JP3552844B2 - Endoscope - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an endoscope for observing the inside of a living body, and more particularly, irradiates excitation light to a site inside the living body that absorbs a photosensitizer that emits fluorescence, and then emits light from the photosensitizer. The present invention relates to an endoscope that detects the intensity of fluorescent light to be emitted.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, endoscopes have been widely used for observing the inside of a living body and for treating while observing the inside of a living body. A current endoscope is a so-called electronic device including an illumination light irradiation system that irradiates illumination light to a site inside a living body via an optical fiber or the like, and an imaging unit that captures an image of the illumination light reflected at the site. Endoscopes are the mainstream.
[0003]
On the other hand, various studies have been made on a photodynamic diagnosis called PDD (Photodynamic Diagnosis). The PDD means that a photosensitizer having tumor affinity and emitting fluorescence when excited by light is previously absorbed in a tumor part of a living body, and the excitation light in the excitation wavelength region of the photosensitizer is applied to the part. Is irradiated to generate fluorescence, and the intensity of the fluorescence is measured, or an image based on the fluorescence is displayed to diagnose a tumor portion.
[0004]
For example, Japanese Patent Application Laid-Open No. 62-247232 discloses an endoscope for PDD which measures the above-mentioned fluorescence intensity. This endoscope basically includes, in addition to the illumination light irradiation system and the imaging means described above, an excitation light irradiation system that irradiates a site inside a living body with excitation light in an excitation wavelength region of a photosensitive substance. And a fluorescence detector for detecting the intensity of the fluorescence emitted from the site.
[0005]
[Problems to be solved by the invention]
However, this conventional endoscope for PDD is configured to irradiate excitation light over a wide area inside a living body and average the intensity of the fluorescence generated at that time, so that the localized tumor part is not affected. It is difficult to recognize and detect the strong fluorescence emitted from such a substance. In other words, fluorescent light that emits strongly from a very narrow part of a living body part and fluorescent light that emits weak light from a wide part may be detected in the same manner. If so, in the diagnosis based on the measured fluorescence intensity, there is a possibility that the localized tumor portion may be overlooked.
[0006]
Further, in the conventional endoscope for PDD, the above-described fluorescence and the normal image formed by the illumination light are guided to the fluorescence detector and the imaging unit by different optical systems, respectively. Even if the area is irradiated, it is difficult to accurately associate the captured normal image with the fluorescence generation position to specify the position. Further, in the conventional endoscope for PDD, since the excitation light irradiation system including the optical fiber and the fluorescence detection system are generally provided independently of each other, there is a possibility that a displacement occurs between the two systems. This also makes it difficult to accurately identify the position where the fluorescence is generated.
[0007]
If the location where the fluorescence is generated cannot be specified accurately, it will be impossible to correctly grasp the tumor part, and it will not be possible to correct the fluorescence intensity according to the distance from the excitation light irradiation system to the irradiation position. , The reliability of diagnosis decreases.
[0008]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an endoscope that can accurately specify and measure the light emission position of fluorescence from a small tumor portion or the like.
[0009]
[Means for Solving the Problems]
An endoscope according to the present invention has the following features.
An illumination light irradiating system that irradiates illumination light to a site inside a living body that absorbs a photosensitizer that emits fluorescence,
An excitation light irradiation system that irradiates the excitation light in the excitation wavelength region of the photosensitizer in a narrow range of the site, and irradiates the excitation light.
Illumination light reflected by the site and incident on the excitation light irradiation system, illumination light branching means for branching from the optical path of the excitation light,
Imaging means for capturing a normal image by the illumination light passing through the illumination light branching means;
Fluorescence emitted from the site and incident on the excitation light irradiation system, a fluorescence branching unit that branches from the optical path of the excitation light,
A fluorescence detector for detecting the intensity of the fluorescence that has passed through the fluorescence branching means.
[0010]
In the endoscope having the above configuration, more specifically, as described in claim 2,
An excitation light irradiation system has an optical fiber arranged in an introduction tube introduced into the living body, and an excitation light source that makes excitation light incident on the optical fiber from outside the living body,
Fluorescence branching means and a fluorescence detector are arranged outside the living body to receive the fluorescence emitted from the optical fiber,
Illumination light branching means and imaging means are disposed in the introduction tube.
[0011]
Further, the present invention is not limited to such a specific configuration. As described in claim 3, the excitation light irradiation system, the illumination light branching unit, the imaging unit, the fluorescence branching unit, and the fluorescence detector are introduced into a living body. It may be arranged in the introduction pipe.
[0012]
In the endoscope according to the present invention, as described in claim 4, an image display unit is provided which combines and displays a display indicating an area where fluorescence has been detected in the normal image picked up by the image pickup unit. Is desirable.
[0013]
Further, as the excitation light source constituting the excitation light irradiation system, it is desirable to use a wavelength variable light source as described in claim 5.
[0014]
Further, it is desirable that the fluorescence detector is combined with a fluorescence spectroscopy unit.
[0015]
【The invention's effect】
As described above, the endoscope of the present invention is configured so that the illumination light and the fluorescence that are both incident on the excitation light irradiation system are branched from the optical path of the excitation light and guided to the imaging unit and the fluorescence detector, respectively. The captured normal image and the fluorescence generation position can be accurately associated with each other. Further, in the endoscope of the present invention, since the excitation light irradiation system and the fluorescence detection system are partially shared, displacement of the two systems hardly occurs. From these two points, according to the endoscope of the present invention, it is possible to accurately specify the position where the fluorescence is generated in the captured normal image, and it is possible to prevent the localized tumor portion from being overlooked. You.
[0016]
Since the position where the fluorescence is generated can be accurately specified, the fluorescence intensity can be corrected according to the distance from the excitation light irradiation system to the irradiation position, and the reliability of diagnosis can be improved.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a side view of an endoscope according to a first embodiment of the present invention.
[0018]
The endoscope includes an illumination light source 10 that emits illumination light L1 that is white light, a condenser lens 11 that condenses the illumination light L1, and an optical fiber that is arranged so that the collected illumination light L1 enters. And a light guide 12 comprising: The light guide 12 is housed in a flexible introduction tube 14 introduced into the living body 13. In addition, the leading end of an optical fiber (single fiber) 15 is housed in the introduction pipe 14.
[0019]
An imaging lens 16 is provided at a position facing the tip of the optical fiber 15 (the left end in FIG. 1). Between the imaging lens 16 and the optical fiber 15, a concave lens 17 and a beam splitter 19 as an illumination light branching unit are arranged in this order from the optical fiber 15 side. A solid-state imaging device 20 such as a CCD imaging device is provided at a position where the light reflected by the beam splitter 19 is received. The solid-state imaging device 20 is connected to an image synthesizing unit 21, and the image synthesizing unit 21 is connected to an image display unit 22 including a CRT display device or the like.
[0020]
The rear end of the optical fiber 15 extends out of the introduction tube 14, and an excitation light source 30 that emits the excitation light L2 toward the rear end of the optical fiber is provided. Between the excitation light source 30 and the optical fiber 15, in order from the excitation light source 30 side, a dichroic mirror 31 that transmits the excitation light L 2 and reflects a fluorescent light L 3 described later, and converges the excitation light L 2 on the rear end of the optical fiber 15. A condensing lens 32 is provided.
[0021]
Fluorescent light L3 is emitted from the rear end of the optical fiber 15 as described later, and the fluorescent light L3 is reflected by a dichroic mirror 31 as fluorescent light branching means. At a position where the reflected fluorescence L3 is incident, a condenser lens 33 for condensing the fluorescence L3, an excitation light cut filter 34, and a fluorescence detector 35 for detecting the intensity of the fluorescence L3 are provided. The fluorescence detector 35 is connected to the image synthesizing unit 21.
[0022]
Hereinafter, the operation of the endoscope having the above configuration will be described. When observing the diagnostic site 45 inside the living body 13, the introduction tube 14 of the endoscope is introduced into the living body 13, and the illumination light L <b> 1 is emitted from the light guide 12 to the diagnostic site 45. The imaging lens 16 forms a normal image of the diagnostic site 45 by the illumination light L1 on the solid-state imaging device 20 via the beam splitter 19. The solid-state imaging device 20 captures this image and inputs an image signal S1 indicating the image to the image combining unit 21.
[0023]
The image synthesizing unit 21 performs an after-mentioned synthesizing process on the image signal S1 to create an image signal S3, and sends the image signal S3 to the image display unit 22. The image display means 22 displays an image based on the image signal S3. Therefore, the operator and the assistant can check the state of the diagnostic site 45 and the positional relationship between the introduction tube 14 and the diagnostic site 45 by observing the displayed image.
[0024]
Next, the fluorescence diagnosis will be described. The diagnostic site 45 is preliminarily absorbed with a photosensitizer that has tumor affinity and emits fluorescence when excited by light. Then, the diagnostic light 45 is irradiated with the excitation light L2 propagated through the optical fiber 15. After passing through the concave lens 17 and the beam splitter 19, the excitation light L2 is condensed by the imaging lens 16 and irradiates a very small portion on the diagnostic site 45. The illumination light source 10 and the excitation light source 30 are driven so as to emit the illumination light L1 and the excitation light L2, for example, alternately in a pulse shape.
[0025]
At the location of the diagnostic site 45 irradiated with the excitation light L2, the photosensitizer emits the fluorescence L3. The fluorescent light L3 is condensed by the imaging lens 16, passes through the beam splitter 19, is adjusted to the convergence position by the concave lens 17, is incident on the optical fiber 15, propagates through the optical fiber 15, and is guided out of the living body 13.
[0026]
The fluorescence L3 emitted from the rear end of the optical fiber 15 is reflected by the dichroic mirror 31, collected by the condenser lens 33, and received by the fluorescence detector 35. The excitation light L2 reflected at the diagnostic site 45 and traveling toward the fluorescence detector 35 is cut by the excitation light cut filter 34. The fluorescence detector 35 inputs a fluorescence intensity signal S2 indicating the intensity of the received fluorescence L3 to the image combining means 21. The image synthesizing means 21 synthesizes a signal indicating the fluorescence intensity indicated by the fluorescence intensity signal S2 by, for example, a numerical value with the image signal S1 to obtain the image signal S3 described above.
[0027]
Thus, an image displayed on the image display means 22 based on the image signal S3 is as shown in FIG. That is, the image display means 22 displays the normal image F of the diagnostic site 45 and the numerical value N indicating the intensity of the fluorescence L3. Here, since the photosensitizer has tumor affinity, when the above-mentioned numerical value N exceeds a predetermined value, it can be basically considered that the fluorescence L3 is generated from the tumor part.
[0028]
On the other hand, as shown in FIG. 1, the endoscope branches the illumination light L1 and the fluorescent light L3, which have both entered the excitation light irradiating system, from the optical path of the excitation light L2 to the solid-state imaging device 20 and the fluorescence detector 35, respectively. Since the light is guided, it is possible to accurately associate the captured normal image F with the position where the fluorescence L3 is generated. Therefore, for example, the center point of the normal image pickup range is set to the fluorescence detection position (excitation light irradiation position), and the center point of the normal image pickup range is aligned with the center of the screen of the image display means 22. If the mark M is displayed at the center of the screen as shown in 2, it can be specified that the portion overlapping the mark M in the normal image F is the fluorescence generation position.
[0029]
Therefore, when the numerical value N displayed on the image display means 22 exceeds a predetermined value, it can be determined that the portion of the normal image F overlapping the mark M is a tumor portion. Note that the size of the mark M is desirably the same size as the spot of the excitation light L2 on the diagnostic site 45 so that the fluorescence detection area can be more accurately grasped.
[0030]
On the other hand, it is more preferable to use a wavelength variable light source as the excitation light source 30 because it is possible to cope with various photosensitive materials having different excitation wavelengths.
[0031]
Further, it is also possible to combine the fluorescence detector 35 with fluorescence spectroscopy means and analyze the spectrum of the fluorescence L3 as conventionally performed. In that case, for example, a spectrum waveform may be displayed instead of the display of the numerical value N shown in FIG. Further, such a spectrum waveform and the above-mentioned numerical value N may be displayed on display means different from the image display means 22 for displaying a normal image.
[0032]
Next, an endoscope according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 3, the same elements as those in FIG. 1 are denoted by the same reference numerals, and a duplicate description thereof will be omitted.
[0033]
In the second embodiment, an excitation light source 30 composed of a semiconductor laser or the like is disposed in an introduction tube 14, and a dichroic mirror 31 as a fluorescence branching unit is provided between the excitation light source 30 and the beam splitter 19. And a concave lens 50 for adjusting the convergence position so that the fluorescence L3 converges on the light receiving surface of the fluorescence detector 35. Further, a fluorescence detector 35 for detecting the fluorescence L3 reflected by the dichroic mirror 31 and an excitation light cut filter 34 are also provided in the introduction tube 14.
[0034]
Also in the second embodiment, the imaging and display of the normal image of the diagnostic site 45 and the detection and display of the fluorescence intensity are performed in the same manner as in the first embodiment.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing an endoscope according to a first embodiment of the present invention. FIG. 2 is a schematic view showing a display state of a normal image and a fluorescence intensity in the endoscope of FIG. Schematic side view showing an endoscope according to a second embodiment of the present invention.
DESCRIPTION OF SYMBOLS 10 Illumination light source 11 Condensing lens 12 Light guide 13 Living body 14 Endoscope introduction tube 15 Optical fiber (single fiber)
Reference Signs List 16 imaging lens 17 concave lens 19 beam splitter 20 solid-state imaging device 21 image combining means 22 image display means 30 excitation light source 31 dichroic mirror 32 condenser lens 34 excitation light cut filter 35 fluorescence detector 45 diagnostic part 50 concave lens L1 illumination light L2 excitation Light L3 Fluorescence

Claims (6)

An illumination light irradiating system that irradiates illumination light to a site inside a living body that absorbs a photosensitizer that emits fluorescence,
An excitation light irradiation system that irradiates the excitation light in the excitation wavelength region of the photosensitizer in a narrow range of the site, and irradiates the excitation light.
Illumination light reflected by the site and incident on the excitation light irradiation system, illumination light branching means for branching from the optical path of the excitation light,
Imaging means for capturing a normal image by the illumination light passing through the illumination light branching means;
Fluorescence emitted from the site and incident on the excitation light irradiation system, fluorescence branching means for branching from the optical path of the excitation light,
An endoscope comprising: a fluorescence detector for detecting the intensity of the fluorescence having passed through the fluorescence branching means. The excitation light irradiating system has an optical fiber disposed in an introduction tube to be introduced into a living body, and an excitation light source that makes excitation light incident on the optical fiber from outside the living body,
The fluorescence branching means and the fluorescence detector are arranged outside the living body to receive the fluorescence emitted from the optical fiber,
The endoscope according to claim 1, wherein the illumination light branching unit and the imaging unit are disposed in the introduction tube. The said excitation light irradiation system, the illumination light branching means, the imaging means, the fluorescence branching means, and the fluorescence detector are arrange | positioned in the introduction pipe | tube introduce | transduced in the inside of the living body. Endoscope. 4. The image display device according to claim 1, further comprising: an image display unit that combines and displays a display indicating the area where the fluorescence is detected, in the normal image captured by the imaging unit. 5. Endoscope. The endoscope according to any one of claims 1 to 4, wherein a variable wavelength light source is used as an excitation light source constituting the excitation light irradiation system. The endoscope according to any one of claims 1 to 5, wherein a fluorescence spectroscopy unit is combined with the fluorescence detector.

Images