JPS61159936A - Spectral image pick-up apparatus of biological tissue - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a spectral image capturing device for biological tissue, and in particular, a method for capturing spectral images of biological tissue such as a human body without contacting the biological tissue. This invention relates to a spectroscopic imaging device for biological tissue that can be used to capture images.

(Prior art) As is well known, when a biological tissue is irradiated with excitation light such as a laser beam, fluorescent light with a unique wavelength versus intensity distribution determined depending on the region and state of the tissue is emitted from the irradiated region. That is, each part of biological tissue has unique fluorescent wavelength distribution characteristics.

Based on the fact that biological tissues have the unique fluorescence wavelength distribution characteristics described above, the present inventor has developed a number of biological tissue diagnostic devices, image analysis devices, etc. that utilize these characteristics, and has already applied for patents. .

Among the above patent applications, for example, Japanese Patent Application Laid-Open No. 59-13923
Specification No. 7 states that only a specific wavelength component of the fluorescent light generated by excitation light irradiation is extracted using a filter, an image of that specific wavelength is photographed, and each image has a different density depending on its density difference. A fluorescence spectroscopic image analysis device is described that assigns color tones and obtains a single pseudocolor image.

Furthermore, Japanese Patent Application No. 59-102080 discloses that by taking fluorescence spectroscopic images of at least two types of specific wavelengths and obtaining intensity differences between corresponding portions of each of the images, An optical imaging device for biological tissue is described that captures an image with enhanced contrast by obtaining a difference image.

In general, Japanese Patent Application No. 59-154038 discloses that fluorescent light or reflected light generated by excitation light irradiation is split into multiple wavelengths, and an image of a biological tissue is photographed using each wavelength of light. The distribution pattern of fluorescent light intensity or reflected light intensity in each part of the biological tissue is recognized from the eight images of the biological tissue, and the display color of the image part corresponding to each part of the biological tissue is determined according to the shape of each distribution pattern. Further, a spectral pattern image display device for a biological tissue is described that reconstructs an image of the biological tissue as a pseudo-color image by determining the brightness (or intensity) of the color based on the area of the distribution pattern.

Now, when obtaining a pseudo-color image or a difference image from one spectral image or multiple spectral images at different wavelengths, it is natural that the image intensity in the healthy area of each spectral image is must be constantly adjusted so that it remains relatively constant.

That is, for example, if you take a spectral image at a specific wavelength and assign a different color tone to each density difference in that image to obtain a pseudocolor image, you can use different It is difficult to compare pseudo-color images created based on spectral images taken at different wavelengths unless the color tone of the healthy part of the biological tissue is the same.

In addition, the difference image created from spectral images taken with at least two types of wavelengths can be created by making the intensity of each spectral image constant in the healthy area, thereby comparing the relative intensity difference between the healthy area and the abnormal area. It can be a big deal.

Furthermore, if there is a risk of optical changes occurring over time in the optical system that connects the light source or the subject to the camera, even if the spectral image is taken only at the same wavelength, the biological It is necessary to adjust the image intensity of the healthy part of the tissue to a constant value.

For this reason, conventionally, when taking fluorescence spectroscopic images, a standard fluorescence scale was placed on the biological tissue to be photographed, and the fluorescence generated by the standard scale was made to be the same on the imaging plane of the camera. The density of each spectral image is adjusted so that the intensity is as follows.

Furthermore, similar adjustments need to be made not only when capturing a fluorescent spectroscopic image but also when capturing a reflected light spectroscopic image when making a diagnosis using the absorbance characteristics of a biological tissue.

(Problems to be Solved by the Invention) The above-described conventional techniques had the following problems.

That is, fluorescence spectroscopic imaging of biological tissues is extremely important for diagnosis of biological tissues, but as mentioned above, conventionally, each time a spectral image R shadow is captured, a fluorescent standard is placed on the biological tissue that is the subject. Since a scale had to be mounted, (1) taking spectroscopic images was extremely troublesome;

(2) Spectroscopic images can only be taken on tissues excised from living organisms. In other words, since it is not possible to take spectroscopic images without contacting biological tissue, it is virtually impossible to take spectroscopic images of tissues within the body cavity of a living body using an endoscope or the like. It is.

(3) Since the effective area of each spectral image is reduced, it is not possible to efficiently display the test area in the image output by the image recording device.

The present invention has been made to solve the above-mentioned problems.

(Means and Effects for Solving the Problems) In order to solve the above problems, the present invention provides that fluorescent light generated by biological tissues or reflected light reflected from biological tissues is transmitted to each spectral image capturing camera. Since we have taken measures to measure the intensity of a portion of the light after it has been branched towards and passed through a band-pass filter, the light intensity measurement can be performed to detect fluorescence generated by normal parts of biological tissue or normal parts. By arranging the spectral image copying device in a manner similar to that used for reflected light reflected at , is characterized in that it has the advantage of being able to easily and accurately compare and analyze multiple spectral images without using a standard scale.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic block diagram of a first embodiment of the invention.

In FIG. 1, a laser beam 20 emitted from a laser light source 10 passes through a collimator 11 and becomes a parallel beam. Then, the laser beam 20 is transmitted to the vibrating diffuser plate 1
After passing through 2 and polarizing filter 13A, most of the light is reflected by first dichroic mirror 14A, and is irradiated onto test portion 15-A of biological tissue 15.

The vibrating diffuser plate 12 is connected to a vibrating plate (not shown) and can vibrate in a direction parallel to the surface of the vibrating diffuser plate 12 (in the direction of arrow B). By photographing the vibrating diffuser plate 12, it is possible to uniformly irradiate the sample with laser light.

The angle between the surface of the first dichroic mirror 14A and the laser beam 20 incident on the surface is about 60.
In other words, if the laser beam 20 travels horizontally, it is arranged to form an angle of about 30 degrees with the vertical line.

The test portion 15A is irradiated with the laser beam 20 and generates fluorescent light. The fluorescent light travels, for example, in the direction of arrow 30A together with the reflected light component of laser light 20. Most of the reflected light component of the laser beam 20 is reflected by the first dichroic mirror 14A, but a part of it passes through the first dichroic mirror 14A together with fluorescent light.

Note that by arranging the dichroic mirror 14A as described above, the reflected light component of the laser beam 20 can be removed more effectively.

The light that has passed through the first dichroic mirror 14A travels in the direction of the arrow 30B, and then roughly passes through the polarizing filter 1381, the second dichroic mirror 1481, and the interference filter 16. The polarizing filter 13B is arranged so as not to pass the reflected light component of the laser beam 20 polarized by the polarizing filter 13A.

The light passing through the interference filter 16 is passed through a half mirror.
61, 62 and 63 as shown in the figure, passing through a bandpass filter 5" 1.52 and a Taref 1-type filter 53.54, and photometric fibers 91-94, respectively, to an image intensifier 21. , 22° 23 and 24.

The bandpass filter 51 can pass light having a wavelength λr of the laser light 20 (for example, about 514.5 nllll if the laser light is an argon laser). Further, the bandpass filter 52 can pass light having a wavelength λp (for example, about 700 nm) in the infrared region.

The turret filters 53 and 54 have a structure as shown in FIG. 2, for example. That is, the turret type filter 53, 54 has a disc-shaped frame 18A.
Band-pass filters 18 of various different wavelengths are provided in the filter and can be rotated about a central axis 18B.

FIG. 3 is a schematic perspective view of the photometric fibers 91 to 94.

In FIG. 3, photometric fibers 91 to 94 are constituted by a plurality of optical fibers 93A to 93D1 and a frame 90 that holds the optical fibers. Although four optical fibers are shown in the figure, there may be three or less, or five or more optical fibers. Also, the arrow is
FIG. 1 shows the traveling direction of light that has passed through or been reflected by each half mirror.

The optical fibers 93A to 93D are supported by a frame 90 so that light from the biological tissue 15 enters the light receiving portions 91A to 91D of the optical fibers.

That is, as shown in FIG. 4, assuming that the excitation light irradiation area of the biological tissue 15 is the part indicated by the reference numeral 15E,
Light receiving sections 91A to 9 of each of the optical fibers 93A to 93D
1D, tissues 95A to 9 in the excitation light irradiation region 15E
Each of the optical fibers 9 is arranged so that the light from 5D enters
3A to 93D are arranged.

In addition, in order to prevent the photometric fibers 91 to 94 from appearing in the spectral images taken by each camera, a portion corresponding to the imaging area 15F of the biological tissue 15 corresponding to the spectral image and the excitation light irradiation area 15E is provided. It is desirable that each photometric fiber be placed at

Returning to FIG. 1 again, the ends 92A to 92D (FIG. 3) of each of the optical fibers 93A to 93D are connected to phototubes (not shown) in the image processing device 71. The phototube measures the intensity of light incident on each optical fiber.

Then, using the measured light intensity of each optical fiber, the average value of the light intensity is calculated for each photometric fiber.

The image intensifiers 21, 22, 23, and 24 each have a relay lens 31, 32, 33, . and 34, cameras 41° 42.436 and 44
It is connected to the. The cameras 41, 42, 43, 44
is, for example, a camera that uses an image sensor such as a COD as its light receiving element. The cameras 41, 42, 4
3° 44 is connected to the image processing device 71. Similarly, an image recording device 81 is also connected to the image processing device 71.

Note that the apparatus is configured such that at least the optical path from the dichroic mirror 14A to each image intensifier passes through the inside of the dark box 100. In FIG. 1, a part of the dark box 100 is omitted.

Now, the fluorescent light generated in the test portion 15A passes through the first dichroic mirror, the polarizing filter, the second dichroic mirror, the interference filter, the half mirror 1, and the bandpass filter, and reaches each image intensifier. However, when passing through each optical element, a portion of the fluorescent light may be reflected or absorbed depending on the characteristics of the optical element, resulting in attenuation.

Therefore, before taking a spectral image with each of the cameras,
By irradiating each of the optical elements with light of various wavelengths and measuring the attenuation rate, a more accurate spectral image can be obtained.

Now, in the first embodiment of the present invention having the above configuration, first, the image intensifiers 23 and 24
The turret filters 53 and 54 are rotated to select a band-pass filter so that fluorescent light in a desired wavelength band is incident on the filter.

At this time, when the biological tissue 15 has a fluorescence wavelength distribution characteristic as shown in FIG. 5, and roughly diagnoses whether the test portion 15A of the biological tissue R15 is normal or cancerous, For example, band pass filters having wavelengths λ2 and λ3 are disposed on the optical path of the fluorescent light incident on the image intensifiers 23 and 24.

Next, the state of the test portion 15A of the biological tissue 15, that is, which part of the test portion 15A has the lesion, is roughly diagnosed by visual inspection, and the lesion portion 15C (the fourth
The image diagnostic apparatus is arranged so that the image shown in FIG.

Tissues 95A to 95D of the normal region 15D (Fig. 4)
The fluorescent light generated is incident on each of the photometric fibers 91 to 94, its light intensity is measured, and its average value is calculated.

In this way, if the light intensity (average value) of the normal area 15D in each spectral image is measured, even if the light intensity of the normal area 15D differs for each spectral image, the density of each spectral image can be calculated.
Each of the light intensities can be adjusted to an optimal value.

Fluorescence spectroscopic images at wavelengths λ2 and λ3 are amplified by the image intensifier 23.24 and then photographed by the camera 43.44. The fluorescence spectroscopic images photographed by the cameras 43 and 44 contain some laser light components of wavelength λr, despite the arrangement of the dichroic mirror, polarizing filter, bandpass filter, etc.

Wavelength λr incident on image intensifier 21
A spectral image produced by the laser beam is amplified by the image intensifier 21 and imaged by the camera 41. Similarly, a fluorescence spectroscopic image of wavelength λp incident on the image intensifier 22 is amplified by the image intensifier 22 and photographed by the camera 42.

Each of the spectral images taken by the cameras 41 to 44 is sent to an image processing device 71, where the following processing is performed.

First, the wavelengths λ2 and λ taken by cameras 43 and 44 are
As mentioned above, the fluorescence spectroscopic image according to No. 3 contains an acid component having the wavelength λr of the laser beam.

Therefore, the wavelength λr acid component is removed by electrically subtracting the spectral image taken by the camera 41 from each of the fluorescence spectral images.

At this time, since the intensity of the laser beam of wavelength λr incident on the camera 41 is different from the intensity of the laser beam of wavelength λ'' incident on the camera 43.44, the intensity of the laser beam incident on the camera 41, 43.44 is different.
Each image must be corrected so that the laser light intensities at wavelength λr in the images taken are equal to each other.

The above correction is performed by calibrating using a fluorescence standard scale etc. before capturing the fluorescence spectroscopic image.
It can be done easily. That is, for example, the correction can be made by comparing the laser beams 20 reflected by the fluorescent standard scale in advance.

If the laser light intensity in each image taken by the cameras 41, 43.44 becomes equal, the camera 43.44
The fluorescence spectroscopic image taken by the camera 4 is temporarily stored in an image memory in the image processing device 71, and then, based on the light intensity of each pixel in the memory, the camera 4
By subtracting the light intensity of each pixel of the image photographed in step 1, the laser light component can be completely removed from the fluorescence spectroscopic images photographed by the cameras 43 and 44. This results in
The contrast of the fluorescence spectroscopic image can be made clear.

Next, using the fluorescence spectroscopic image photographed by the camera 42, the wavelength λ2 from which the laser light component has been removed is determined. The fluorescence component of wavelength λp is removed from the fluorescence spectroscopic image of λ3. The fluorescence component having the wavelength λp can also be removed in the same manner as the laser light component.

By removing the fluorescent component of the wavelength λp, the fluorescent spectroscopic image is free from glitter caused by the unevenness of the biological tissue.

Then, the intensities of the spectral images taken by the cameras 43 and 44 are adjusted so that the intensities of the fluorescent light generated from the tissue of the normal region measured by each photometric fiber are equal.

Thereafter, a difference image can be created by obtaining the intensity difference of each part of each image.

Further, in this case, the difference image has a clearer contrast than the difference image created by the conventional method, and it is possible to prevent roughness and glitter on the surface of the test area 15A, so that the biological tissue can be diagnosed. can be done reliably.

The difference image is visualized by the image recording device 81 and output as a hard copy.

Note that the difference image may be created not only by two fluorescence spectroscopic images taken at different wavelengths, but also by three or more fluorescence spectroscopic images.

The measurement fiber may also be placed between each camera and an image intensifier.

FIG. 6 is a schematic block diagram of a second embodiment of the invention. In FIG. 6, the same reference numerals as in FIG. 1 refer to the same or equivalent parts, so a description thereof will be omitted.

A second embodiment of the present invention is an application of the fluorescence spectral image difference image creation apparatus described in the first embodiment to an endoscope. In addition, in FIG. 6, in order to remove the laser beam component with the wavelength λr and the fluorescent component with the wavelength λp− included in the spectral image, the image tensifiers 21 and 22 arranged in the first embodiment are used. , cameras 41, 42, etc. are omitted.

In FIG. 6, a laser beam 20 emitted 9A from a laser light source 10 is transmitted through a collimator 11 and a vibrating diffuser plate 12.
, and the polarizing filter 13A, it is reflected by the first dichroic mirror 14A.

The reflected laser beam 20 is incident on one end of the optical fiber bundle 200 and is emitted from the other end of the optical fiber bundle 200.

Therefore, by inserting the other end of the optical fiber bundle 200 into the stomach S of a living body, for example, a desired inner wall (tested portion) of the stomach S can be irradiated with the laser beam 20.

The optical fiber bundle 200 is inserted into the stomach S in such a way that the part that is considered to be a diseased part of the subject is placed in the center of each spectral image, and the part that is considered to be a diseased part of the subject is placed in the center of the normal part of the subject. This is done so that the fluorescence generated from the desired portion is incident on the optical fiber bundle 200.

The fluorescent light generated from the inspection area by the irradiation passes through the optical fiber bundle 200 again, passes through the first dichroic mirror 14, passes through a predetermined optical element, and enters the camera 43, 44. , a spectral image is taken.

Each of the spectral images is adjusted to an optimal density by the image processing device 7'lA based on the average value of the fluorescence intensity generated from the normal part of the test site, which is measured by the photometric fiber 93.94. Ru.

After that, a difference image is created from each spectral image.

The created difference image is displayed on the cathode ray tube 82.

In this way, in the present invention, there is no need to bring the standard scale into contact with the test area when taking a spectroscopic image, so as explained in this second embodiment, the irradiation of excitation light and the capture of fluorescent light can be controlled. The optical fiber bundle 200 can be used to imitate a fluorescence spectroscopic image inside the body cavity of a living body.

As mentioned above, in FIG. 6, the spectral image capturing means and the wavelength λr are
Although the spectral image photographing means is omitted due to the fluorescent wavelength of p, it goes without saying that each of the above-mentioned means may be arranged within the eye-catching device as explained in FIG.

Furthermore, even if there is only one camera, a difference image can be created by sequentially capturing fluorescence spectroscopic images by replacing the filters arranged on the incident surface of the image intensifier.

Now, as is clear from the above description, the basic technical idea of the present invention is to measure the image intensity in a specific region (normal portion) of a photographed spectral image using a photometric fiber. Therefore, any image processing may be performed on the photographed fluorescence spectroscopic image.

That is, in the first and second embodiments, a difference image is created using a plurality of the fluorescence spectroscopic images.
The present invention is not particularly limited to this, and for example, a pseudo color image may be created by using a plurality of the fluorescence spectral images and a pattern obtained from the fluorescence intensity of each corresponding part, or A pseudo-color image may be created by applying a different color tone to each density difference in the fluorescence spectral image.

Furthermore, various types of fluorescence intensity patterns are stored in the image processing device according to the lesions of the test site and their progress, and these patterns and patterns obtained from the fluorescence intensity of each part of each fluorescence spectroscopic image are stored in the image processing device. The spectroscopic imaging device for the biological tissue may be configured to compare the patterns, and when each pattern matches, display the type and progress state of the lesion in the corresponding area.

In this case, if the above-mentioned processing is sequentially performed on a plurality of fluorescence intensity patterns stored in the image processing device according to a preset program, the diagnosis of the region to be examined can be performed easily and in a short time. We can do it at home.

Furthermore, although each of the above embodiments describes a case where the present invention is applied to an apparatus that takes a fluorescence spectroscopic image, the present invention is not particularly limited to this, and the present invention is applied to an apparatus that takes a reflected light spectroscopic image. may be applied to.

Furthermore, even if fluorescence spectroscopic images are simply taken at different wavelengths, each fluorescence spectroscopic image can be displayed with constant fluorescence intensity in the normal area, making it possible to diagnose tissues. can be done reliably.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

In other words, it is possible to detect the light intensity that serves as a reference for each spectral image without contacting the biological tissue. (1) The time required for diagnosing biological tissue can be shortened; It can be done efficiently.

(2) Even if a spectral image is imitated using an endoscope or the like for tissue in the body cavity of a living body, it is possible to accurately compare multiple spectral images or perform image analysis using the spectral image. Therefore, diagnosis of cancer, etc. can be easily and reliably performed. −

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of the first embodiment of the present invention;
The figure is a schematic plan view of the turret type filter, Figure 3 is a schematic perspective view of the photometric fiber, Figure 4 is a plane view showing the excitation light irradiation area of the test area, Figure 5 is the fluorescence generated by biological tissue, FIG. 6 is a schematic block diagram of a second embodiment of the present invention. 10... Laser light source, 11... Collimator, 1
4A...first dichroic mirror, 14B...
Second dichroic mirror, 15... Biological coarse fabric, 1
5A...Test part, 16...Interference filter, 18
．． 51, 52... Bandpass filter, 20... Laser light, 21-24... Image intensifier, 41-44... Camera, 53.54... Turret type filter, 71.71A. ...Image processing device,
81... Image recording device, 82... Braun tube, 90
...Frame, 91-94...Photometric fiber, 93A
~93D...Optical fiber, 200...Optical fiber bundle agent Patent attorney Michito Hiraki 1 other person Figure 1 whistle 2 A Figure 5 person r person 1 person t entry
λp gL+Figure 4Figure 6

Claims (3)

[Claims] (1) A light source that irradiates light onto biological tissue, a spectroscopic means that spectrally spectra either the fluorescence generated from the biological tissue by the irradiation of the light or the reflected light reflected by the biological tissue, and spectroscopy by the spectroscopic means. A spectral image photographing device for a biological tissue, comprising a photographing means for photographing an image of the biological tissue, comprising: a light detecting means for capturing a part of the separated light, and a light detected by the light detecting means. 1. A spectral imaging device for a biological tissue, further comprising a light intensity measuring means for measuring the intensity of the spectral image of a biological tissue. (2) The spectral image photographing device for biological tissues according to claim 1, wherein the light detection means is a photometric fiber arranged between the spectroscopic means and the photographing means. (3) The photometric fiber captures fluorescent light generated from multiple locations on the biological tissue or reflected light reflected at multiple locations on the biological tissue, and the light intensity measuring means captures fluorescent light generated from multiple locations on the biological tissue. 3. A spectral image capturing device for a biological tissue according to claim 2, characterized in that the device is a means for calculating the average intensity of light or reflected light reflected at a plurality of locations on the biological tissue.