JPH0622968A - Observing device for inside of scattering body - Google Patents

Abstract

PURPOSE:To obtain an observing device for the inside of a scattering body which can efficiently detect the reflection light supplied from the wall of the scattering body, obviating the necessity of a viewfield securing means for the scattering body which scatters light. CONSTITUTION:An observing device 1 for the inside of a scattering body is equipped with a light source 2 for generating the exceedingly short pulse light in several picoseconds to several-ten picoseconds, and a long, flexible and fine insertion part 5 in which an optical fiber and an image guide are built in, in order to assist the insertion into a vein 4, radiate the pulse light to a squeezed part 3, and receive the reflected light. Further, an instantaneous photographing device 6 which synchronizes with pulse light and takes a photograph of the image of the image guide by opening a shutter in a short time, in order to carry out photographing of the squeezed part 3 suppressing the light scattering due to the blood 16, and an analyzing device 7 which processes and displays the image obtained by the instantaneous photograph device 6 in order to assist an operator and a doctor to view the image easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for observing the inside of blood-filled blood vessels, the inside of fog, dirty water, etc. where light cannot be seen due to light scattering. The present invention relates to a scatterer observation device.

[0002]

2. Description of the Related Art There is a blood vessel endoscope in which a small-diameter endoscope is inserted from a blood vessel portion close to the body surface such as a lower limb aorta to a diseased portion such as a blood vessel stenosis portion to observe and diagnose the degree of stenosis.

Light in the red to near-infrared region is highly transparent to each tissue of a living body. Using such characteristics, a method of expressing light absorption information inside a living body from transmitted light by an image such as a tomographic image or a fluoroscopic image, and further performing oxygen metabolism distribution or cancer diagnosis from spectroscopic knowledge is known. 62-
No. 72542 and Japanese Examined Patent Publication No. 2-50733.

However, when obtaining a tomographic image of the inside of a living body using transmitted light, there is a problem that the irradiated light spreads over a wide area due to strong scattering by the epidermis and internal tissues of the living body, resulting in extremely poor spatial resolution.

In order to solve this problem, the present applicant has proposed a method of limiting the light receiving angle and further removing scattered light by spatial difference, and a method of detecting light that arrives earlier in time and removing scattered light. Japanese Patent Application Laid-Open No. 3-27984
No. 3 and JP-A-4-15542.

[0006] Usually, the blood vessel is filled with blood, and when the blood vessel wall is directly observed with an angioscope, most of the light emitted from the tip of the angioscope is reflected and scattered by the blood. , The light is directly incident on the observation window of the angioscope, so that it is impossible to actually observe the image of the blood vessel wall or the like. Therefore, in an angioscope, when observing the inside of a blood vessel, physiological saline is flushed into the blood vessel from a catheter tube or an endoscope channel to remove blood, thereby securing a shutter.

[0007]

However, since this flush of physiological saline requires a large amount of physiological saline, the blood becomes thin and damages the subject, and physiological saline is repeatedly used due to blood flow. There are many problems such as having to flush the water.

In the above description, a means for forming an image in the living body with a high resolution by combining high transmittance of near infrared light and means for suppressing light scattering was shown, but the method uses transmitted light. However, the blood vessel is not imaged from the reflected light unlike the blood vessel endoscope.

The present invention has been made in view of the above circumstances, and a scatterer capable of efficiently detecting reflected light from a scatterer wall without requiring a visual field securing means for the scatterer that scatters light. An object is to provide an observation device.

[0010]

A scatterer observing device of the present invention comprises a light source for generating pulsed light, pulsed light transmission means for guiding the pulsed light generated by the light source to a subject, and scattering from the inside of the subject. An image transmission means for transmitting the reflected light as an image, and an instantaneous image pickup means for temporarily picking up the image transmitted by the image transmission means in synchronization with the pulsed light generated by the light source are provided. .

[0011]

[Operation] The instantaneous image pickup means temporarily picks up the image transmitted by the image transmission means in synchronization with the pulsed light generated by the light source.

[0012]

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

FIG. 1 is a block diagram showing the arrangement of a scatterer observation apparatus according to the first embodiment of the present invention.

The first embodiment is an embodiment in which a polarizer and a nonlinear optical material which causes the Kerr effect are used as an instantaneous image pickup device.

As shown in FIG. 1, the scatterer observation apparatus 1 of the first embodiment is easy to insert into the blood vessel 4 and the light source 2 which emits a very short pulsed light of several picoseconds to several tens of picoseconds. In order to irradiate the constricted portion 3 with pulsed light and to receive the reflected light thereof, an insertion portion 5 having a built-in optical fiber and an image guide, which is flexible and thin in extension, and light is scattered by the blood 16 through the constricted portion 3. In order to suppress and capture images, an instantaneous imaging device 6 that synchronizes with the pulsed light and opens a shutter for a short time to capture an image of the image guide, and an image obtained by the instantaneous imaging device 6 is used by an operator or a doctor. In order to make it easier to see, it comprises an analysis device 7 for processing and displaying.

The light source 2 has a wavelength of 1064 nm, a full width at half maximum of 50 ps, a repetition rate of 30 Hz, and an average output of 48 mW.
YAG laser 8 for generating the above light, and KTP for generating the second harmonic (wavelength 532 nm) of the YAG laser light,
An SHG (second harmonic generator) 9 including a non-linear optical element such as KDP and a fundamental wave (10
64 nm) and a second harmonic wave are separated by a dichroic mirror 10, and a dye laser 11 that emits light from red to near infrared light by using the second harmonic wave separated by the dichroic mirror 10 as excitation light. To be done.
It should be noted that LDS698 is used as the dye of the dye laser 11 and can be freely changed from 692 nm to 714 nm.

Further, the fundamental wave is fixed to the stepping motor 12 and the X stage 13 by a mirror 15 and then X.
Optical fiber 14 movable only in the direction (arrow in the figure)
And is guided to the instantaneous image pickup device 6. At this time, the optical path length is changed by moving the optical fiber 14 in the X direction, and the shutter timing of the instantaneous image pickup device 6 can be changed.

The insertion section 5 includes an optical fiber 17 for guiding the pulsed light of the dye laser 11 into the blood vessel 4, and the blood vessel 4.
A channel 23 composed of an image guide 19 for detecting the light radiated inside and transmitting it to the instantaneous imaging device 6, and an elastic tube 20 for inserting physiological saline or a treatment tool into the blood vessel. And the outside is covered with a flexible tube 21 made of an elastic member.
A concave lens 18 for diffusing light is provided immediately after the optical fiber 17, and an imaging lens 2 is provided immediately before the image guide 19.
2 are arranged.

The instantaneous image pickup device 6 forms an image of the base end face 24 of the image guide 19 on an image pickup surface 25 of an image intensifier (II) 26, which will be described later, and an image forming lens 27. A first polarizer 28 that limits the plane of polarization of the image; a transparent quartz container 29 filled with a liquid made of carbon disulfide or nitrobenzene that causes side refraction due to the Kerr effect when irradiated with strong light; Stepping motor 3 via belt 30 so that the surface can rotate
A second polarizer 32 interlocking with 1, and the optical fiber 1
4, an optical filter 33 for blocking the light of the fundamental wave guided by 4 and passing the light of the dye laser, and the polarizers 28, 3
2 and a container 29 filled with a liquid that causes secondary refraction by the light of the fundamental wave, the shutter is momentarily opened and projected on the imaging surface 25, and an image intensifier 26 that amplifies the projected image and the image intensifier 26. Connected to the tensioner 26, N for easy image processing
It is composed of a CCD camera 34 for converting into a TSC video signal. Further, the emitting end 34 of the optical fiber 14 faces so as to irradiate the transparent container 29 filled with carbon disulfide with the fundamental wave of the YAG laser 8, and immediately after that, the shutter operates stably. A condenser lens 35 is arranged so that the fundamental wave is condensed at the center of the transparent container 29.

The analysis device 7 includes the CCD camera 34.
A / D converter 36 for converting the image signal of FIG. 3 into a digital signal so that it can be digitally processed, an image memory 37 for accumulating a plurality of image signals, and an image processing apparatus for filtering the image and for computing between the images. 38 and a display device 38 for displaying the processing result. Further, the analysis device 7 is provided with the YAG laser light irradiation timing, the shutter timing, and shutter operation ON / OFF.
A control circuit 40 is incorporated to control the OFF state, and is connected to the YAG laser 8 and the stepping motors 12 and 31. Further, the control circuit 40 and the image processing device 38 are connected to a computer 41, and the computer 41 controls the whole of the scatterer observation device 1.

The scatterer observation apparatus 1 thus configured
The action of will be described.

First, by the YAG laser 8, 1064n
m near-infrared light is generated, and this light is passed through the SHG 9 to generate second harmonic light of 532 nm. The two wavelengths of light are separated by the dichroic mirror 10, and the second harmonic enters the dye laser 11 and the fundamental wave enters the optical fiber 14, respectively.

Here, the optical fiber 14 is in the optical axis direction (X
The shutter opening / closing timing of the instantaneous imaging device 6 can be changed by changing the optical path length to the transparent container 29.

The second harmonic wave incident on the dye laser 11 is converted into red light having a wavelength of 698 nm by the dye LDS698 as excitation light of the dye laser 11. This red light is guided to the optical fiber 17, spread by the concave lens 18, and irradiated into the blood vessel 4. In addition, from 680 nm to 120
Light in the wavelength region of 0 nm is highly permeable to blood and is suitable for observation inside blood vessels. Near infrared light may be used instead of the 698 nm red light.

The light radiated into the blood vessel is scattered in the blood 16, but a part of the light is radiated to the narrowed portion 3 and is imaged on the front end surface of the image guide 19 by the imaging lens 22. At this time, the image is an image in which the image of the stenosis 3 is buried due to light scattering by blood, and cannot be normally observed.

The image thus buried in the scattered light propagates through the image guide 19, and the image emitted from the base end face 24 is a polarizer 28 by a focusing lens 27, a transparent container 29 filled with CS2, and a polarized light. An image is formed on the image pickup surface 25 of the image intensifier 26 after passing through the child 32 and the optical filter 33. The polarization planes of the polarizers 28 and 32 are arranged so as to be perpendicular to each other, and the image does not pass through the polarizer 32 as it is.

Therefore, by irradiating the light of the fundamental wave guided by the optical fiber 14 from the direction perpendicular to the propagation direction of the image so as to be condensed by the lens 35 near the center of the inside of the transparent container 29. Only for a short time after irradiation, a secondary refraction (Kerr effect) occurs in the carbon disulfide solution in the transparent container 29, the plane of polarization of the image is converted almost vertically, and the light passes through the polarizer 32. At this time, the optical filter 25 is a bandpass filter that allows red light to pass therethrough, and blocks the fundamental wave that becomes noise.

The image obtained by the image intensifier 26 is converted into an NTSC image signal by a CCD camera, and the analyzer 7 A / D converts the image signal into an image memory 37. Remember
The image information stored in the image memory 37 is used as the image processing device 3
At 8, the image quality is improved by the contour enhancement or the inter-image calculation and displayed on the display device 39.

Therefore, the scatterer observing device 1 of the first embodiment synchronizes the timing of irradiating the carbon disulfide in the transparent container 29 with the light reflected from the narrowed portion 3 to scatter light by blood. It can be observed even without flushing with physiological saline or the like.

Further, since the irradiation light is diffused by the concave lens 18, it is safe because there is no heating due to local concentration of light, and furthermore, the fundamental wave of the light source 2 is guided to the instantaneous image pickup device 6 through the optical fiber 14. , It's safe because this powerful light doesn't fly in the air.

By rotating the polarizer 32, both a shutter image and a normal image can be taken. further,,
By condensing the light for operating the shutter by the lens 35, the shutter operation can be performed efficiently even if the light intensity is reduced.

Furthermore, by disposing a transparent container which causes secondary refraction at the intermediate position or stop position between the imaging lens 27 and the imaging surface 25 of the image intensifier 26, image distortion and uneven brightness are caused. It is possible to obtain an image with less.

When there is no light scattering other than blood, normal observation is possible by rotating the polarization plane of the polarizer 32 with the stepping motor 31 and the belt 30. Also,
Ordinary observation is also possible by making the polarizer 32 or 28 removable.

Next, the second embodiment will be described.

FIG. 2 is a configuration diagram showing the configuration of a scatterer observation apparatus according to the second embodiment of the present invention.

The second embodiment is an embodiment in which an electric shutter is used instead of the Kerr effect shutter in the first embodiment.

As shown in FIG. 2, the scatterer observation device 1a.
Is, for example, a YAG laser-excited dye laser or a semiconductor laser, an argon laser-excited titanium sapphire laser, etc., for example, full width at half maximum 4 ps, repetition 3.81 MHz.
Pulse laser 42 for generating the pulsed light, a mode rocker 43 for fixing the mode of the pulsed light to generate a single mode light, and 3.81 MHz or its frequency division in synchronization with the mode rocker 43. A frequency synthesizer 44 for generating a high frequency signal, a phase shift 45 for freely changing the phase of the high frequency signal, and an ultra-high speed amplifier 46 for amplifying the phase-shifted high frequency signal.
Image intensifier 47 that changes the amplification rate in proportion to the high frequency signal output of the output of the ultra high speed amplifier 46.
And the image of the image intensifier is NTS
A CCD camera for converting into a C signal, an image processing device 48 for accumulating NTSC signals and various image processing, and a computer 49 for controlling the frequency synthesizer 44, the phase shift 45 and the image processing device 48. . Further, there is a switching switching 51 between the image intensifier 47 and the ultra high speed amplifier 46,
In the case of normal observation, the high voltage power source 52 can be switched. The switching is controlled by the computer 49. The other configurations are similar to those of the first embodiment, and the same reference numerals are given and the description thereof is omitted.

The scatterer observing device 1 configured as described above
The operation of a will be described.

First, the pulsed laser 42 is used to generate picosecond pulsed light in the red to near infrared region. At this time, the mode rocker 43 can repeatedly generate pulsed light in a single mode. Then, this pulsed light is passed through the mirror 15 by the lens 50 to the optical fiber 1
7, and irradiates the inside of the blood vessel as in the first embodiment, and the reflected light from the stenosis or the like which is the region of interest is formed into the imaging lens 22,
It is detected through the image guide 19. Image guide 1
The end surface 24 of 9 is imaged by the imaging lens 27 on the imaging surface 25 of the image intensifier 47. The image is amplified by the image intensifier 47 several times to several hundred times, and the amplification rate is proportional to the output of the ultra high speed amplifier 46. That is, the pulsed light and the output of the ultrahigh-speed amplifier are synchronized, and the phase shift amount of the high frequency signal is controlled by the phase shift 45 so that the reflected light from the narrowed portion which is the region of interest is amplified to the maximum.

Therefore, the scatterer observing apparatus 1a according to the second embodiment is similar to the first embodiment in that the phase shift 4 is set so that the reflected light from the narrowed portion which is the region of interest is amplified to the maximum.
By controlling the amount of phase shift of the high frequency signal by 5,
Suppress light scattering by blood and observe stenosis with high resolution even without flushing with physiological saline.

Further, in the first embodiment using the Kerr effect shutter means, a highly toxic and explosive substance such as carbon disulfide and nitrobenzene is used as the sub-refractive substance, and care must be taken in handling. However, the scatterer observation apparatus 1a of the second embodiment is highly safe because it electrically realizes a high-speed shutter.

Next, a third embodiment will be described.

FIG. 3 is a configuration diagram showing a configuration of a main part of a scatterer observation apparatus according to a third embodiment of the present invention.

In the first embodiment, when performing normal observation, the polarization plane of the polarizer was rotated, but in the third embodiment, a rotation filter composed of the polarizer and a plurality of ND filters is used, and this rotation is performed. The normal observation is performed by selecting a plurality of ND filters by the filter.

As shown in FIG. 3, a disc 53 rotatable by a stepping motor 31 is arranged between a transparent container 29 filled with a substance which causes secondary refraction and an optical filter 25. Child 32, transmittance 0.1
% ND filter 54, 1% transmittance ND filter 55, and 10% transmittance ND filter 56 are attached. The other structure is the same as that of the first embodiment.

During the shutter operation, the polarizer 32 is arranged, and in the normal case, the ND filters 54, 55 and 56 are sequentially changed, and the ND filter is fixed and observed at an appropriate light amount. Other functions are the same as those in the first embodiment.

In blood, the light scattering intensity by blood is several ten times to several hundred times higher than the reflected light from the region of interest. Therefore, during normal observation, when the shutter is opened, extremely strong light is incident on the image intensifier, and in the worst case, there is a risk that the image plane is burned. However, in the third embodiment, the burning is performed. It can be easily prevented. That is, in the third embodiment, in addition to the effect of the first embodiment, the ND filters 54, 55, and 56 are sequentially changed to have a TE transmittance of 0.1.
By sequentially changing to 10%, it is possible to prevent a rapid increase in the amount of light and prevent the image intensifier 26 from being burned.

The intensity of the irradiation laser may be changed in addition to the means for replacing the ND filter.

Next, a fourth embodiment will be described.

FIGS. 4 to 6 relate to the fourth embodiment of the present invention, FIG. 4 is a configuration diagram showing a configuration of a main part of an in-scattering body observing device, FIG. 5 is a characteristic diagram for explaining transmission characteristics of an optical filter,
FIG. 6 is a timing chart showing the timing of pulsed light.

When carbon disulfide is continuously irradiated with strong light, that is, high energy, it discolors to yellow, and carbides are formed, soot-like particles float in the transparent solution. For this reason, the laser light may be absorbed or scattered by the particles and the shutter operation may become unstable. However, the fourth embodiment monitors the deterioration state of the transparent solution due to soot and the like, and In this embodiment, the transparent container is removable.

As shown in FIG. 4, a lid 57 made of a light absorbing material and capable of opening and closing so that the transparent container 29 can be removed.
When the lid 57 is opened, the transparent container 29 is attached to the outer frame 58.
In order to make it more removable, a spring 59 made of an elastic member that pushes out, an elastic member 60 that softens the impact of the transparent container 29 when the lid 57 is opened and closed, and the transparent container 29 is sandwiched between the light reflecting surface 63 and the transparent member 29. Prism 61, 62
A light generating element 64 including an LED or a laser diode that generates light in a wavelength range that does not pass through the optical filter 33; a condensing lens 65 that uses the light of the light generating element 64 as the beam light; In order to detect the light that has passed through the transparent container 29, the light detector 67 is provided with a condenser lens 66 immediately before. The rest of the configuration is similar to that of the first embodiment described above, and will be omitted. The positions of the light generating element 64 and the photodetector 67 may be exchanged.

FIG. 5 shows the transmission wavelength characteristic of the optical filter 33. λ1 is light having a wavelength to be irradiated into the blood vessel, and λ3 is light having a wavelength to perform a shutter operation. On the other hand, the wavelength used for the light generating element 64 is λ2, which is different from the wavelength. In other words, the light of λ2 and λ3 does not pass through the optical filter 33, but only the λ1 of the observation light passes through, so that the light of λ2 and λ3 which becomes noise does not enter the image intensifier 26.

FIG. 6 shows the timing characteristic. Observation light λ1
Is received by repeating about 300 ms (a). Further, since the shutter is operated in synchronization with this, λ3 for operating the shutter is repeated in the same phase as λ1 (b). On the other hand, the light of λ2 of the light generating element 64 is irradiated with the phase thereof shifted by 180 °, for example (c). Therefore, the photodetector 67 alternately receives the λ1 and λ3 and λ2 (d). Therefore, the influence of λ1 and λ3 can be removed by applying a gate to the photodetector 67 at the timing of λ2 (c). Incidentally, the photodetector 67
A bandpass filter that passes light of only λ2 may be arranged immediately before.

In the fourth embodiment thus constructed, first, the light generating element 64 generates pulsed light of wavelength λ2, and the condenser lens 65 turns it into a beam of light. This light is reflected by the reflecting surface 63 of the prism 61, irradiated so as to be substantially perpendicular to the transparent container 29 filled with the sub-refractive substance, and passed through the transparent container. The transmitted light is reflected downward in FIG. 4 by the reflecting surface 63 of the other prism 62, condensed by the condenser lens 66, and detected by the photodetector 67. When the solution in the transparent container 29 deteriorates, soot-like particles start to float or adhere to the surface of the transparent container, and the light generating element 64
The light of wavelength λ 2 is scattered or absorbed by the particles, and the amount of light incident on the photodetector 67 decreases.

That is, by notifying the operator of the decrease in the amount of light of λ2, the deterioration of the secondary refraction material, for example, carbon disulfide, is known, and if necessary, the lid 57 is opened and the transparent container 29 is replaced.

Therefore, in addition to the effects of the first embodiment,
Since the operator can accurately know the deterioration state of the sub-refraction material, when the solution in the transparent container 29 deteriorates, the transparent container 29 can be easily replaced, so that a clear image can be obtained immediately even during observation. It can be seen and therefore always a good blood vessel image can be obtained.

Next, the fifth embodiment will be described.

7 to 9 relate to the fifth embodiment of the present invention, FIG. 7 is a block diagram showing a conceptual configuration of an in-scattering body observation apparatus, and FIG. 8 is a configuration diagram showing a configuration of a main part of the in-scattering body observation apparatus. FIG. 9 is a configuration diagram showing a configuration of a main part of a modified example of the scatterer observation apparatus.

As described above, by using the car shutter, light scattering due to blood can be suppressed to some extent.
However, in the case of whole blood, there is a limit to the suppression of scattered light by the car shutter. Therefore, the fifth embodiment shows a method of using a polarizer to suppress reflection / scattering by blood.

As shown in FIG. 7A, a picosecond pulse laser 68 is provided as a conceptual structure of the in-scattering body observing apparatus of the fifth embodiment.
Pulsed light is generated by the pulsed light, and a part of the pulsed light is extracted by the beam sampler 69 and the sweep timing of the streak camera 76 is determined by the ultrafast photodetector 70. Many other lights pass through the beam sampler 69, are converted into linearly polarized light by the first polarizer 71, further pass through the beam splitter 72, and the blood vessels 7 arranged inside the blood 73.
4 is illuminated. Then, the blood 73 and the blood vessel 74
The more reflected / scattered light is again beam splitter 7
The light is reflected in a substantially vertical direction at 2 and passes through the second polarizer 75, and the streak camera 76 measures at an extremely high speed. The angle of the interface is adjusted so that specular reflection from blood and space does not enter. Further, the blood is diluted to a hematocrit value of about 5% so that the effect of the polarized light can be seen.

FIG. 7B shows a reflected pulse profile when the polarization planes of the first polarizer 71 and the second polarizer 75 are parallel to each other. The position direction indicates the movement of the blood vessel, and the edge end of the blood vessel is at the center. The reflected / scattered light from blood vessels is buried in the reflected / scattered light from blood. On the other hand, in FIG. 7C, when the first and second polarizers are arranged so that their polarization planes are perpendicular to each other, reflection / scattering by blood is suppressed and reflection / scattering light by blood vessels is suppressed. Most of them preserve the plane of polarization, but in the case of blood vessels, the plane of polarization is disturbed, and by blocking the incident light and the light that has a plane of polarization at the time of warming, it suppresses reflection / scattering by blood, Image can be measured with good S / N.

The conceptual configuration described above is applied to an actual scatterer observation apparatus. A polarizer 77 is arranged between the optical fiber 17 and the concave lens 18, and a polarizer 78 is arranged between the image forming lens 22 and the image guide 19 so that the respective polarization planes are vertical. Since the other configurations may adopt the configurations of the first or second embodiment, the description thereof will be omitted.

The pulsed light emitted from the optical fiber 17 is converted by the polarizer 77 into, for example, linearly polarized light having a polarization plane in a direction perpendicular to the paper surface in FIG. This light is spread by the concave lens 18 and irradiated to the region of interest in blood, and the reflected / scattered light is imaged on the image guide 19 through the polarizer 78 by the imaging lens 22. At this time, the polarizer 78 has a polarization plane in a direction parallel to the paper surface in FIG. 8, and out of the light reflected / scattered by the blood, the light whose polarization plane is preserved is blocked, and the S / N ratio is good. The image can be measured. Other effects,
The effect is similar to that of the first or second embodiment.

Next, a modified example will be described in which the image guide 19 is also used as the light irradiation means instead of the irradiation optical fiber 17.

As shown in FIG. 9, pulsed light for observing the inside of the blood vessel is incident on the image guide 91 by the beam splitter 79. This pulsed light is generated by the polarizer 80, λ
The pulsed light is emitted from the tip of the insertion portion 5 through the / 4 plate 81 and the imaging lens 22, and at this time, the pulsed light is linearly polarized by the polarizer 80, and the polarization direction and the optical axis are 45 °.
The light is converted into circularly polarized light by the λ / 4 plate 81 installed at.
When the circularly polarized light is applied to blood and blood vessels in this way, and the polarized light is retained from the blood and reflected / scattered in the same manner as in the case described above, the rotation direction of the circularly polarized light described above is reversed, and again. When passing through the λ / 4 plate 81, the polarization plane 90 of the polarizer 80
And the polarizer 80 cannot be transmitted.
Therefore, of the light reflected / scattered by blood, the light whose polarization plane is preserved is blocked, and the blood vessel image can be measured with a good S / N.

[0067]

As described above, according to the present invention, the in-scattering body observing device of the present invention can efficiently detect the reflected light from the scatterer wall without requiring the visual field securing means. effective.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a scatterer observation apparatus according to a first embodiment.

FIG. 2 is a configuration diagram showing a configuration of a scatterer observation apparatus according to a second embodiment.

FIG. 3 is a configuration diagram showing a configuration of a main part of a scatterer observation apparatus according to a third example.

FIG. 4 is a configuration diagram showing a configuration of a main part of a scatterer observation apparatus according to a fourth example.

FIG. 5 is a characteristic diagram illustrating transmission characteristics of an optical filter according to a fourth example.

FIG. 6 is a timing chart showing the timing of pulsed light according to the fourth embodiment.

FIG. 7 is a configuration diagram showing a conceptual configuration of a scatterer observation apparatus according to a fifth example.

FIG. 8 is a configuration diagram showing a configuration of a main part of a scatterer observation apparatus according to a fifth example.

FIG. 9 is a configuration diagram showing a configuration of a main part of a modified example of the in-vivo scatterer observation apparatus according to the fifth embodiment.

[Explanation of symbols]

 1 ... Scattering body observation device 2 ... Light source 5 ... Insertion part 6 ... Instantaneous imaging device 7 ... Analysis device 8 ... YAG laser 11 ... Dye laser 26 ... Image intensifier 28 ... Polarizer 29 ... Transparent container 32 ... Polarizer 34 ... CCD camera

[Procedure amendment]

[Submission date] August 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006] Usually, the blood vessel is filled with blood, and when the blood vessel wall is directly observed with an angioscope, most of the light emitted from the tip of the angioscope is reflected and scattered by the blood. , The light is directly incident on the observation window of the angioscope, so that it is impossible to actually observe the image of the blood vessel wall or the like. Therefore, in the angioscope, when observing the inside of the blood vessel, physiological saline is flushed into the blood vessel from the catheter tube or the endoscope channel to eliminate blood, thereby securing the visual field .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

The light source 2 has a wavelength of 1064 nm, a full width at half maximum of 50 ps, a repetition rate of 30 Hz, and an average output of 480 m.
YAG laser 8 for generating W light, and KT for generating the second harmonic (wavelength 532 nm) of the YAG laser light
An SHG (second harmonic generator) 9 composed of a non-linear optical element such as P or KDP, a dichroic mirror 10 for separating the fundamental wave (1064 nm) of the light and a second harmonic, and the second dichroic mirror 10 for separating the dichroic mirror 10. It is composed of a dye laser 11 which emits light from red light to near-infrared light by using harmonics as excitation light. It should be noted that LDS698 is used as the dye of the dye laser 11 and can be freely changed from 692 nm to 714 nm.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

The analysis device 7 includes the CCD camera 34.
A / D converter 36 for converting the image signal of FIG. 3 into a digital signal so that it can be digitally processed, an image memory 37 for accumulating a plurality of image signals, and an image processing apparatus for filtering the image and for computing between the images. 38 and a display device 39 for displaying the processing result. Further, the analysis device 7 is provided with the YAG laser light irradiation timing, the shutter timing, and shutter operation ON / OFF.
A control circuit 40 is incorporated to control the OFF state, and is connected to the YAG laser 8 and the stepping motors 12 and 31. Further, the control circuit 40 and the image processing device 38 are connected to a computer 41, and the computer 41 controls the whole of the scatterer observation device 1.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Therefore, by irradiating the light of the fundamental wave guided by the optical fiber 14 from the direction perpendicular to the propagation direction of the image so as to be condensed by the lens 35 near the center of the inside of the transparent container 29. Only for a short time after irradiation, a secondary refraction (Kerr effect) occurs in the carbon disulfide solution in the transparent container 29, the plane of polarization of the image is converted almost vertically, and the light passes through the polarizer 32. At this time, the optical filter 33 is a bandpass filter that allows red light to pass therethrough, and blocks the fundamental wave that becomes noise.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

As shown in FIG. 2, the scatterer observation device 1a.
Is, for example, a YAG laser-excited dye laser or a semiconductor laser, an argon laser-excited titanium sapphire laser, etc., for example, full width at half maximum 4 ps, repetition 3.81 MHz.
Pulse laser 42 for generating the pulsed light, a mode rocker 43 for fixing the mode of the pulsed light to generate a single mode light, and 3.81 MHz or its frequency division in synchronization with the mode rocker 43. A frequency synthesizer 44 for generating a high frequency signal, a phase shift 45 for freely changing the phase of the high frequency signal, and an ultra-high speed amplifier 46 for amplifying the phase-shifted high frequency signal.
Image intensifier 47 that changes the amplification rate in proportion to the high frequency signal output of the output of the ultra high speed amplifier 46.
And the image of the image intensifier is NTS
A CCD camera 34 for converting into a C signal, an image processing device 48 for accumulating NTSC signals and various image processing, and a computer 49 for controlling the frequency synthesizer 44, the phase shift 45 and the image processing device 48 are configured. It Further, there is a switching switching 51 between the image intensifier 47 and the ultra-high speed amplifier 46, and it is possible to switch to the high voltage power source 52 for normal observation. The switching is controlled by the computer 49. The other configurations are similar to those of the first embodiment, and the same reference numerals are given and the description thereof is omitted.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

In blood, the light scattering intensity by blood is several ten times to several hundred times higher than the reflected light from the region of interest. Therefore, during normal observation, when the shutter is opened, extremely strong light is incident on the image intensifier, and in the worst case, there is a risk that the image plane is burned. However, in the third embodiment, the burning is performed. It can be easily prevented. That is, in the third embodiment, in addition to the effect of the first embodiment, the transmittances of the ND filters 54, 55 and 56 are sequentially changed to 0.1 to 10.
By sequentially changing to 10%, it is possible to prevent a rapid increase in the amount of light and prevent the image intensifier 26 from being burned.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction content]

FIG. 7B shows a reflected pulse profile when the polarization planes of the first polarizer 71 and the second polarizer 75 are parallel to each other. The position direction indicates the movement of the blood vessel, and the edge end of the blood vessel is at the center. The reflected / scattered light from blood vessels is buried in the reflected / scattered light from blood. On the other hand, in FIG. 7C, when the polarization planes of the first polarizer and the second polarizer are arranged to be perpendicular to each other, reflection / scattering by blood is suppressed, and the edge image of the blood vessel is clearly captured. Is it understood
It In other words, most of the reflected / scattered light from blood vessels preserves the plane of polarization, whereas in the case of blood vessels, the plane of polarization is disturbed and the light with the same plane of polarization as the incident light is blocked, so Suppresses reflection / scattering and displays blood vessel images in S / N
It can be measured well.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Change

[Correction content]

As shown in FIG. 9, the beam splitter 79 images the pulsed light for observing the inside of the blood vessel.
It is incident on the guide 19 . This pulsed light is generated by the polarizer 80, λ
The pulsed light is emitted from the tip of the insertion portion 5 through the / 4 plate 81 and the imaging lens 22, and at this time, the pulsed light is linearly polarized by the polarizer 80, and the polarization direction and the optical axis are 45 °.
The light is converted into circularly polarized light by the λ / 4 plate 81 installed at.
When the circularly polarized light is applied to blood and blood vessels in this way, and the polarized light is retained from the blood and reflected / scattered in the same manner as in the case described above, the rotation direction of the circularly polarized light described above is reversed, and again. After passing through the λ / 4 plate 81, the polarization plane of the polarizer 80 and the
It becomes 0 °, and the polarizer 80 cannot be transmitted. Therefore, of the light reflected / scattered by blood, the light whose polarization plane is preserved is blocked, and the blood vessel image can be measured with a good S / N.

[Procedure Amendment 9]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure Amendment 10]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (1)

[Claims] 1. A light source that generates pulsed light, a pulsed light transmission unit that guides the pulsed light generated by the light source to a subject, and an image transmission unit that transmits the light scattered and reflected from the inside of the subject as an image. And a momentary image pickup means for temporarily picking up an image transmitted by the image transmission means in synchronism with the pulsed light generated by the light source.