light source and control unit 14 Monitoring device 15 Insertion tube tip 16 Insertion tube bending portion 17 Insertion tube flexible portion 20 Cap frame 21 Frame 21a Front end 21b Frame Back end of body 22 Filter block 23 Excitation light cut filter 24 Excitation light window 25 Illumination light window 30 Light guide 31 Illumination lens 32 Observation site 33 Objective lens 34 Image sensor 35 Signal line 40 Cap frame 41 Excitation light absorber L1 Excitation light L2 fluorescence

Claims (3)

[Claims] 1. An insertion tube inserted into a living body, a light transmitting optical system housed in the insertion tube for irradiating excitation light to the inside of a living body, and a light receiving optical system housed in the insertion tube and receiving the excitation light. A fluorescence endoscope having a light receiving optical system for receiving fluorescence generated from a living body, wherein a flat front end is located at a predetermined distance from a front end of the insertion tube, and a rear end portion of the insertion tube is A fluorescence endoscope comprising: a frame frame detachably assembled to a distal end portion; and a cap frame fixed to the frame frame, the filter frame cutting an excitation light toward the light receiving optical system. 2. The frame has a cylindrical peripheral part and a part located inside the cylindrical part for holding the filter, and the front end of the peripheral part, which is the front end of the frame, holds the filter. The fluorescent endoscope according to claim 1, wherein the endoscope protrudes forward from a holding portion. 3. The fluorescent light-emitting device according to claim 1, wherein a cylindrical excitation light absorber extending in a thickness direction of the filter and absorbing the excitation light is arranged around the filter. Endoscope.