JP2002221486A - Optical tomograph imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a high precision tomograph image even if an angle of incidence to an optical fiber of a low interferential light and an angle of irradiation to a specimen is not vertical. SOLUTION: An imaging system includes a light guiding means having a plurality of optical fibers which guides the low interferential light to the specimen side and guides a reflected light. The low interferential light is guided in turn to a end face of a predetermined optical fibers in a vertical state to change an emitting position and the reflected light reflected from the specimen side is detected in order. The reflected light detected and a reference light generated by the low interferential light are caused to interfere and an interference signal corresponding to the interference light caused to interfere is extracted to perform processing of the interference signal. The tomograph image is formed in a depth direction of the specimen by an optical scanning means and a means to change an optical transmission time of the reference light side or the reflected light side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] 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 In recent years, when diagnosing a living tissue, an optical CT device capable of obtaining optical information inside the tissue has been proposed in addition to an imaging device for obtaining optical information on the surface state of the tissue. .

The optical CT apparatus uses picosecond pulses to detect information inside a living body and obtain a tomographic image. However, laser light sources that generate extremely short pulse light on the order of picosecond pulses are expensive, large, and cumbersome to handle.

[0004] Recently, an interference type OCT (optical coherence tomography) for obtaining a tomographic image of a subject using low coherence light is, for example, Science.
Vol. 254, 1178 (1991).

[0005]

The interference type OCT can be used for a tissue near the surface of a living body. However, in order to obtain information for diagnosing a tissue at an arbitrary site inside a body cavity, it is necessary to use the following method. Since there is no means for setting a site to be diagnosed, it becomes practically impossible.

If the angle of incidence of low-coherence light on the optical fiber or the angle of irradiation on the subject is not perpendicular, the transmission efficiency and the reflection efficiency decrease, and sufficient interference cannot be obtained, and a high-precision tomographic image is obtained. Could not get.

[0007] The present invention has been made in view of the above problems, and a high-precision tomographic image can be formed even when the incident angle of low-coherence light on an optical fiber or the irradiation angle on a subject is not vertical. It is an object to provide an optical tomographic imaging apparatus that can be obtained.

[0008]

In order to achieve the above object, a first optical tomographic imaging apparatus according to the present invention comprises: a low coherence light generating means for generating low coherence light; Light guiding means having a plurality of optical fibers for guiding the low-coherence light generated by the light to the subject side and guiding the reflected light reflected on the subject side, and a predetermined one of the plurality of optical fibers An optical scanning unit for sequentially guiding the low coherence light in a state perpendicular to the end face of the optical fiber to change the emission position, and sequentially detecting the reflected light reflected on the subject side, Interference light extraction means for causing interference between reflected light detected by the light scanning means and reference light generated from the low coherence light to extract an interference signal corresponding to the interfered interference light; and Light propagation time change that changes light propagation time on the light side And a 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 scanning means and the light propagation time changing means. .

In order to achieve the above object, a second optical tomographic imaging apparatus according to the present invention comprises a low coherence light generating means for generating low coherence light, and a low coherence light generated by the low coherence light generation means. A plurality of optical fibers for guiding the light to the subject side and for guiding the reflected light reflected on the subject side, and the optical axis of the low coherence light when coming into contact with the subject. An emission end face formed on each of the plurality of optical fibers so as to be perpendicular to the specimen, and the low interference with a predetermined optical fiber among the plurality of optical fibers of the light guide means. Scanning means for sequentially guiding the active light, changing the emission position, and sequentially detecting the reflected light reflected on the subject side, and the reflected light detected by the optical scanning means and the low coherence light. Interference with the reference light generated from Interference light extraction means for extracting an interference signal corresponding to interference light, light propagation time changing means for changing the light propagation time on the reference light side or the reflected light side, and signal processing on the interference signal; Signal processing means for constructing a tomographic image of the subject in the depth direction by the scanning means and the light propagation time changing means.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an optical tomographic imaging apparatus according to a first embodiment of the present invention. The optical tomographic imaging apparatus 1 according to the first embodiment includes an endoscope 2 capable of observing an arbitrary part in a body cavity, a light source device 3 that supplies illumination light to the endoscope 2, and an endoscope 2. A light guiding member for guiding light having low coherence is connected to the optical interference device 4 for performing optical tomographic imaging, and a monitor 5 as a display device for displaying an optical tomographic image by the optical interference device 4. Be composed.

The optical interference device 4 includes an interference unit 6 for detecting interference light between the measurement light and the reference light in order to generate an optical tomographic image using low coherence light, and an interference obtained by the interference unit 6. A signal processing unit 7 for processing an electric signal corresponding to light to generate a video signal corresponding to an optical tomographic image; this video signal is displayed on a monitor 5.

The endoscope 2 has an elongated and flexible insertion section 8, a wide operation section 9 provided at the rear end of the insertion section 8, and a rear end of the operation section 9. Eyepiece 11;
The light guide cable 12 extends from the side of the operation unit 9 to the outside.

The light guide 1 is provided in the insertion section 8, the operation section 9 and one of the light guide cables 12 branched in the middle.
3 is inserted, and the connector 14 at the proximal end thereof can be detachably attached to the light source device 3. In this mounted state, the white illumination light of, for example, a xenon lamp 15 inside the light source device 3 is condensed by the condenser lens 16 and the light guide 13
The illumination light is transmitted by the light guide 13, and is further emitted forward through the illumination lens 18 from the other end face fixed to the illumination window at the distal end portion 17 of the insertion section 8.

The illuminating light emitted through the illuminating lens 18 illuminates a site of interest 19 such as an affected part, which is illuminated, with an objective lens 21 attached to an observation window adjacent to the illuminating lens 18.
The optical image is formed on the focal plane. An image guide 22 having an image transmission function is provided at the position of the focal plane.
The image guide 22 transmits an optical image to the end face on the eyepiece section 11 side.

An eyepiece 23 is attached to the inside of the eyepiece window of the eyepiece 11 so as to face the end face of the image guide 22, and the surgeon brings the eyes closer to the eyepiece window to transmit the light through the eyepiece 23. The enlarged optical image can be observed.

The operating section 9 is provided with a bending operation mechanism (not shown), and by operating a bending operation knob,
The curved portion formed at the rear end of the distal end portion 17 can be bent in any direction, up and down, left and right, and the operator turns the observation window of the distal end portion 17 in a direction suitable for observing the site of interest 19 desired to be observed. be able to.

The endoscope 2 further includes a polarization maintaining fiber bundle 25 for transmitting low coherence light while maintaining the polarization plane.
Is inserted. That is, the polarization maintaining fiber bundle 25 is inserted through the insertion section 8, the operation section 9, and the light guide cable 12 branched on the way, and the connector 26 at the end of the light guide cable 12 is connected to the interference section 6 of the optical interference device 4.
It can be detachably attached to.

The polarization-maintaining fiber bundle 25 has, for example, a circular cross section at an intermediate portion, but has n polarization maintaining fibers arranged at both ends so that the cross section is linear. Also, as shown in FIG.
The array of 1,..., Fn is the fiber f1, at the other end.
.., Fn.

At a wavelength of, for example, 830 nm, an ultra-bright light emitting diode (hereinafter abbreviated as SLD) 31 as a light source having low coherence arranged in the interference section 6, for example, having a coherence length of about several tens to several thousand μm. Light is lens 32
a, the light is converted into linearly polarized light having a constant polarization plane through a polarizer 32b and a lens 32c, and is converted into a single mode optical fiber 33a.
From one end face and transmitted to the other end face.

The optical fiber 33a is a PANDA on the way.
The other single mode optical fiber 33b is connected to the coupler 34.
And optically coupled. Therefore, this coupler 34
It is split into two parts and transmitted. Optical fiber 33a
(From the coupler 34) is wound around a piezoelectric element such as a ceramic (abbreviated as PZT) 35 of lead zirconate.

The PZT 35 receives a drive signal from an oscillator 36 and forms a modulator 37 for modulating 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, and enters the mirror 41 of the scanner 39 via the lens 38 facing the distal end surface. This mirror surface 41 is the scanner 39
Is rotated so that the incident angle changes.

The light reflected by the mirror 41 passes through a cylindrical lens 42 and is held in the polarization maintaining fiber bundle 25.
, Fn. The light is transmitted by the polarization maintaining fiber bundle 25, sequentially emitted from the end faces of the fibers f1,..., Fn on the tip 17 side, and scans the region of interest 19 substantially linearly. The light reflected on the site of interest 19 side is transmitted by the polarization maintaining fiber bundle 25, and is incident on the distal end surface of the optical fiber 33a via the cylindrical lens 42, the mirror 41, and the lens 38.

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 33b also transmits the light reflected by the mirror 45 attached to the distal end surface thereof (the reference light obtained by splitting the light from the SLD 31 side by the coupler 34).
Lead to. That is, the light guided to the detection unit 44 side is transmitted to the polarization maintaining fiber bundle 25 side, and the measurement light reflected on the site of interest 19 side and the reference light reflected on the mirror 45 are mixed.

The mirror 4 in the optical fiber 33b
The optical path length at the portion of the optical fiber 33a wound for forming the modulator 37 and the optical path length by the polarization-maintaining fiber bundle 25 are substantially between the distal end fixed at 5 and the coupler 34. A compensation ring 46 having an optical path length for compensation is provided. 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 light component of the above-mentioned polarization plane is extracted by the analyzer 48, and then branched by the half mirror 49 into transmitted light and reflected light.

The reflected light is reflected by a mirror 51, and is condensed by a lens 52 (the light component transmitted by a half mirror 49), and is condensed by a silicon photodiode (abbreviated as Si-PD) 53 as a photodetector. Received. The transmitted light is reflected by a mirror 55 attached to the X-stage 54, and the light component reflected by the half mirror 49 is further reflected.
The light is condensed by the lens 52 and received by the Si-PD 53.

The X-stage 54 is moved in a direction facing the end face of the optical fiber 33b by, for example, a stepping motor 56 so that the optical path length on the reference light side can be changed.

The reference light reflected by the mirrors 45 and 55 is S
The optical path length until the light enters the i-PD 53 and the measurement light returning from a certain depth of the site of interest 19 via the polarization maintaining fiber bundle 25 are reflected by the mirror 51 and are reflected by the Si-PD 53.
In the case where the optical path length is almost equal to the optical path length before the light is incident, the interference light for the depth is detected. Therefore, the interference light for generating the optical tomographic image in the depth direction is obtained by changing the optical path length on the reference light side. Data is obtained.

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 be at least deviated from the interference range of the low coherence light. Are set so that interference does not occur in the half mirror 49 after the light is branched and transmitted to the transmitted light and the reflected light by the half mirror 49.

The signal photoelectrically converted by the Si-PD 53 is amplified by a preamplifier 57 and then input to a signal input terminal of a lock-in amplifier 58 of the signal processing unit 7. A drive signal of the oscillator 36 or a signal having the same phase as the drive signal of the oscillator 36 is input to the reference signal input terminal of the lock-in amplifier 58 as a reference signal, and a signal component having the same phase as the reference signal in the signal passed through the preamplifier 57 is extracted. It is detected and amplified.

The output of the lock-in amplifier 58 is input to a computer 59, and the polarization-maintaining fiber bundle 25
Is controlled to generate a video signal corresponding to the tomographic image from the signals obtained by the respective fibers fi (i = 1 to n) forming.

That is, a control signal is sent to the scanner 39 so that light is sequentially input from the fiber f1 to the fiber fn. While the light is sequentially scanned from the fiber f1 to the fiber fn, the signal input from the lock-in amplifier 58 is converted into a digital amount by an A / D converter and stored in, for example, an image memory (not shown).

When scanning is completed up to the fiber fn,
A control signal is sent to the stepping motor 56 and the mirror 55
Is controlled to move a little. The control signal is again sent to the scanner 39, and the signal input from the lock-in amplifier 58 is stored in the image memory while the light is sequentially scanned from the fiber f1 to the fiber fn. In this way, when the operation of storing the signal for the predetermined depth range in the image memory is completed, the signal stored in the image memory is transferred to the video processor 6 via a D / A converter (not shown).
Output to 0.

The optical path length until the light emitted from the end face of the optical fiber 33a is incident on the end face of each fiber fi is small at the center and large at both ends. If the correction is not made, the tomographic image will be distorted unless the correction is performed, and the computer 59 performs a process for performing the correction.

In the video processor 60, the computer 5
A standard video signal is generated by, for example, superimposing a synchronization signal on the signal input from 9, and output to the monitor 5. Monitor 5
Displays an input video signal on a monitor screen. The tomographic image 5a of the region of interest is displayed on this monitor screen.

According to the first embodiment, the endoscope 2 is inserted with the light guide member for guiding the light of low coherence, and guides the light of low coherence to the part of the body cavity where the diagnosis is desired. Can light,
A tomographic image for the site can be easily obtained. Therefore, even if the information obtained from the surface state of the part desired to be observed by the endoscope 2 is not sufficient, the information on the internal state can be obtained by obtaining this tomographic image, so that a more accurate diagnosis can be made. Information can be provided. In addition, it can be realized at a lower cost than when a picosecond pulse is used.

FIG. 2 shows the structure of a main part of a first modification of the first embodiment. In this modified example, the end of the polarization maintaining fiber bundle 25 on the connector 26 side is different. That is, in this modified example, the ends are arranged so as to form an arc, and the optical path lengths emitted from the distal end surface of the optical fiber 33a and reaching the ends of the fibers f1 to fn of the polarization maintaining fiber bundle 25 are the same. It is arranged so that it becomes.

In this modification, the light reflected by the mirror 41 is incident (guided) to each fiber fi without using the cylindrical lens 42. Mirror 4
1 is set so that the actual light reflection position is at the center of the arc. According to this modification, each fiber f
Since the respective optical path lengths when guided to i are equal,
There are merits such as that the distortion of the obtained tomographic image can be reduced or that the correction of the distortion can be omitted.

FIG. 3 shows a main part of a second modification of the first embodiment. In this modification, a linear scanning mechanism 61 is disposed so as to face the end face on the connector 26 side. Optical fiber 3
The distal end of 3a is fixed to the X-stage 62 by a fixing member 63. The X-stage 62 has a lens 3
The mirror 8 and the mirror 64 are also fixed, and the light emitted from the distal end face of the optical fiber 33a is reflected at right angles by the mirror 64 via the lens 38, and is incident on the fiber fi of the polarization maintaining fiber bundle 25 facing the fiber fi.

The X-stage 62 is a stepping motor 6
5, scanning is performed in the direction indicated by the arrow, that is, in the direction parallel to the end face of the polarization maintaining fiber bundle 25. Also in this case, the optical path length until the light is guided to the end face of each fiber fi can be made constant. Therefore,
It has the same effect as the first modification.

FIG. 4 shows a part of the distal end of the endoscope in a third modification of the first embodiment. The distal end of each fiber fi of the polarization maintaining fiber bundle 25 is fixed to a hole provided in the distal end body 66 constituting the distal end portion 17, and the SELFOC lens 67 is arranged in a line on the distal end surface of each fiber fi. I have. The observation window 21a and the illumination window 18a provided adjacent to the line-shaped selfoc lens 67 have an objective lens 21 and an illumination lens 18 respectively.
Is attached.

The SELFOC lens 67 efficiently guides light in the forward direction along its optical axis, and condenses the light incident from the forward direction, and efficiently guides the light to the end face of each fiber fi. I do. According to this modification, sensitivity and S / N can be improved.

FIG. 5 shows a part of the endoscope end side in a fourth modification of the first embodiment. In this modification, a circular through hole is formed in the distal end body 66 adjacent to the observation window 21a and the illumination window 18a, and a lens 69 is attached inside the cover glass 68, and an optical fiber is inserted inside the lens 69. fi is stored as shown in an enlarged view in FIG.

That is, as shown in FIG. 6, the optical fibers fi are stacked and arranged so that the positions in the vertical direction are slightly shifted from each other, and the resolution is improved as compared with the case where the optical fibers fi are not stacked and arranged in the vertical direction.

FIG. 7 shows a main part of an optical tomographic imaging apparatus 71 according to a second embodiment of the present invention. In the first embodiment, in addition to the normal illumination optical system and the observation optical system, a light guide member that guides light with low coherence is provided independently in the endoscope 2, but in this embodiment, the observation optical system is provided. And the insertion portion can be reduced in diameter.

The endoscope 72 of this device 71 has a polarization maintaining fiber bundle 25 embedded in a fiber bundle 22a that forms the image guide 22 (image guide). For example, as shown in FIG.
The fibers f1 to fn of the polarization maintaining fiber bundle 25 are embedded in a line so as to pass through the center of 2a.

The objective lens 21 is arranged facing the distal end surface of the image guide 22 in which the polarization maintaining fiber bundle 25 is embedded, and a cover glass 74 is arranged in front of the objective lens 21. In this embodiment, the light guide 13
Is branched into two in the insertion portion 8, and each end is fixed so as to be inclined so that illumination light can be emitted through the cover glass 74.

The polarization-maintaining fiber bundle 25 is separated from the image guide 22 by, for example, the operation unit 9 and inserted through, for example, a cable different from the light guide cable 12 (as shown in FIG. The connector 26 may be inserted at the distal end, and may be branched at the distal end).

The other configuration is the same as that described with reference to FIG. 1 or FIG. 2, so that the same components are denoted by the same reference numerals and description thereof will be omitted. In this embodiment, the polarization maintaining fiber bundle 25 is embedded in the image guide 22,
Since the observation optical system is shared, the diameter of the insertion section 8 can be reduced as compared with the case where the polarization maintaining fiber bundle 25 is provided independently of the image guide 22, and there is an advantage that the measurement position can be confirmed.

Since the illumination light is emitted through the common cover glass 74 and the light for observation or the like is taken in, the distal end surface of the insertion portion 8 is attached to the subject 75 as shown in FIG. Lighting and observation can be performed in a state of being in close contact. When used in a close contact state in this way, it is possible to prevent misalignment with the subject 75 during measurement, and to obtain a highly accurate optical tomographic image.

FIG. 10 shows a main part of an optical tomographic imaging apparatus 81 according to a third embodiment of the present invention. In this embodiment, a plurality of optical tomographic images having different scanning directions can be obtained.

In the endoscope 82 of this embodiment, in addition to a normal illumination optical system and an observation optical system, fiber bundles 25A and 25B for transmitting two low-coherence lights are inserted. In FIG. 17, two fiber arrays 83A and 83B are arranged, for example, in a cross shape as shown in FIG. The fiber at the center of the cross in FIG. 11 is commonly used.

The fiber bundles 25 A and 25 B are inserted through a cable 84 extending from the operation section 9, and their ends are connected to the interference section 85. Fiber bundle 25A,
The ends of 25B are arranged in an arc like the one described in FIG.

In other words, the two ends are arranged so as to face each other on a circle centered on the mirror 41, and the mirror 41 is rotated by a motor (not shown).
The low-coherence light from the optical fiber 33a is guided through the lens 38 to the fibers f1 to fn and f1 'to fn' at each end, and the light reflected on the subject side is transmitted to the optical fiber 33a. To light.

The interference unit 85 of this embodiment may have the same configuration as that of the first embodiment, or may have a configuration simply shown in FIG. In FIG. 10, the light of the SLD 31 is incident on one end face of the optical fiber 33a by the lens 32, passes through a coupler 34 partly branched to the other optical fiber 33b, and further passes through a modulator 37 formed of a PZT 35 or the like. The light is emitted from the front end surface to the mirror 41 side.

For example, in the state of the mirror 41 shown by the solid line in FIG. 10, light is guided toward the fiber bundle 25A, emitted from the fiber array 83A toward the subject in front, and part of the light reflected on the surface and inside is removed. The light is incident on the same fiber fi. This light is reflected by the mirror 41 and the coupler 34
Through the other optical fiber 33b, and is received by a photodetector 86 such as a Si-PD.

On the other hand, the light of the SLD 31 is branched to the other optical fiber 33b via the coupler 34, passes through the compensation ring 46, and is condensed by the lens 87 from the end face of the optical fiber 33b and emitted. This light is reflected by the mirror 45 and received by the photodetector 86 as reference light from the rear end face of the optical fiber 33b.

The mirror 45 is moved by a scanning mechanism (not shown) as shown by an arrow, and the optical path length on the reference light side is changed. When the optical path length of the measurement light returning through the endoscope 82 side almost coincides with the optical path length of the reference light side, it is detected by the detector 86 as interference light, and is output to the signal processing unit 7 shown in FIG. Signal processing is performed, and a tomographic image is displayed on the monitor 5. In this case, a tomographic image GA displayed on the left side of the monitor 5 as shown in FIG. 13 corresponding to the vertical scanning as shown by the solid line SA in FIG. 12, for example.

In the state of the mirror 41 shown by the dotted line in FIG. 10, the light guided to the fiber bundle 25B side, emitted from the fiber array 83B to the object side ahead, and part of the light reflected on the surface and inside is the same fiber. fi.

This light is reflected by the mirror 41, moves to the other optical fiber 33b via the coupler 34, and
The signal processing unit 7 shown in FIG.
The signal is output to the side, the signal is processed, and a tomographic image is displayed on a monitor. In this case, as shown by a dotted line SB in FIG. 12, the tomographic image GB is displayed on the right side of the monitor 5 as shown in FIG.

FIG. 14 shows a fiber support member 91 fixed to the distal end portion of an endoscope according to a modification of the third embodiment.
A through hole is formed at the distal end of the insertion portion, and a fiber support member 91 is fixed to the through hole with an adhesive or the like.

A large number of holes are formed in the fiber support member 91 along a cross, and the distal ends of the fibers fi of the fiber array 83A and the fibers fi 'of the fiber array 83B are inserted and fixed with an adhesive or the like. ing. A selfoc lens 92 is attached to the end face of each of the fibers fi and fi '.

FIG. 15 shows a probe 93 according to a fourth embodiment of the present invention. FIG.
FIG. 15B is a cross-sectional view taken along the line AA ′ of FIG. The probe 93 is a probe (including an observation window 94a and an illumination window 94b) that can be inserted into a channel 94c of a normal endoscope 94.

An optical fiber bundle 95 for guiding light having low coherence is inserted into the probe 93, and the tip of the fiber bundle 95 is fixed by an optical fiber array support member 96 attached to the tip of the probe 93. I have.

The optical fiber array support member 96 is shown in FIG.
As shown in (b), the tip of the fiber bundle 95 is inserted and fixed in a hole provided along a circular arc on the circular surface 96a having a constant porosity. Therefore, as shown in FIG. 15A, the distal end of the fiber bundle 95 is an optical fiber array 95a arranged on a curved line along an arc.

FIG. 16 shows the arrangement of the distal end surface of the optical fiber array 95a. Holes are provided in a direction perpendicular to the tangential direction of the curved surface of the optical fiber array support member 96 with the porosity δ, that is, in the normal direction, and each optical fiber of the fiber bundle 95 is inserted and fixed in each hole. Therefore, each optical fiber is oriented in a direction perpendicular to the tangential direction of the curved surface.

According to this embodiment, an optical tomographic image having a fan-shaped visual field can be obtained as shown in FIG. The dotted line in FIG. 17 is, for example, the field of view obtained by the first embodiment, and this embodiment has an advantage that a wider field of view can be obtained than in the above-described embodiments.

FIG. 18 shows a probe 93 'according to a first modification of the fourth embodiment. In this modification, in order to improve the resolution, the optical fiber arrays are stacked by shifting the vertical position little by little.

FIG. 19 shows an optical fiber array support member 96 'according to a second modification of the fourth embodiment. This modification has a structure in which a selfoc lens 97 is arranged in front of an optical fiber array.

FIG. 20 shows the distal end side of a probe 101 according to a fifth embodiment of the present invention, and FIG.
FIG. 20B is a sectional view taken along line BB ′ of FIG. In this embodiment, an optical tomographic image in a side viewing direction can be obtained. For example, the probe 93 shown in FIG.
When trying to obtain an optical tomographic image in the side viewing direction using
The distal end must be greatly curved (bent). In this case, it is difficult to bend the esophagus and the like. In such a case, the probe 101 is suitable for use.

An optical fiber bundle 102 for guiding light having low coherence is inserted into the probe 101, and the tip of the optical fiber bundle 102 has a light attached to an opening provided on a side surface of a tip member 103 of the probe 101. It is fixed by the fiber array support member 104.

The optical fiber array support member 104 has a curved surface 104a curved at a predetermined porosity ρ.
A number of holes are formed in the direction 04a in a direction parallel to the axis of the probe 101, the respective optical fibers of the optical fiber bundle 102 are inserted and fixed in the respective holes b, and an optical fiber array 105 is formed in a direction parallel to the axis of the probe 101. Have been.

The optical tomographic image obtained by this embodiment corresponds to a visual field that spreads in a fan shape with respect to the depth as shown in FIG. Also in this embodiment, a selfoc lens as shown in FIG. 19 may be arranged in front of the end face of the optical fiber array 105. Further, the optical fiber array 105 is not limited to the one having the wide-angle field of view along the curved surface, but may be the one arranged along a straight line to obtain an optical tomographic image in the side viewing direction.

FIG. 22 shows an optical tomographic imaging apparatus 111 according to a sixth embodiment of the present invention. The optical tomographic imaging apparatus 111 shown in FIG. 22 includes an elongated and flexible insertion section 112 inserted into the subject, emits light for tomographic image observation, and reflects reflected light from inside the subject. It comprises an interference unit 113 that receives light, a signal processing unit 114 that processes the output of the interference unit 113, and a monitor 115 that displays the video signal generated by the signal processing unit 115.

The insertion section 112 is constituted, for example, as an insertion section of an endoscope, and has a channel section 116 of the distal end section 116.
The illumination window 117, the observation window 118, the suction channel 119, etc. are formed in a.

A light distribution lens is mounted inside the illumination window 117, and a light guide 120 is provided at the rear end of the light distribution lens.
Are connected. The light guide 120 is inserted through the insertion portion 112 and connected to a light source device (not shown).
The illumination light from the light source device is transmitted to illuminate the observation site of the subject from the illumination window 117.

The observation window 118 has the objective lens 12
1 is provided, and a distal end surface of an image guide 122 is arranged at an image forming position of the objective lens 121. The image guide 122 is inserted through the insertion section 112, and has a rear end face facing an eyepiece in an eyepiece (not shown). Then, the optical image of the observation site formed by the objective lens 121 is guided by the image guide 122,
Visual observation is possible from the eyepiece.

The insertion section 112 has an optical fiber bundle 1 as a means for radially scanning light for tomographic image observation.
23, and this optical fiber bundle 123 is
A plurality of optical fibers 123a are arranged in an annular shape on the outer peripheral side of 12. As shown in FIGS. 22 and 23,
The distal end of the optical fiber 123a is disposed on the outer peripheral side of the distal end portion 116 so as to surround the channel portion 116a,
As shown in FIG. 24, the distal end surface is cut at, for example, 45 ° with respect to the fiber axis to form a tapered surface 123b.

Then, aluminum, silver, gold, or the like is vapor-deposited on the tapered surface 123b to form a mirror surface, and the mirror surface is arranged so as to be inward at the tip of the insertion portion 112. Is emitted to the side of the fiber axis, and the reflected light reflected from the inside of the subject is made incident in the fiber axis direction. A mirror 124 a of the galvanometer 124 is disposed inside the interference unit 113 so as to face the end of the optical fiber bundle 123. The galvanometer 124 is controlled by a control circuit 125.

That is, the mirror 124 is so arranged that the light emitted from the distal end face of the optical fiber 33a is sequentially guided to each optical fiber at the end of the optical fiber bundle 123 via the lens 38.
The swing angle of a is variably controlled. In this state, the light reflected on the subject side enters the distal end surface of the optical fiber 33a via the lens 38. Other configurations of the interference unit 113 are the same as those shown in FIG. 10, for example, and a description thereof will be omitted.

The output of the photodetector 86 of the interference unit 113 is input to the signal processing unit 114, where it is subjected to signal processing to generate a video signal corresponding to the optical tomographic image, and the monitor 115 displays the optical tomographic image.

Although the optical fiber 123a has a tapered surface 123b at the end, a prism may be arranged instead of the tapered surface 123b.
Instead, as shown in FIG. 25, an optical fiber 123 a ′ having a distal end portion 123 c bent outward from the insertion portion 112.
May be used to form the optical fiber bundle 123.

Next, observation of an optical tomographic image using the apparatus 111 will be described. For example, when observing an optical tomographic image of an affected part of a human body organ, first, the insertion unit 112 is inserted into the body cavity. Next, when the outer peripheral side of the distal end 116 reaches the affected part position, the light of the SLD 31 in the interference part 113 is reflected by the mirror 124a of the galvanometer 124, and the optical fiber bundle 12
3 is made to enter each optical fiber 123a.

The light incident on each optical fiber 123a is
The light is reflected by the tapered surface 123b at the tip and emitted to the side of the fiber axis, and the light is scanned radially outward from the optical fiber bundle 123. When the light applied to the affected part is reflected on the tissue surface and inside, the reflected light is transmitted from the optical fiber bundle 123 to the mirror 1 of the galvanometer 124.
The light is guided into the interference unit 113 through the light detection unit 86 through the internal lens 38 and the optical fibers 33a and 33b.
Is incident on.

The output of the photodetector 86 is sent to the signal processing unit 11
4, the image signal is converted into a video signal corresponding to the optical tomographic image of the observation site, and the optical tomographic image is displayed on the monitor 115. According to this embodiment, when observing a tomographic image by inserting the insertion section 112 into the subject, the outer peripheral side of the distal end portion 116 of the insertion section 112 can be observed without requiring a complicated bending operation of the insertion section 112. Since the optical scanning is performed radially from the insertion section 112 only by inserting the part up to the site, an optical tomographic image of a desired observation site can be easily obtained.

FIG. 26 shows an insertion portion according to a modification of the sixth embodiment. In this modified example, the optical fiber bundle 123 is provided not on the entire circumference of the distal end portion 116 but on only a part thereof, and light is transmitted and received in a fan shape to obtain an optical tomographic image.

FIG. 27 shows an optical tomographic imaging apparatus 161 according to the seventh embodiment of the present invention. This optical tomographic imaging apparatus 161 is an endoscope 1 capable of observing an arbitrary part in a body cavity.
62, a light source device 3 for supplying illumination light to the endoscope 162, and a light guide member for guiding low-coherence light provided in the endoscope 162 are connected, and light for performing optical tomographic imaging is provided. It comprises an interference device 164 and a monitor (not shown) for displaying an optical tomographic image by the light interference device 164.

The optical interference device 164 includes an interference unit 166 that detects interference light for generating an optical tomographic image using light having low coherence, and an electric signal corresponding to the interference light detected by the interference unit 166. To generate a video signal corresponding to the optical tomographic image.

The endoscope 162 is the same as the endoscope 2 shown in FIG.
The ends on the sides are inserted into holes formed along the circumference of the disk, and are fixed with an adhesive or the like.

The interference section 166 of this embodiment obtains an optical tomographic image with light of one wavelength in the embodiment of FIG. 1, but in this embodiment, the optical tomographic image is obtained with light of three wavelengths. You will get an image.

For this reason, the three SLDs 31-1, 31-2, and 31-3 have a light generating portion.
Light of each wavelength of 60 nm, 790 nm, and 840 nm is generated, and the optical fiber 3 is transmitted through a lens 32a, a polarizer 32b, a dichroic mirror 32d, and a lens 32c.
The light is guided to 3a.

The optical rod 1 on which the lens 38 and the gear 171 are attached so as to face the distal end face of the optical fiber 33a.
72 is disposed at one end, and the gear 171 is connected to the shaft of a motor 174 via an intermediate gear 173.
75 is engaged. When the motor 174 rotates, the end face of the optical rod 172 faces the end face of each of the optical fibers f1 to fn on the connector 26 side of the polarization maintaining fiber bundle 25, and the light on the optical fiber 33a is polarized. The light is guided to the holding fiber bundle 25 and the light from the polarization holding fiber bundle 25 is
The light is guided to the side 3a.

The motor 174 is supplied with a drive signal for rotationally driving by a two-axis driver 176. The two-axis driver 176 supplies a drive signal to the motor 56 of the X stage 54. The supply of drive signals to the motors 174, 56 is controlled by the computer 59.

The detecting section 177 for detecting the light emitted from the optical fiber 33b is also configured so as to be able to separate and detect light of three wavelengths. That is, the reflected light of the mirror 51 and the reflected light of the mirror 55 are mixed by the half mirror 49, selectively transmitted / reflected by the dichroic mirror 178 according to the wavelength of the light, and further transmitted through the analyzer 48 and the lens 52. The light is received by the Si-PDs 53-1, 53-2, 53-3, respectively.

Si-PDs 53-1, 53-2, 53-3
Are amplified by the preamplifier 57 and then input to the lock-in amplifier 58 of the signal processing unit 167. The lock-in amplifier 58 has three channels so as to be able to correspond to three inputs instead of one input in FIG. 1, and each channel is sequentially selected and operated in time division.

The other points are the same as those of the embodiment shown in FIG.
In this embodiment, there is a merit that an optical tomographic image can be obtained with light of three wavelengths. Further, the light can be sequentially guided to the optical fibers f1 to fn of the polarization maintaining fiber bundle 25 only by rotating the optical rod 172 by the motor 174. That is, it is easy to sequentially guide the light to the optical fibers f1 to fn.

By the way, when an organ such as the intestine is stapled with a stapler and then cut, if the tissue at the stapled portion is dead, there is a risk that the staple may fall off postoperatively. A mechanism may be provided so that whether alive or dead is known in advance by measurement. Stapler 1 equipped with this mechanism
31 is shown in FIG.

In this stapler device 131, a stapler 133 for stapling a luminal organ 132 such as an intestine, and an optical fiber bundle 134 provided in the stapler 133 are connected via a cable 135 and a connector 136 to obtain a tomographic image. Device 137 that performs signal processing of
And a computer 138 that is connected to the imaging device 137 and performs an arithmetic process for determining whether or not the tissue is necrotic.
And a display device 139 for displaying a tomographic image or a result of necrosis determination.

At the end of the stapler 133, a cartridge 142 provided with an anvil 141 as shown in an enlarged view in FIG. 29 is attached. The fiber array 134a is formed in the longitudinal direction of the stapled portion of the cartridge 142. FIG. 30 shows the surface to be stapled.

A fiber array 134a is formed adjacent to the cutter guide groove 144, and emits light for measuring whether or not the tissue at the cut portion is necrotic, and can guide reflected light. Further, staple forming grooves 145 for forming staples are provided on both sides of the cutter guide groove 144 and the fiber array 134a.

FIG. 31 shows the structure of the imaging device 137. This imaging device 137 is the interference unit 8 shown in FIG.
5 includes means for generating light of two wavelengths and means for detecting light of each wavelength.

The SLDs 31-1 and 31-2 emit light having different wavelengths, for example, 750 nm and 800 nm, respectively.
7. The light is guided to the optical fiber 33a via the lens 32c. The light guided to the optical fiber 33a is incident on the optical fiber end face of the polarization maintaining fiber bundle 134 on the connector 136 side via the lens 38 and the mirror 41 from the distal end. The end face of the optical fiber on the connector 136 side is formed in an arc shape as described with reference to FIG.

The light transmitted by the polarization-maintaining fiber bundle 134 and reflected by the body cavity organ 132 is transmitted again by the polarization-maintaining fiber bundle 134 in the opposite direction, and is guided to the distal end surface of the optical fiber 33a. Part of this light is guided to the other optical fiber 33 b by the coupler 34, emitted from the end face on the photodetector side, passes through the lens 148, the dichroic mirror 149, and the lens 150, and the photodetectors 86-1, 86-86
-2.

The outputs of the photodetectors 86-1 and 86-2 are amplified by the preamplifier 57 and then input to the lock-in amplifier 58. The signals detected by the lock-in amplifier 58 are input to the computer 59 via the A / D converter 151.

The computer 59 controls the rotation of the mirror 41 and the movement of the mirror 45 to obtain image data corresponding to the tomographic image. This image data is transferred to the computer 138 of FIG. 28, which performs an arithmetic operation to analyze the data obtained at the two wavelengths, and the data obtained from the tissue portion facing the fiber array 134a corresponds to necrosis. It is determined whether or not to do.

FIG. 32 shows light attenuation characteristics with respect to the wavelength of hemoglobin in blood. When hemoglobin has oxygen (b) and does not have oxygen (a), it is possible to determine whether necrosis has occurred, since the degree of extinction for the two wavelengths is different. In other words, when the hemoglobin has oxygen for light having a wavelength of 800 nm, that is, when hemoglobin has normal oxygen and does not have oxygen,
In other words, it shows almost the same dimming characteristics as a tissue that has died without circulating blood.

On the other hand, light having a wavelength of 750 nm has a characteristic that the degree of dimming (hereinafter referred to as OD) is smaller when hemoglobin has oxygen than when it does not. When hemoglobin has oxygen, the wavelength is 750.
The OD (800) for 800 nm light is larger than the OD (750) for nm light. That is, OD (750) <OD (800).

On the other hand, when hemoglobin has no oxygen, the reverse tendency is exhibited. That is, OD (750)> OD (800).

Therefore, by comparing the reflection intensity data obtained at the two wavelengths as described above, it is possible to easily determine whether hemoglobin has oxygen or not. Further, when three wavelengths and four wavelengths are used, Mb and cytochrome can be detected in addition to hemoglobin.

In the above embodiment, when the optical path length is changed, the optical path length is not limited to the one performed on the reference light side serving as a reference, and the optical path length on the measurement light side may be changed.

[0110]

As described above, according to the present invention, a high-precision tomographic image can be obtained even when the angle of incidence of low-coherence light on an optical fiber or the angle of irradiation on a subject is not vertical. An optical tomographic imaging apparatus capable of performing the above-described operations can be provided.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of a main part of a first modified example of the first embodiment.

FIG. 3 is a configuration diagram of a main part of a second modified example of the first embodiment.

FIG. 4 is a sectional view showing a distal end side of an endoscope in a third modified example of the first embodiment.

FIG. 5 is a view showing a cross section of the endoscope distal end side in a fourth modification of the first embodiment;

FIG. 6 is a diagram showing a state in which optical fibers are stacked.

FIG. 7 is a configuration diagram of a main part of an optical tomographic imaging apparatus according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a distal end surface of an image guide.

FIG. 9 is a diagram showing a state in which a distal end surface of an insertion section is brought into close contact with a subject.

FIG. 10 is a configuration diagram of a main part of an optical tomographic imaging apparatus 81 according to a third embodiment of the present invention.

FIG. 11 is a diagram showing a distal end surface of an endoscope insertion portion.

FIG. 12 is an explanatory view showing a surface scanned by an optical fiber array.

FIG. 13 is a view showing that two tomographic images are displayed on a monitor.

FIG. 14 is a perspective view showing a fiber support member fixed to a distal end portion of an endoscope in a modified example of the third embodiment.

FIG. 15 is a view showing a probe according to a fourth embodiment of the present invention.

FIG. 16 is an explanatory diagram showing an arrangement of the tip of an optical fiber.

FIG. 17 is a view showing a fan-shaped tomographic range obtained according to a fourth embodiment;

FIG. 18 is a diagram showing a distal end side of a probe according to a first modification of the fourth embodiment;

FIG. 19 is a diagram showing an optical fiber array support member according to a second modification of the fourth embodiment.

FIG. 20 is a front view showing a distal end side of a probe according to a fifth embodiment of the present invention.

FIG. 21 is a view showing a fan-shaped tomographic range obtained according to a fifth embodiment;

FIG. 22 is a configuration diagram showing an optical tomographic imaging apparatus according to a sixth embodiment of the present invention.

FIG. 23 is a view showing a state in which a plurality of optical fibers are annularly arranged on the outer periphery of the insertion portion.

FIG. 24 is a diagram showing that the distal end surface of the optical fiber is a tapered surface;

FIG. 25 is a diagram showing a distal end side of an optical fiber in a modification.

FIG. 26 is a diagram showing a state in which a plurality of optical fibers are provided around the outer circumference of the insertion section.

FIG. 27 is a configuration diagram showing an optical tomographic imaging apparatus according to a seventh embodiment of the present invention.

FIG. 28 is an overall configuration diagram of a stapling apparatus.

FIG. 29 is a diagram showing a state in which an optical fiber array is provided on the tip side of the stapler.

FIG. 30 is a diagram illustrating a configuration of a cut surface on the distal end side of the stapler.

FIG. 31 is a configuration diagram of an imaging apparatus.

FIG. 32 is a diagram showing a schematic dimming characteristic with respect to the wavelength of hemoglobin in blood.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical tomographic imaging device 2 ... Endoscope 3 ... Light source device 4 ... Optical interference device 5 ... Monitor 6 ... Interference part 7 ... Signal processing part 8 ... Insertion part 9 ... Operation part 11 ... Eyepiece part 12 ... Light guide cable DESCRIPTION OF SYMBOLS 13 ... Light guide 15 ... Xenon lamp 17 ... Tip part 21 ... Objective lens 22 ... Image guide 23 ... Eyepiece 25 ... Polarization holding fiber bundle 26 ... Connector 31 ... SLD 32b ... Polarizer 33a, 33b ... Fiber 34 ... Coupler 35 ... PZT 36 ... Oscillator 37 ... Modulator 39 ... Scanner 41 ... Mirror surface 42 ... Cylindrical lens 44 ... (Interference light) detector 45 ... Mirror 48 ... Analyzer 49 ... Half mirrors 51 and 55 ... Mirror 53 ... Si-PD 54 ... X-stage 56 ... Stepping motor 57 ... Preamplifier 58 ... Lock-in amplifier 59 ... Computer 60 ... video processor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuichi Takayama 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (72) Inventor Kuniaki Kamiaki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Within Olympus Optical Co., Ltd. (72) Inventor Oka ▲ zaki ▼ Tsugio Students 2-43-2, Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Tetsumaru Kubota 2, Hatagaya, Shibuya-ku, Tokyo Chome 43-2, Olympus Optical Co., Ltd. (72) Koji Yasunaga 2-43-2, Hatagaya, Shibuya-ku, Tokyo (72) Inventor Atsushi Osawa 2 Hatagaya, Shibuya-ku, Tokyo (43) Inventor Kazushi Ohashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Orin (72) Inventor Yoshinao Daiaki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. F-term (reference) 2G059 AA05 AA06 BB12 CC16 EE02 EE05 EE09 FF02 FF06 GG02 GG03 GG06 GG10 HH01 HH02 HH06 JJ07 JJ11 JJ12 JJ13 JJ17 JJ19 KK01 MM09 MM10 NN06

Claims (2)

[Claims] 1. A low coherence light generating means for generating low coherence light, and a low coherence light generated by the low coherence light generation means is guided to a subject side and reflected on the subject side. A light guiding unit having a plurality of optical fibers for guiding the reflected light, and sequentially guiding the low coherence light perpendicularly to an end face of a predetermined optical fiber among the plurality of optical fibers. An optical scanning unit for sequentially detecting the reflected light reflected on the subject side while changing the emission position; and interfering the reflected light detected by the optical scanning unit with 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 reference light side or the reflected light side; and signal processing on the interference signal. The optical scanning means and the optical transmission means. Optical tomographic imaging apparatus characterized by comprising a signal processing means for constructing a tomographic image in the depth direction of the subject by the time changing means. 2. A low coherence light generating means for generating low coherence light, and a low coherence light generated by the low coherence light generation means is guided to the subject side and is reflected on the subject side. A plurality of optical fibers for guiding the reflected light, the optical axis of the low coherence light when contacting the subject is perpendicular to the subject, so that each of the plurality of optical fibers A light guiding means having a formed light emitting end surface; and sequentially guiding the low coherence light to a predetermined optical fiber among a plurality of optical fibers of the light guiding means to change a light emitting position and a subject. Light scanning means for sequentially detecting the reflected light reflected on the side, and the reflected light detected by the light scanning means and the reference light generated from the low coherence light interfere with each other to correspond to the interfered interference light. Interference light extraction means for extracting an interference signal to be transmitted; Light propagation time changing means for changing the light propagation time on the side or the reflected light side, and performing signal processing on the interference signal, and the light scanning means and the light propagation time changing means in the depth direction of the subject An optical tomographic imaging apparatus, comprising: signal processing means for constructing an image.