JPH06154228A - Optical tomographic imaging - Google Patents

Abstract

PURPOSE:To provide an optical tomographic imaging apparatus which facilitates the measurement of a degree of invasion of lesion. CONSTITUTION:An image of the surface of an affected part 3 can be observed with naked eyes with a colposcope 2 while a surface observation image is displayed on a monitor 7 through a TV camera 5. Light with low interference generated in an SLD31 is transmitted with an optical fiber 33a and admitted to the side of the affected part 3 through an optical system of the colposcope 32 from a scanning section 21. A mirror 55 is moved to change an optical path length to obtain a depth-wise tomographic image of the affected part 3, which is outputted to a monitor 7 through a superimposing circuit 18. This enables the displaying of a tomographic image together with the surface observation image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical tomographic imaging apparatus for obtaining a tomographic image of a subject using low coherence light.

[0002]

2. Description of the Related Art Conventionally, for diagnosing cervical cancer, the surface of the cervix is observed using a colposcope. In colposcope, the degree of infiltration in the depth direction of the lesion is estimated from the morphology of the surface of the cervix, or biopsy is performed from the site that seems to be the most advanced, and it is determined by histological diagnosis.
The treatment policy was decided.

[0003]

However, in the above method, the accuracy rate is low (affected by the doctor's proficiency level, biopsy site, etc.), and it is possible to remain after treatment by transpiration / circle-cutting etc. by laser. There is a problem that there is a property.

[0004] Further, the biopsy usually takes only one part of the tissue, and there is a possibility that the lesion part cannot be surely collected. If a tissue is to be collected over a wide range in order to reliably collect a lesioned part, a wide range of biopsies or a wide range of resections with a scalpel or the like is required, which causes a great pain to the patient.

The present invention has been made in view of the above points, and an object thereof is to provide an optical tomographic imaging apparatus capable of easily measuring the infiltration degree of a lesion.

[0006]

Means and Actions for Solving the Problems Illumination light emitting means for emitting illumination light, an objective optical system for forming an image of the surface of a subject illuminated by the illumination light, and photoelectric conversion of the image based on the objective optical system. An image pickup device having an image pickup element for generating low coherent light, a low coherent light generating unit for generating low coherent light, and guiding the low coherent light into the image pickup unit, and an end surface on the tip side in the image pickup unit. From the low coherence light, which emits the low coherence light to the subject side from, and guides the reflected light reflected on the subject side, and the reflected light guided by the light guide member and the low coherence light. Interfering light extraction means for interfering with the generated reference light to extract an interference signal corresponding to the interfering interference light, optical path length changing means for changing the optical path length on the reference light side or the reflected light side, and the interference. Performs signal processing on the signal and constructs a tomographic image of the subject in the depth direction By providing the signal processing means for displaying the image and the tomographic image captured by the image sensor at the same time, observation of the surface imaged by the image capturing means (image captured image) and Since the internal tomographic image can be obtained, the range of the lesion portion can be easily known from this tomographic image.

Therefore, there is a case where the biopsy is not required, and even when the biopsy is performed, the required biopsy site can be minimized and the pain of the patient can be greatly reduced. Also, the burden on the operator is reduced.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 relate to a first embodiment of the present invention, FIG. 1 shows an optical tomographic imaging apparatus of the first embodiment, and FIG.
Shows the structure of the scanning unit, and FIG. 3 shows that a tomographic image is displayed on the monitor together with the image of the affected part.

The optical tomographic imaging apparatus 1 of the first embodiment includes a colposcope 2 capable of observing an affected part 3 such as cervical cancer of a living body, and a light beam having low coherence for performing optical tomographic imaging. An optical tomographic image observing device 4 for guiding the light to the scope 2 side and detecting the reflected light from the affected part 3 side as measuring light by interfering with the reference light, and this optical tomographic image observing device 4
The signal processing device 6 performs signal processing for the interference signal detected by the signal processing device, signal processing for the TV camera 5 attached to the colposcope 2, and the like, and a monitor 7 for displaying a video signal output from the signal processing device 6. On the monitor 7, a (surface) observation image of the affected area 3 obtained by the TV camera 5 and an optical tomographic image of light with low coherence are superimposed and displayed.

The colposcope 2 is a binocular, and a common objective lens 11 having a large aperture is attached to the tip of the lens barrel 8 in order to form an optical image of the affected area 3 illuminated by illumination light from an illumination means (not shown). The variable power lens 12a12b and the beam splitter 1 are opposed to the objective lens 11.
3a and 13b, imaging lenses 14a and 14b, and eyepieces 15a and 15b are arranged on the respective optical axes.

The light split by the beam splitter 13a forms an image on a CCD (not shown) of the TV camera 5 via the image forming lens 16. The output signal of the TV camera 5 is input to the video signal processing circuit 17, the video signal is generated, and is mixed by the superimposing circuit 18 with the video signal from the optical tomographic image observation device 4 side via the arithmetic device 19. , Is output to the monitor 7, and is displayed on the monitor 7, for example, as shown in FIG.

The other beam splitter 13b is the scanning unit 2
The light from the side of the optical tomographic image observation device 4 enters through the beam splitter 1, and the light reflected on the side of the affected part 3 is reflected by the beam splitter 13
The light is guided to the optical tomographic image observation device 4 side via b. The scanning unit 21 two-dimensionally scans light with low coherence by the biaxial control unit 22.

In the optical tomographic image observation device 4, an ultra-high brightness light emitting diode (hereinafter abbreviated as SLD) 31 as a light source for generating light with low coherence is arranged. This SLD
Reference numeral 31 denotes, for example, a wavelength of 830 nm, and the coherence length is, for example, about several tens to several thousands μm. This light is converted into linearly polarized light having a predetermined polarization plane through the lens 32a, the polarizer 32b, and the lens 32c, and the single mode The light enters from one end face of the optical fiber 33a and is transmitted to the other end face (referred to as a front end face) side.

This optical fiber 33a has a PANDA on the way.
The other single mode optical fiber 33b by the coupler 34
Is optically coupled to. Therefore, this coupler 34
It is divided into two parts and transmitted. Optical fiber 33a
The tip side of (from the coupler 34) is wound around a piezoelectric element such as lead zirconate ceramics (abbreviated as PZT) 35.

A drive signal is applied to the PZT 35 from the oscillator 36, and the PZT 35 forms a modulator 37 which modulates the transmitted light by vibrating the optical fiber 33a. The frequency of this drive signal is, for example, 5 to 20 KHz. The modulated light is emitted from the tip end surface of the optical fiber 33a to the scanning unit 21.

As shown in FIG. 2, a condenser lens 38 is arranged in the scanning section 21 so as to face the tip end surface of the optical fiber 33 a, and the light is incident on the mirror 39 via the condenser lens 38. The mirror 39 is attached to the shaft of a first gear box 41b provided on the shaft of the first motor 41a and is rotated by the first motor 41a controlled by the biaxial control unit 22 as shown by an arrow Y1. Is rotated.

The first motor 41a and the first gear box 41b are supported by a support member 41c, and the support member 41c is a second gear box arranged so as to be orthogonal to the axis of the first motor 41a. It is attached to the shaft of 41d. The second gear box 41d is provided on the shaft of the second motor 41e.

When the second motor 41e controlled by the biaxial controller 22 is rotated, the mirror 39 is rotated as indicated by arrow Y2. When the mirror 39 is rotated as indicated by arrows Y1 and Y2, the two-dimensionally scanned light is guided to the beam splitter 13b side, and the reflected light from the beam splitter 13b side is reflected on the tip surface of the optical fiber 33a. Guide light to.

As shown in FIG. 1, the beam splitter 13b
The light guided to the side is a variable power lens 12b, an objective lens 11
Is emitted to the affected part 3 side through two-dimensional scanning, and the affected part 3 is two-dimensionally scanned, and part of the light reflected by the internal tissue of the affected part 3 is guided to the tip surface of the optical fiber 33a via the beam splitter 13b. It

Almost half of this light is moved to the optical fiber 33b by the coupler 34 and guided to the interference light detecting section 44. The optical fiber 33b also transmits the light reflected by the mirror 45 attached to the tip surface (reference light obtained by branching the light from the SLD 31 side by the coupler 34), and guides it to the interference light detection unit 44. That is, the light guided to the interference light detection unit 44 side is transmitted to the optical fiber 33a side and becomes a mixture of the measurement light reflected by the affected part 3 and the reference light reflected by the mirror 45.

The mirror 4 in the optical fiber 33b
Between the tip end to which 5 is fixed and the coupler 34, the optical path length by the optical fiber 33a wound by the modulator 37,
A compensating ring 46 is provided for substantially compensating the optical path length to the affected part 3 side. The light emitted from the rear end face of the optical fiber 33b is converted into a parallel light flux by the lens 47, and the analyzer 48
After the light component of the polarization plane is extracted by the half mirror 4
At 9, the light is split into transmitted light and reflected light.

The reflected light is reflected by the mirror 51 and is condensed by the lens 52 (the light component further transmitted by the half mirror 49), and the photodiode (PD) as a photodetector.
Is received). The light transmitted through the half mirror 49 is reflected by a mirror 55 attached to the X-stage 54, (the light component reflected by the half mirror 49) is condensed by a lens 52, and is received by a PD 53. The X-stage 54 is, for example, a stepping motor 56.
Is moved in the direction X facing the end face of the optical fiber 33b, and the optical path length can be changed.

When obtaining an optical tomographic image of the affected area 3,
The optical path length until the light reflected by the mirrors 45 and 55 is incident on the PD 53, and the optical path length until the light returning from the affected part 3 side via the optical fiber 33a is reflected by the mirror 51 and incident on the PD 53. Are set to be almost equal.

That is, by changing the position of the mirror 55 to change the optical path length on the reference light side, the optical path length on the measurement light side, which is equal to the optical path length on the reference light side, changes in the depth direction of the affected part 3. . Then, these two lights having almost the same optical path length interfere with each other and are detected by the PD 53.

The optical path length between the half mirror 49 and the mirror 51 and the optical path length between the half mirror 49 and the mirror 55 are set so as to always deviate from at least the interference range of light having low coherence. When the half mirror 49 splits the transmitted light and the reflected light by itself and then mixes them in the half mirror 49, the interference is set not to occur.

The signal photoelectrically converted by the PD 53 is input to the lock-in amplifier (not shown) of the arithmetic unit 19 which constitutes the signal processing unit 6 together with the drive signal of the oscillator 36 or the signal of the same phase as the reference signal, Heterodyne detection is performed in which a signal component having the same frequency as the reference signal in the signal from the PD 53 is extracted, and a signal component having the same phase is extracted and further detected and amplified. Then, the data is input to a computer unit (not shown) inside the arithmetic unit 19.

The scope of the colposcope 2 displayed on the monitor 7, as shown in FIG. 3 (a), is displayed in the computer section on the basis of the coordinate data designated by the mouse 57 and the magnification signal input from the magnification detection circuit 58. The coordinates of the range of the cursor K superimposed on the image G1 are calculated.

From the calculation result of the coordinates, the rotation amounts of the motors 41a and 41e of the scanning unit 21 are determined, and the biaxial control unit 22
The lens 57 is rotationally driven to scan the area designated by the mouse 57. The signal obtained by the optical scanning is temporarily stored in an image memory (not shown), and when a scanning image of a predetermined range in the depth direction is obtained by scanning the mirror 55 by rotation of the motor 56, the image data of the image memory is displayed. A video signal corresponding to the optical tomographic image is converted into a video signal by the video signal processing unit, and is output to the monitor 7 via the superimposing circuit 18.

In this embodiment, when the video signal corresponding to the optical tomographic image is output from the arithmetic unit 19 side, the TV camera 5
The scope image G1 imaged in 1 is reduced and displayed simultaneously with the optical tomographic image G2 as shown in FIG.

According to this embodiment, the affected part 3 such as the cervix
Since the scope image G1 and the tomographic image G2 of the surface can be displayed on the monitor 7 at the same time, the lesion site and the extent of the lesion site in the depth direction can be grasped from the tomographic image G2. Therefore, the range in the depth direction of the lesion can be determined without the need to perform biopsies many times. Therefore, the patient's pain can be reduced (since biopsy is not required to be performed many times), and the surgeon can also reduce the burden because the biopsy is not required to be performed many times.

Further, the scanning section 2 is provided by the optical fiber 33a.
Since the light is guided to the colposcope 2 via 1, the diameter of the lens barrel 8 can be reduced. Also, the beam splitter 13b
Since it is configured to guide light to, it is possible to have a unitized structure that can be attached to and detached from the beam splitter 13b. With this configuration, when the colposcope 2 is used, it is possible to use the unit portion for obtaining an optical tomographic image by selecting use / non-use according to need.

FIG. 4 shows a TV probe 61 in a modification of the first embodiment. In this modification, a TV probe 61 including a CCD 62 instead of the colposcope 2 shown in FIG.
Was used.

In this TV probe 61, an objective lens 64, a variable power lens 65, a dichroic mirror 66, an image forming lens 67, and a CCD 62 are sequentially arranged on a cylindrical probe main body 63, and signals from the CCD 62 are input to a video signal processing circuit 17. To be done. Further, the scanning unit 21 is attached to the reflection light path side of the dichroic mirror 66 to guide the light of the optical fiber 33a to the dichroic mirror 66 side and guide the light from the dichroic mirror 66 side to the optical fiber 33a side. It has become.

As shown in FIG. 5, the dichroic mirror 66 has a reflectance intensity with respect to wavelength that is approximately 1 for light in the vicinity of the boundary wavelength between the visible region and the near infrared region and in the near infrared region.
A material having a property of reflecting 00% and transmitting almost 100% of light in the visible region is used. The wavelength of the SLD 31 is set in the near infrared region, is constantly reflected by the dichroic mirror 66, and does not adversely affect the CCD 62 that images with light in the visible region.

That is, the light from the optical fiber 33a is reflected by the dichroic mirror 66 and guided to the objective lens 64 side, and the reflected light of the SLD 31 returning from the objective lens 64 side to the dichroic mirror 66 is reflected by the dichroic mirror 66. The light is guided to the optical fiber 33a side. On the other hand, the light in the visible region passes through the dichroic mirror 66 and forms an image on the CCD 62.

The other structure is the same as that of the first embodiment.
In this modified example, the image displayed on the monitor 7 is observed without the naked-eye observation optical system in the colposcope 2 in the first example. FIG. 6 shows an image G captured by the CCD 62 displayed on the monitor 7. The tomographic image can be observed only on a predetermined portion (in this modification, the central index S) on the monitor 7.

Therefore, the operator moves and sets the TV probe 61 so that the region desired to be observed is located at the center. The range of the tomographic image can be variably set within the scanning range of the biaxial control unit 21. As shown in FIG. 7, a ring-shaped rubber 69 is attached in front of the objective lens 64 of FIG. 4, and the probe tip is pressed against a contactable portion such as the cervix to obtain an optical tomographic image. You may do it.

FIG. 8 shows an optical tomographic imaging apparatus 71 according to the second embodiment of the present invention. The optical tomographic imaging apparatus 71 of the second embodiment includes an endoscope 72 capable of observing an arbitrary site in a body cavity, a light source device 73 for supplying illumination light to the endoscope 72, and an endoscope 72. A light guide member for guiding light with low coherence provided is connected to an optical interference device 74 for performing optical tomographic imaging, and a monitor 75 as a display device for displaying an optical tomographic image by the optical interference device 74. Composed.

The optical interference device 74 uses an optical interference section 76 for obtaining an electric signal corresponding to the interference light for generating an optical tomographic image using light of low coherence, and an electric signal of the optical interference section 76. And a signal processing unit 77 for processing and generating a video signal corresponding to the optical tomographic image. The video signal is displayed on the monitor 75.

The endoscope 72 has an elongated and flexible insertion portion 78 and a wide operation portion 79 provided at the rear end of the insertion portion 78, and a side portion of the operation portion 79. The cable is extended from the outside.

The light guide 81 is inserted into the insertion portion 78, and the connector provided at the cable-side end of the light guide 81 can be detachably attached to the light source device 73. By mounting, the white illumination light of, for example, the xenon lamp 82 inside the light source device 73 is condensed by the condenser lens 83 and supplied to the end portion of the light guide 81, and this illumination light is transmitted by the light guide 81 and is inserted into the insertion portion. 78 tip 8
The light is emitted to the side of the insertion portion 78 from the other end surface fixed to the illumination window provided on the side portion of No. 4.

By the illumination light emitted from the side-view illumination window, an optical image of the illuminated site of interest such as the luminal organ 85 is attached by the objective lens 86 attached to the side-view observation window adjacent to the illumination window. It is tied to that focal plane. A CCD 87 is arranged at the position of this focal plane and photoelectrically converts the optical image.

A CCD drive signal is applied from the CCD drive circuit 88 to the CCD 87 to read out a photoelectrically converted signal, and a video processor (hereinafter referred to as VP) as video signal processing means is read out via a video signal line 89. Input) 90.

The output signal of the VP 90 is output to the monitor 75 via the superimposing circuit 91, and the CCD 87
The endoscopic image picked up in is displayed.

A bending operation mechanism (not shown) is provided in the operation portion 79, and the bending portion formed at the rear end of the tip end portion 84 can be moved vertically or horizontally in any direction by operating the bending operation knob. It can be bent. The endoscope 72 is provided with an optical fiber 9 for transmitting light of lower coherence.
2 is inserted.

The tip of the optical fiber 92 is fixed on the central axis of the tip 84, and a gradient index lens (hereinafter referred to as SELFOC lens) 93 is attached to the tip surface. The optical interference portion 76 is provided at the rear end side of the optical fiber 92.
Is connected to the tip end surface of the optical fiber 33a, and the light of the SLD 31 is guided through the optical fiber 33a.

The light of the SLD 31 is incident on one end face of the single mode optical fiber 33a via the lens 32 and is transmitted to the other end face side. This optical fiber 33a is a coupler 34 on the way, and the other single mode optical fiber 33
Optically coupled to b. Therefore, this coupler 3
The four parts are branched into two and transmitted. Optical fiber 33
The tip side of a (from the coupler 34) is wound around a piezoelectric element such as a PZT 35.

A drive signal is applied from the oscillator 36 to the PZT 35, and the PZT 35 forms a modulator 37 which modulates the transmitted light by vibrating the optical fiber 33a. The modulated light is emitted from the front end surface of the optical fiber 33a, is incident on the optical fiber 92 which is in contact with the front end surface, and the front end portion 8
The light is transmitted to the end face on the fourth side and is emitted from this end face through the SELFOC lens 93.

A lens 94 arranged so as to face the SELFOC lens 93 forms a parallel beam, which is reflected at a right angle by the inclined surface of the prism 96 attached to the gear 95 and emitted to the side of the insertion portion 78. It The gear 95 is provided with an opening at the center so that light can pass therethrough. This gear 95 is a gear 97a attached to the rotating shaft of the motor 97.
Meshes with.

Therefore, when the motor 97 rotates, the prism 96 rotates, and the light guided by the optical fiber 92 is radially emitted around the central axis of the insertion portion 78.

The motor 97 is fixed to a motor fixing base 98 having a rack formed on the back surface. This rack is a pinion gear 99a attached to the rotating shaft of the motor 99.
Meshes with.

When the motor 99 rotates, the rack moves and the motor 97 fixed to the motor fixing base 98,
A gear 97a attached to the rotating shaft and a gear 95 for maintaining a meshed state with the gear 97a are interlocked with each other to move in the axial direction of the insertion portion 78, that is, the longitudinal direction. The rotation amounts of these motors 97 and 99 are controlled by the position control device 101 in the signal processing unit 77.

The light reflected by the hollow organ 85 passes through the prism 96, the lens 94 and the SELFOC lens 93 and is incident on the front end surface of the optical fiber 92.
The light is incident on the front end face of the optical fiber 33a from the rear end face. This light is coupled by a coupler 34 and almost half of it is an optical fiber 33.
b, and is guided to the interference light detection unit side together with the reference light reflected by the mirror 45 arranged opposite to the tip end surface of the optical fiber 33b.

In the first embodiment, the optical path length changing mechanism for changing the optical path length of the reference light is provided on the side of the interference light detecting portion. In this embodiment, however, the optical path length changing mechanism is provided on the tip surface of the optical fiber 33b. .

That is, the mirror 45 in the embodiment of FIG.
Is attached to the X-stage 54, and the motor 56 is moved in a direction in which the optical path length of the reference light is changed to change the optical path length. A lens 45a is arranged between the tip end surface of the optical fiber 33b and the mirror 45. Motor 5
The rotation control unit 6 is controlled by the position control device 101.

The light emitted from the rear end face of the optical fiber 33b passes through the lens 52 and is received by the PD 53. PD53
The signal photoelectrically converted by is amplified by the preamplifier 102, and then input to the signal input terminal of the lock-in amplifier 103 of the signal processing unit 77. A reference signal is input from the oscillator 36 to the reference signal input terminal of the lock-in amplifier 103,
Heterodyne detection and amplification are performed.

The output of the lock-in amplifier 103 is input to a computer 105 via a digital voltmeter (hereinafter abbreviated as DVM) 104, and corresponds to a tomographic image from a signal obtained by the light guided by the optical fiber 92. Control for generating image data is performed.

That is, a control signal is sent to the position control device 101 to control the rotation amounts of the motors 97 and 99, and to control the change of the optical path length due to the scanning of the light beam and the rotation control of the motor 56. In scanning the light beam and changing the optical path length, the PD
The signal obtained from 53 is stored in the temporary image memory.

For example, when image data for one frame is obtained, the image data is output to the VP 106, and this VP 106 converts it into a video signal, and the monitor 7 via the superimpose circuit 91.
5, and superimposes the image on the CCD 87 so that an optical tomographic image is displayed.

The motor 99 is rotated to rotate the prism 96.
When is moved in the longitudinal direction, the movement changes the optical path length on the measurement light side. Therefore, a control signal is sent to the position control device 101 to rotate the motor 56 to compensate for the change in the optical path length. To control. By this control, the image distortion due to the change in the optical path length is corrected. According to this embodiment, in addition to the effects of the first embodiment, there is an advantage that a three-dimensional tomographic image can be obtained.

FIG. 9 shows an optical tomographic imaging apparatus 111 according to the third embodiment of the present invention. The optical tomographic imaging apparatus 111 according to the third embodiment includes an endoscope 112 capable of observing an arbitrary site in a body cavity, a light source device 73 for supplying illumination light to the endoscope 112, and an endoscope 112. An optical interference device 1 that is connected to a provided light guide member that guides light with low coherence and performs generation of light for optical tomographic imaging and detection of interference light.
14, a signal processing unit 115 that performs signal processing such as generation of a video signal corresponding to an optical tomographic image from the signal by the optical interference device 114, and a display device that displays the video signal output from the signal processing unit 115. Monitor 116.

In the third embodiment, the dichroic mirror 117 is used to obtain a tomographic image of the living tissue 118 in the endoscopic observation field of view.

Like the second embodiment, in the endoscope 112, the light guide 81 is inserted into the insertion portion 78, transmits the illumination light of the lamp 82 of the light source device 73, and is fixed to the distal end portion 84. Glass plate 1 attached to the lighting / observation window from the surface
The front side of the living tissue 118 is illuminated via 19. In this embodiment, the tip end side of the light guide 81 is divided into two.

An objective lens 86 is arranged inside the glass plate 119 and forms an image on the CCD 87. This CCD8
7 is driven by the CCD drive circuit 88, and the photoelectrically converted signal is VP in the signal processing unit 115 via the video signal line 89.
The video signal input to the 90 and output from the VP 90 is input to the monitor 116 via the superimpose circuit 91, and as shown in FIG. Is displayed.

A dichroic mirror 117 tilted by 45 ° with respect to the optical axis of the objective lens 86 is arranged between the objective lens 86 and the CCD 87. The dichroic mirror 117 having the characteristics shown in FIG. 5 is used, which transmits light in the visible region and reflects light in the near infrared region. The prism 121 is arranged on the reflection optical path of the dichroic mirror 117.

This prism 121 is attached to a movable base 122 having a rack formed on the back surface. The tip of the optical fiber 92 is attached to the movable table 122 with an optical fiber fixing member, and the light emitted from the tip surface of the optical fiber 92 is reflected by the prism 121 and guided to the dichroic mirror 117 side. The light reflected by the dichroic mirror 117 is reflected by the prism 121 and guided so as to be incident on the tip surface of the optical fiber 92.

The rack of the movable table 122 meshes with the pinion gear 125 attached to the tip of the shaft 124 connected to the rotating shaft of the stepping motor 123 housed in the operating section 79, and the stepping motor 123 rotates. The movable table 122 is moved in a direction parallel to the optical axis of the objective lens 86, that is, in the longitudinal direction of the insertion section 78.

For example, when the movable table 122 is moved rearward from the state shown in FIG. 9, the prism 121 is also moved rearward, so that the light reflected by the prism 121 is guided as shown by the dotted line. It Therefore, by moving the prism 121, light is vertically scanned on the living tissue 118 side, and a tomographic image corresponding to this scanning direction can be obtained.

The optical interference device 1 is provided at the rear end of the optical fiber 92.
14 is connected to the end surface of the optical fiber 33a, and the SLD3
The low coherence light from the optical fiber 1 is guided to the optical fiber 92 side, and the reflected light from the optical fiber 92 side is guided to the optical fiber 33.
Light is guided to the a side.

In the optical interference device 114, the output of the PD 53 is input to the lock-in amplifier 103, a signal component having the same phase as the reference signal is extracted and detected, and then the signal processing unit 11 is executed.
5 is input to the computer 126.

The computer 126 controls the rotation of the stepping motor 123 and the rotation of the motor 56.
Also, the process of generating a video signal corresponding to the tomographic image is performed,
By outputting to the superimpose circuit 91,
As shown in 0, a tomographic image is simultaneously displayed on the monitor 116 adjacent to the endoscopic image.

Further, the computer 126 displays a cursor 128 indicating the area where the tomographic image is measured in the endoscopic image as shown in FIG. By this display, the region where the tomographic image is obtained can be known on the observed image, which is convenient for diagnosis. This cursor 128 can be erased when it is unnecessary. In the configuration of the optical interference device 114, the same components as those of the optical interference unit 76 shown in FIG. 8 are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, a glass plate 119 that emits visible illumination light and receives visible observation light is provided on the distal end surface of the endoscope 112, and as shown in FIG.
An observation image can be obtained in a state in which the distal end surface of 8 is pressed against the tissue in the body cavity such as the stomach inner wall 129.

Further, in the close contact state where it is pressed against the tissue in the body cavity,
Light with low coherence for obtaining an optical tomographic image is emitted to the tissue side in the body cavity through the glass plate 119, and reflected light on the tissue side in the body cavity can be taken in, so that the tissue in the body cavity in the visible observation visual field can be captured. A tomographic image of the central part is obtained. This close contact can prevent blurring that occurs when the organ is moving or the tip of the insertion portion 78 fluctuates, and a clear observation image and tomographic image without blurring can be obtained. Therefore, in this embodiment, the observation system is set to a focal length of about suitable for observing the surface of the glass plate 119. Note that the optical fiber 92 inserted through the endoscope 112 and the optical fiber 3 of the optical interference device 114
3a and 3a may be integrated.

FIG. 12 shows an optical tomographic imaging apparatus 131 according to the fourth embodiment of the present invention. In the endoscope 132 in the fourth embodiment, the front end surface of the image guide 133 is arranged on the photoelectric conversion surface of the CCD 87 in the endoscope 112 of FIG. 9, and the imaging lens 134 is opposed to the rear end surface of the image guide 133. Is arranged so that the image transmitted by the image guide 133 is connected to the CCD 87 arranged at the image forming position by the image forming lens 134.

In this embodiment, the image guide 133 is inserted into the insertion portion 78, the observation image is transmitted to the rear end face of the operation portion 79 side, and the lens 134 forms an image on the CCD 87. Others are the same as the configuration described in the third embodiment. In this embodiment, the endoscopic image displayed on the monitor 116 has a circular shape. The operation and effect of this embodiment are almost the same as those of the third embodiment. Note that when changing the optical path length, the optical path length on the measurement light side may be changed, not limited to the reference light (reference light) side serving as a reference. Further, when obtaining an image of the surface of a subject such as a living body, it is not limited to an image by visible light, and may be an image of infrared rays, ultraviolet rays, or the like.

[0077]

As described above, according to the present invention, it is possible to simultaneously display a surface observation image of a subject with visible light or the like and a tomographic image with low coherence light, so that the lesion tissue is deep. It is possible to easily determine the range existing in the vertical direction.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an optical tomographic imaging apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a scanning unit.

FIG. 3 is an explanatory diagram showing that a tomographic image is displayed on a monitor together with an image of an affected area.

FIG. 4 is a diagram showing a TV probe according to a modification of the first embodiment.

FIG. 5 is a characteristic diagram showing spectral characteristics of a dichroic mirror.

FIG. 6 is a diagram showing that an index corresponding to a range in which a tomographic image is obtained is displayed on a monitor screen.

FIG. 7 is a cross-sectional view showing the tip side of the TV probe in the modification example of FIG. 6;

FIG. 8 is a configuration diagram showing an optical tomographic imaging apparatus according to a second embodiment of the present invention.

FIG. 9 is a configuration diagram showing an optical tomographic imaging apparatus according to a third embodiment of the present invention.

FIG. 10 is a diagram showing an image display example on a monitor.

FIG. 11 is a view showing that the distal end surface of the insertion portion can be observed while being pressed against the tissue in the body cavity.

FIG. 12 is a configuration diagram showing an optical tomographic imaging apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical tomographic imaging device 2 ... Colposcope 3 ... Affected part 4 ... Optical tomographic image observation device 5 ... TV camera 6 ... Signal processing device 7 ... Monitor 8 ... Lens barrel 11 ... Objective lens 12a, 12b ... Variable-magnification lens 13a, 13b ... Beam splitters 15a, 15b ... Eyepieces 17 ... Video signal processing circuit 18 ... Superimposing circuit 19 ... Computing device 21 ... Scanning unit 22 ... Biaxial control unit 31 ... SLD 32b ... Polarizers 33a, 33b ... Optical fiber 34 ... Coupler 35 ... PZT 36 ... Oscillator 37 ... Modulator 39 ... Mirror 41a, 41e ... Motor 44 ... Interference light detector 48 ... Analyzer 49 ... Half mirror 51, 55 ... Mirror 53 ... PD 54 ... X-stage 56 ... Stepping motor

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[Procedure amendment]

[Submission date] March 12, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction content]

The light reflected by the hollow organ 85 passes through the prism 96, the lens 94 and the SELFOC lens 93 and is incident on the front end surface of the optical fiber 92.
The light is incident on the front end surface of the optical fiber 33a from the rear end surface.
Almost half of this light is moved to the optical fiber 33b by the coupler 34, and is guided to the interference light detection unit side together with the reference light reflected by the mirror 45 arranged facing the tip end surface of the optical fiber 33b.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0077

[Correction method] Change

[Correction content]

[0077]

As described above, according to the present invention, it is possible to simultaneously display a surface observation image of a subject with visible light or the like and a tomographic image with low coherence light, so that the lesion tissue is deep. It is possible to easily determine the range existing in the vertical direction.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an optical tomographic imaging apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a scanning unit.

FIG. 3 is an explanatory diagram showing that a tomographic image is displayed on a monitor together with an image of an affected area.

FIG. 4 is a diagram showing a TV probe according to a modification of the first embodiment.

FIG. 5 is a characteristic diagram showing spectral characteristics of a dichroic mirror.

FIG. 6 is a diagram showing that an index corresponding to a range in which a tomographic image is obtained is displayed on a monitor screen.

Figure 7 is a cross-sectional view of the distal end of the TV probe according to a modification of FIG.

FIG. 8 is a configuration diagram showing an optical tomographic imaging apparatus according to a second embodiment of the present invention.

FIG. 9 is a configuration diagram showing an optical tomographic imaging apparatus according to a third embodiment of the present invention.

FIG. 10 is a diagram showing an image display example on a monitor.

FIG. 11 is a view showing that the distal end surface of the insertion portion can be observed while being pressed against the tissue in the body cavity.

FIG. 12 is a configuration diagram showing an optical tomographic imaging apparatus according to a fourth embodiment of the present invention.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Correction target item name] Figure 9

[Correction method] Change

[Correction content]

[Figure 9]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kuniaki Kamami 2-43-2, Hatagaya, Shibuya-ku, Tokyo Within Olympus Optical Co., Ltd. (72) Inventor Oka ▲ saki ▼ 2nd birth Hatagaya, Shibuya-ku, Tokyo 43-2 Olympus Optical Co., Ltd. (72) Inventor Tetsumaru Kubota 2-chome, Hatagaya, Shibuya-ku, Tokyo 43-2 Olympus Optical Co., Ltd. (72) Inventor Koji Yasunaga 2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industry Co., Ltd. 43-72 (72) Inventor Atsushi Osawa Hatagaya, Shibuya-ku, Tokyo 2-43 Olympus Optical Co., Ltd. (72) Inventor Kaiji Ohashi Hatagaya, Shibuya-ku, Tokyo 2-43-2 Olympus Optical Co., Ltd. (72) Inventor Yoshinao Daimei 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olin Scan Optical Industry Co., Ltd. in

Claims (1)

[Claims] 1. An illumination light emitting means for emitting illumination light, and an objective optical system for forming an image of the surface of a subject illuminated with the illumination light.
An image pickup unit including an image pickup device that photoelectrically converts an image based on the objective optical system, a low coherence light generation unit that generates low coherence light, and guides the low coherence light into the image pickup unit. A light guide member that emits the low coherence light from the end face on the distal end side to the subject side in the imaging means, and guides the reflected light reflected on the subject side; The reflected light and the reference light generated from the low coherence light are caused to interfere with each other, and an interference light extracting means for extracting an interference signal corresponding to the interfered interference light, and an optical path length on the reference light side or the reflected light side is set. Optical path length changing means for changing, signal processing means for performing signal processing on the interference signal, and constructing a tomographic image in the depth direction of the subject, a captured image captured by the image sensor and the tomographic image And display means for displaying simultaneously. Tomographic imaging apparatus.