JP3571689B2 - Optical tomographic imaging system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical tomographic imaging apparatus that obtains a tomographic image of a subject using low coherence light.
[0002]
[Prior art]
Conventionally, for the diagnosis of cervical cancer, the surface of the cervix is observed using a colposcope. The colposcope estimates the degree of invasion in the depth direction of the lesion from the morphology of the surface of the cervix, or performs a biopsy from the site that seems to be the most advanced, makes a judgment based on histological diagnosis, and decides a treatment policy. I was
[0003]
[Problems to be solved by the invention]
However, with the above method, the accuracy rate is low (affected by the proficiency of the doctor or the site of the biopsy, etc.), and there is a problem that there is a possibility of remaining after treatment due to transpiration or rounding with a laser. I do.
[0004]
In addition, usually, only one portion of tissue is collected by biopsy, and there is a possibility that a diseased portion cannot be reliably collected. If a wide range of tissue is collected in order to surely collect a lesion, a large number of biopsies or a wide range of resections with a scalpel or the like are required, and the patient suffers from increased pain.
[0005]
The present invention has been made in view of the above problems, and has as its object to provide an optical tomographic imaging apparatus capable of easily measuring the degree of infiltration of a lesion.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an optical tomographic imaging apparatus according to the present invention includes: an illumination light emitting unit that emits illumination light for illuminating an object; and a reflected light reflected on a surface of the object based on the illumination light. An objective optical system, an imaging unit having an imaging element that captures an image of the surface of the subject based on the illumination light, which is incident on the objective optical system, and a predetermined low coherence light for irradiating the subject. A low-coherence light generating unit that generates light, and guides the low-coherence light generated by the low-coherence light generation unit to irradiate the subject, and on the subject side based on the low-coherence light. A light guiding unit for guiding the reflected light, and an interference signal corresponding to the interfered interference light by causing the reflected light guided by the light guiding unit to interfere with the reference light generated from the low coherence light. Interference light extracting means for extracting the reference light; Or a light propagation time changing means for changing the light propagation time on the side of the reflected light guided by the light guiding means, and a light emission position scanning means for scanning a position where the low coherence light is emitted to the subject. Performing signal processing on the interference signal, signal processing means for constructing a tomographic image in the depth direction of the subject by the light propagation time changing means and the light emission position scanning means, and imaged by the image sensor. Display means for displaying an image; display Instructed by means range Emission position control means for controlling the emission position by the light emission position scanning means based on
[0007]
Thereby, the range of the lesion part can be easily known from the tomographic image.
[0008]
Therefore, a biopsy may not be required, and even if a biopsy is performed, the number of necessary biopsy sites is minimized, and the pain of the patient can be greatly reduced. In addition, the burden on the operator is reduced.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
Hereinafter, embodiments of the present invention will be described 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, FIG. 2 shows a configuration of a scanning unit, and FIG. , Indicating that a tomographic image is displayed.
[0010]
The optical tomographic imaging apparatus 1 according to the first embodiment includes a colposcope 2 capable of observing an affected part 3 such as a cervical cancer in a living body, and a light having low coherence for performing optical tomographic imaging, and the colposcope 2 side. Optical tomographic image observation device 4 for guiding the reflected light from the affected part 3 side as the measurement light to interfere with the reference light, and signal processing for the interference signal detected by the optical tomographic image observation device 4 And a signal processing device 6 for performing signal processing and the like for the TV camera 5 attached to the colposcope 2 and a monitor 7 for displaying a video signal output from the signal processing device 6. The (obverse) observation image of the affected part 3 and the optical tomographic image obtained by the low coherence light obtained in the above are superimposed and displayed.
[0011]
The colposcope 2 is a binocular, and a common objective lens 11 having a large diameter is attached to a distal end of the lens barrel 8 in order to form an optical image of the diseased part 3 illuminated by illumination light (not shown). Opposing to the objective lens 11, a variable power lens 12a12b, beam splitters 13a and 13b, imaging lenses 14a and 14b, and eyepieces 15a and 15b are arranged on respective optical axes.
[0012]
The light split by the beam splitter 13a forms an image on a CCD (not shown) of the TV camera 5 via the imaging lens 16. The output signal of the TV camera 5 is input to a video signal processing circuit 17, where a video signal is generated and mixed by a superimposing circuit 18 with a video signal that has passed through an arithmetic unit 19 from the optical tomographic image observation apparatus 4 side. Is output to the monitor 7 and displayed on the monitor 7 as shown in FIG.
[0013]
The other beam splitter 13b receives light from the optical tomographic image observation device 4 through the scanning unit 21 and guides light reflected at the affected part 3 to the optical tomographic image observation device 4 through the beam splitter 13b. Light. The scanning unit 21 two-dimensionally scans low-coherence light by the two-axis control unit 22.
[0014]
An ultra-bright light emitting diode (hereinafter abbreviated as SLD) 31 as a light source that generates low coherence light is arranged in the optical tomographic image observation apparatus 4. The SLD 31 has a wavelength of, for example, 830 nm and a coherence length of, for example, about several tens to several thousand μm. This light is converted into linearly polarized light having a predetermined polarization plane through a lens 32a, a polarizer 32b, and a lens 32c. The light enters from one end face of the mode optical fiber 33a and is transmitted to the other end face (referred to as a tip face).
[0015]
This optical fiber 33a is optically coupled to the other single mode optical fiber 33b by a PANDA coupler 34 on the way. Therefore, the signal is branched and transmitted by the coupler 34. The distal end side (from the coupler 34) of the optical fiber 33a is wound around a piezoelectric element such as a ceramic (abbreviated as PZT) 35 of lead zirconate.
[0016]
The PZT 35 forms a modulator 37 to which a drive signal is applied from an oscillator 36 and modulates light transmitted 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 distal end surface of the optical fiber 33a to the scanning unit 21.
[0017]
As shown in FIG. 2, a condensing lens 38 is disposed in the scanning unit 21 so as to face the distal end surface of the optical fiber 33 a, and enters the mirror 39 via the condensing 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 two-axis control unit 22 as shown by the arrow Y1. Is rotated.
[0018]
Further, the first motor 41a and the first gear box 41b are supported by a support member 41c, and the support member 41c is an axis of a second gear box 41d disposed so as to be orthogonal to the axis of the first motor 41a. Attached to. The second gear box 41d is provided on a shaft of the second motor 41e.
[0019]
When the second motor 41e controlled by the two-axis control unit 22 is rotated, the mirror 39 is rotated as indicated by an arrow Y2. When the mirror 39 is rotated as indicated by arrows Y1 and Y2, the light that is two-dimensionally scanned toward the beam splitter 13b is guided, and the reflected light from the beam splitter 13b is transmitted to the distal end surface of the optical fiber 33a. To light.
[0020]
As shown in FIG. 1, the light guided to the beam splitter 13b side is emitted to the affected part 3 side through the variable power lens 12b and the objective lens 11, and scans the affected part 3 two-dimensionally. A part of the light reflected by the optical fiber 33a is guided to the distal end face of the optical fiber 33a via the beam splitter 13b.
[0021]
Almost half of this light is transferred to the optical fiber 33b by the coupler 34 and guided to the interference light detection unit 44. The optical fiber 33 b also transmits the light reflected by the mirror 45 attached to the distal end surface thereof (reference light obtained by splitting the light from the SLD 31 side by the coupler 34), and guides the light 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 the measurement light reflected by the affected part 3 and the reference light reflected by the mirror 45 are mixed.
[0022]
The optical path length of the optical fiber 33a wound by the modulator 37 between the distal end of the optical fiber 33b to which the mirror 45 is fixed and the coupler 34 or the optical path length reaching the affected part 3 is almost compensated. A compensation ring 46 is provided. The light emitted from the rear end face of the optical fiber 33b is converted into a parallel light flux by a lens 47, and the light component on the plane of polarization is extracted by an analyzer 48, and then split by a half mirror 49 into transmitted light and reflected light.
[0023]
The reflected light is reflected by a mirror 51, and is condensed by a lens 52 (the light component transmitted by the half mirror 49), and is received by a photodiode (abbreviated as PD) 53 as a photodetector.
The light transmitted through the half mirror 49 is reflected by a mirror 55 attached to the X-stage 54, and the light component (reflected by the half mirror 49) is collected by the lens 52 and received by the PD 53.
The X-stage 54 is moved in a direction X facing the end face of the optical fiber 33b by, for example, a stepping motor 56 so that the optical path length can be changed.
[0024]
When obtaining an optical tomographic image of the affected part 3, the optical path length until the light reflected by the mirrors 45 and 55 enters the PD 53 and the light returned from the affected part 3 through the optical fiber 33 a are reflected by the mirror 51. The optical path length is set so as to be almost equal to the optical path length until the light enters the PD 53.
[0025]
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.
[0026]
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 at least from the interference range of the low coherence light. When the light is mixed by the half mirror 49 after being split into transmitted light and reflected light by the mirror 49, interference is not caused.
[0027]
The signal photoelectrically converted by the PD 53 is input to a lock-in amplifier or the like (not shown) of the arithmetic unit 19 included in the signal processing device 6 with a drive signal of the oscillator 36 or a signal having the same phase as the reference signal together with the reference signal. Heterodyne detection is performed to extract a signal component having the same frequency as the reference signal in the signal, and a signal component having the same phase is extracted and further detected and amplified. After that, it is input to a computer unit (not shown) inside the arithmetic unit 19.
[0028]
Based on the coordinate data indicated by the mouse 57 and the magnification signal input from the magnification detection circuit 58, the computer unit converts the scope image G1 of the colposcope 2 displayed on the monitor 7 as shown in FIG. The coordinates of the range of the cursor K to be superimposed are calculated.
[0029]
The rotation amounts of the motors 41 a and 41 e of the scanning unit 21 are determined from the calculation results of the coordinates, and the rotation amount is driven via the two-axis control unit 22 to optically scan the area designated by the mouse 57. The signal obtained by the optical scanning is temporarily stored in an image memory (not shown). When a scanning image in a predetermined range in the depth direction is obtained by scanning the mirror 55 by rotation of the motor 56, the image data in the image memory is shown. The video signal corresponding to the optical tomographic image is output to the monitor 7 via the superimposing circuit 18 by a video signal processing unit which does not perform the processing.
[0030]
In this embodiment, when a video signal corresponding to the optical tomographic image is output from the arithmetic unit 19, the scope image G1 captured by the TV camera 5 is reduced, and as shown in FIG. Is displayed.
[0031]
According to this embodiment, the scope image G1 and the tomographic image G2 of the surface of the diseased part 3 such as the cervix can be displayed on the monitor 7 at the same time, so that the lesion site and the spread range of the lesion site in the depth direction can be displayed on the tomographic image G2. Can be grasped from. Therefore, it is possible to determine the range of the lesion in the depth direction without having to perform the biopsy many times. Therefore, the pain of the patient can be reduced (since it is not necessary to perform multiple biopsies), and the burden can be reduced because the operator does not need to perform multiple biopsies.
[0032]
Further, since the light is guided to the colposcope 2 via the scanning unit 21 by the optical fiber 33a, the diameter of the lens barrel 8 can be reduced. Further, since the configuration is such that light is guided to the beam splitter 13b, a unitized configuration detachable from the beam splitter 13b can also be employed. With this configuration, when the colposcope 2 is used, the unit for obtaining the optical tomographic image can be selectively used or not used as necessary.
[0033]
FIG. 4 shows a TV probe 61 according to a modification of the first embodiment. In this modification, a TV probe 61 incorporating a CCD 62 is used instead of the colposcope 2 of FIG.
[0034]
In the TV probe 61, an objective lens 64, a variable power lens 65, a dichroic mirror 66, an imaging lens 67, and a CCD 62 are sequentially arranged on a cylindrical probe body 63, and a signal of the CCD 62 is input to the video signal processing circuit 17. Further, the scanning unit 21 is mounted on the reflection optical path side of the dichroic mirror 66 so as to guide the light of the optical fiber 33a to the dichroic mirror 66 and to guide the light from the dichroic mirror 66 to the optical fiber 33a. It has become.
[0035]
As shown in FIG. 5, the dichroic mirror 66 has a reflectance intensity with respect to the wavelength that reflects almost 100% of the light in the near infrared region from near the boundary wavelength between the visible region and the near infrared region, and the light in the visible region. Is used which has a characteristic of transmitting almost 100%. The wavelength of the SLD 31 is set within the near-infrared region, is always reflected by the dichroic mirror 66, and does not adversely affect the CCD 62 that captures light in the visible region.
[0036]
That is, the light from the optical fiber 33a is reflected by the dichroic mirror 66, is guided to the objective lens 64 side, and the reflected light of the SLD 31 returning to the dichroic mirror 66 from the objective lens 64 side is reflected by the dichroic mirror 66, and is reflected by the optical fiber 33a. The light is guided to the side. On the other hand, light in the visible region passes through the dichroic mirror 66 and forms an image on the CCD 62.
[0037]
Other configurations are the same as those of the first embodiment. In this modification, the image displayed on the monitor 7 is observed without having the observation optical system with the naked eye in the colposcope 2 in the first embodiment. FIG. 6 shows an image G captured by the CCD 62 and displayed on the monitor 7. A tomographic image can be observed on the monitor 7 only at a predetermined site (in this modified example, the center index S).
[0038]
Therefore, the surgeon moves and sets the TV probe 61 so that the part 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 two-axis controller 21.
[0039]
As shown in FIG. 7, a ring-shaped rubber 69 is attached in front of the objective lens 64 in FIG. 4, and the tip of the probe is pressed against a contactable part such as the cervix to obtain an optical tomographic image. You may do it.
[0040]
FIG. 8 shows an optical tomographic imaging apparatus 71 according to the second embodiment of the present invention. The optical tomographic imaging apparatus 71 according to the second embodiment includes an endoscope 72 capable of observing an arbitrary part in a body cavity, a light source device 73 that supplies illumination light to the endoscope 72, and an endoscope 72. The light guide member for guiding the light having low coherence is connected, and 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 are provided. Be composed.
[0041]
The optical interference device 74 obtains an electrical signal corresponding to the interference light for generating an optical tomographic image using low-interference light, and performs signal processing on the electrical signal of the optical interference unit 76. The signal processing unit 77 generates a video signal corresponding to the optical tomographic image. The video signal is displayed on a monitor 75.
[0042]
The endoscope 72 has an elongated and flexible insertion section 78 and a wide operation section 79 provided at the rear end of the insertion section 78. The cable is extended.
[0043]
A light guide 81 is inserted into the insertion portion 78, and a connector provided at an end of the light guide 81 on the cable side can be detachably attached to the light source device 73. By mounting, the white illumination light of, for example, a xenon lamp 82 inside the light source device 73 is condensed by the condenser lens 83 and supplied to the end of the light guide 81, and this illumination light is transmitted by the light guide 81 and inserted into the insertion section. The light is emitted to the side of the insertion portion 78 from the other end face fixed to the illumination window provided on the side of the distal end portion 84 of the insertion portion 78.
[0044]
The site of interest such as the luminal organ 85 illuminated by the illumination light emitted from the side-view illumination window is converted into an optical image by an objective lens 86 attached to the side-view observation window adjacent to the illumination window. Tied to A CCD 87 is arranged at the position of the focal plane, and photoelectrically converts the optical image.
[0045]
The CCD 87 reads out the photoelectrically converted signal by applying a CCD drive signal from a CCD drive circuit 88, and a video processor (hereinafter referred to as VP) as a video signal processing means via a video signal line 89. 90 is input.
[0046]
The output signal of the VP 90 is output to the monitor 75 via the superimpose circuit 91, and displays the endoscope image captured by the CCD 87.
[0047]
The operating section 79 is provided with a bending operation mechanism (not shown). By operating the bending operation knob, the bending section formed at the rear end of the distal end portion 84 can be bent in any direction, up, down, left, or right. It has become.
An optical fiber 92 for transmitting light with low coherence is inserted through the endoscope 72.
[0048]
The distal end of the optical fiber 92 is fixed on the central axis of the distal end portion 84, and a gradient index lens (hereinafter, referred to as a SELFOC lens) 93 is attached to the distal end surface. The rear end side of the optical fiber 92 is connected to the distal end surface of the optical fiber 33a of the optical interference unit 76, and the light of the SLD 31 is guided through the optical fiber 33a.
[0049]
The light of the SLD 31 enters from 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 optically coupled to the other single mode optical fiber 33b by a coupler 34 on the way. Therefore, the signal is branched and transmitted by the coupler 34. The distal end side (from the coupler 34) of the optical fiber 33a is wound around a piezoelectric element such as PZT35.
[0050]
The PZT 35 forms a modulator 37 to which a drive signal is applied from an oscillator 36 and modulates light transmitted by vibrating the optical fiber 33a. The modulated light is emitted from the distal end surface of the optical fiber 33a, is incident on the optical fiber 92 in contact with the distal end surface, is transmitted to the end surface on the distal end portion 84 side, and is emitted from this end surface through the selfoc lens 93. .
[0051]
The beam is converted into a parallel beam by a lens 94 arranged to face the SELFOC lens 93, reflected at right angles on the slope of a prism 96 attached to the gear 95, and emitted to the side of the insertion section 78. The gear 95 has an opening at a central portion so as to allow light to pass therethrough. The gear 95 meshes with a gear 97a attached to the rotation shaft of the motor 97.
[0052]
Therefore, when the motor 97 rotates, the prism 96 is rotated, and the light guided by the optical fiber 92 is emitted radially around the central axis of the insertion section 78.
[0053]
The motor 97 is fixed to a motor fixing base 98 having a rack formed on the back surface. This rack meshes with a pinion gear 99a attached to the rotation shaft of the motor 99.
[0054]
When the motor 99 rotates, the rack moves, and the motor 97 fixed to the motor fixing base 98, the gear 97a attached to the rotation shaft thereof, and the gear 95 maintaining the meshing state with the gear 97a interlock with the insertion portion. It moves in the axial direction 78, that is, in the longitudinal direction.
The rotation amounts of these motors 97 and 99 are controlled by a position control device 101 in a signal processing unit 77.
[0055]
The light reflected by the luminal organ 85 passes through the prism 96, the lens 94, and the selfoc lens 93 and is incident on the distal end surface of the optical fiber 92, and from the rear end surface of the optical fiber 92 is incident on the distal end surface of the optical fiber 33a. Is done. Almost half of this light is transferred 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 opposite to the distal end surface of the optical fiber 33b.
[0056]
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 unit. However, in this embodiment, the optical path length changing mechanism is provided on the distal end surface of the optical fiber 33b.
[0057]
That is, the mirror 45 in the embodiment of FIG. 1 is attached to the X-stage 54, and is moved by the motor 56 in a direction in which the optical path length of the reference light is changed, so that the optical path length is changed. Further, a lens 45a is disposed between the distal end surface of the optical fiber 33b and the mirror 45. The rotation of the motor 56 is controlled by the position control device 101.
[0058]
Light emitted from the rear end face of the optical fiber 33b is received by the PD 53 via the lens 52.
The signal photoelectrically converted by the PD 53 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. The reference signal input terminal of the lock-in amplifier 103 receives a reference signal from the oscillator 36, and performs heterodyne detection and amplification.
[0059]
The output of the lock-in amplifier 103 is input to a computer 105 via a digital voltmeter (hereinafter abbreviated as DVM) 104, and converts image data corresponding to a tomographic image from a signal obtained by light guided by the optical fiber 92. Performs control for generation.
[0060]
That is, a control signal is sent to the position control device 101 to control the amount of rotation of the motors 97 and 99, and to control the change in the optical path length due to the scanning of the light beam and the rotation control of the motor 56. When scanning the light beam and changing the optical path length, the signal obtained from the PD 53 is stored in the temporary image memory.
[0061]
For example, when one frame of image data is obtained, the image data is output to the VP 106, which is converted into a video signal, output to the monitor 75 via the superimpose circuit 91, and superimposed on the image of the CCD 87 to generate light. The tomographic image is displayed.
[0062]
When the motor 99 is rotated to move the prism 96 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. , So as to compensate for the change in the optical path length. With this control, image distortion due to a change in the optical path length is corrected.
According to this embodiment, there is an advantage that a three-dimensional tomographic image can be obtained while having the effects of the first embodiment.
[0063]
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 part in a body cavity, a light source device 73 that supplies illumination light to the endoscope 112, and an endoscope 112. A light guiding member for guiding light having low coherence is connected, and an optical interference device 114 for generating light for optical tomographic imaging and detecting interference light is provided. The signal processing unit 115 performs signal processing such as generation of a video signal corresponding to an image, and a monitor 116 as a display device that displays a video signal output from the signal processing unit 115.
[0064]
In the third embodiment, a dichroic mirror 117 is used to obtain a tomographic image of a living tissue 118 in an endoscope observation field of view.
[0065]
As in the second embodiment, the endoscope 112 has a light guide 81 inserted through the insertion portion 78 to transmit the illumination light of the lamp 82 of the light source device 73 and to illuminate the endoscope 112 from the distal end surface fixed to the distal end portion 84. -Illuminate the front living tissue 118 side via the glass plate 119 attached to the observation window. In this embodiment, the distal end side of the light guide 81 is configured to be branched into two.
[0066]
An objective lens 86 is arranged inside the glass plate 119 and forms an image on the CCD 87. The CCD 87 is driven by a CCD drive circuit 88, and the photoelectrically converted signal is input to a VP 90 in a signal processing unit 115 via a video signal line 89, and a video signal output from the VP 90 is output via a superimpose circuit 91. 10, an (endoscope) image of the living tissue 118 is displayed on the left side of the monitor 116 as shown in FIG.
[0067]
A dichroic mirror 117 is disposed between the objective lens 86 and the CCD 87, and is inclined by 45 ° with respect to the optical axis of the objective lens 86. The dichroic mirror 117 has characteristics as shown in FIG. 5, and transmits light in a visible region and reflects light in a near-infrared region. The prism 121 is arranged on the reflection optical path of the dichroic mirror 117.
[0068]
The prism 121 is attached to a movable base 122 having a rack formed on the back surface. The distal end of the optical fiber 92 is attached to the movable base 122 with an optical fiber fixing member, and the light emitted from the distal end 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 distal end surface of the optical fiber 92.
[0069]
The rack of the movable table 122 meshes with a pinion gear 125 attached to a tip of a shaft 124 connected to a rotation shaft of a stepping motor 123 housed in the operation unit 79, for example. 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.
[0070]
For example, when the movable base 122 is moved backward from the state shown in FIG. 9, the prism 121 is also moved backward, so that the light reflected by the prism 121 is guided as shown by a dotted line. Therefore, by moving the prism 121, light is scanned in the vertical direction on the living tissue 118 side, and a tomographic image corresponding to this scanning direction can be obtained.
[0071]
The rear end of the optical fiber 92 is connected to the front end surface of the optical fiber 33a of the optical interference device 114, guides the low coherence light from the SLD 31 to the optical fiber 92 side, and reflects the light reflected from the optical fiber 92 side. To the optical fiber 33a side.
[0072]
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 input to the computer 126 in the signal processing unit 115.
[0073]
The computer 126 controls the rotation of the stepping motor 123 and the rotation of the motor 56. Further, by performing processing for generating a video signal corresponding to the tomographic image and outputting the signal to the superimpose circuit 91, the tomographic image is simultaneously displayed on the monitor 116 adjacent to the endoscope image as shown in FIG. Is done.
[0074]
In addition, the computer 126 displays a cursor 128 indicating a region where a tomographic image is measured in the endoscope image as shown in FIG. With this display, the region where the tomographic image can be obtained can be known on the observation image, which is convenient for diagnosis. The cursor 128 can be deleted 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.
[0075]
In this embodiment, a glass plate 119 that emits visible illumination light and captures visible observation light is provided on the distal end surface of the endoscope 112, and the distal end surface of the insertion section 78 is attached to the stomach inner wall 129 as shown in FIG. Thus, an observation image can be obtained in a state where the observation image is pressed against the tissue in the body cavity.
[0076]
In addition, in the state of being pressed against the tissue in the body cavity, low-coherence light for obtaining an optical tomographic image is emitted to the tissue in the body cavity through the glass plate 119, and the reflected light in the tissue in the body cavity can be captured. Thus, it is possible to obtain a tomographic image of the central portion of the tissue in the body cavity within the visible observation visual field. By this close contact, blurring that occurs when the organ is moving or when the tip of the insertion section 78 fluctuates can be prevented, and a clear observation image and tomographic image without blurring can be obtained.
For this reason, in this embodiment, the observation system is set to a focal length suitable for observing the surface of the glass plate 119 approximately. The optical fiber 92 inserted through the endoscope 112 and the optical fiber 33a of the optical interference device 114 may be integrated.
[0077]
FIG. 12 shows an optical tomographic imaging apparatus 131 according to a fourth embodiment of the present invention. In the endoscope 132 of the fourth embodiment, the end surface of the image guide 133 is disposed on the photoelectric conversion surface of the CCD 87 in the endoscope 112 of FIG. 9, and the imaging lens 134 faces the rear end surface of the image guide 133. Is arranged so that the image transmitted by the image guide 133 is formed by the imaging lens 134 on the CCD 87 arranged at the image forming position.
[0078]
In this embodiment, the image guide 133 is inserted into the insertion section 78, the observation image is transmitted to the rear end face of the operation section 79, and the image is formed on the CCD 87 by the lens 134. The rest is the same as the configuration described in the third embodiment. In this embodiment, the endoscope image displayed on the monitor 116 is circular.
The operation and effects of this embodiment are almost the same as those of the third embodiment.
When the optical path length is changed, the optical path length on the measurement light side may be changed without being limited to the reference light (reference light) side serving as a reference. When an image of the surface of a subject such as a living body is obtained, the image is not limited to an image using visible light, but may be an image of infrared light, ultraviolet light, or the like.
[0079]
【The invention's effect】
As described above, according to the present invention, it is possible to easily determine the range where the diseased tissue exists in the depth direction.
[Brief description of the 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 view showing that a tomographic image is displayed together with an image of an affected part on a monitor.
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 view showing that an index corresponding to a range in which a tomographic image can be obtained is displayed on a monitor screen.
FIG. 7 is a sectional view showing a distal end side of a TV probe in a modification 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 example of image display on a monitor.
FIG. 11 is a view showing that the distal end surface of the insertion portion can be observed in a state where the distal end surface is pressed against tissue in a 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]
1. Optical tomographic imaging device
2 ... Colposcope
3 ... affected area
4: Optical tomographic image observation device
5 ... TV camera
6 ... Signal processing device
7. Monitor
8 ... barrel
11 Objective lens
12a, 12b ... variable power lens
13a, 13b ... Beam splitter
15a, 15b ... eyepiece
17 ... Video signal processing circuit
18. Superimpose circuit
19 arithmetic unit
21 ... Scanning unit
22 ... 2-axis control unit
31 ... SLD
32b ... Polarizer
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

Claims (1)

Illumination light emitting means for emitting illumination light for illuminating the subject,
An objective optical system that receives reflected light reflected on the surface of the subject based on the illumination light,
Imaging means having an imaging element, which captures an image of the surface of the subject based on the illumination light, which is incident on the objective optical system,
Low coherence light generating means for generating a predetermined low coherence light for irradiating the subject,
A light guide that guides the low coherence light generated by the low coherence light generating means to irradiate the subject with the light and guides the reflected light reflected by the subject based on the low coherence light. Means,
Interfering the reflected light guided by the light guiding means and the reference light generated from the low coherence light, interference light extraction means for extracting an interference signal corresponding to the interfered interference light,
Light propagation time changing means for changing the light propagation time on the side of the reference light or the reflected light guided by the light guiding means,
Light emission position scanning means for scanning a position for emitting the low coherence light with respect to the subject,
Signal processing means for performing signal processing on the interference signal, and constructing a tomographic image in the depth direction of the subject by the light propagation time changing means and the light emission position scanning means,
Display means for displaying an image captured by the image sensor;
Emission position control means for controlling an emission position by the light emission position scanning means based on a range instructed by the display means,
An optical tomographic imaging apparatus comprising:

Images