JP2519272B2 - Endoscope magnetic detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an endoscope magnetic detection device using an optical fiber coated with a magnetostrictive material.

[Prior Art] Recently, by inserting an elongated insertion part into a living body,
BACKGROUND ART An endoscope that can observe the inside of a body cavity without making an incision has been widely used. Also, in the industrial field, an endoscope may be used when inspecting the inside of a chemical plant or the inside of a lumen.

By the way, for example, there is SQUID (superconductor quantum interferometer) as a means for detecting magnetic signals emitted from a living body. The research to be done is being conducted.

[Problems to be Solved by the Invention] However, this SQUID is a large-scale device, and therefore, the above-mentioned magnetic signal can be detected only from the body surface at the present time. Therefore, there are drawbacks such as low resolution for an inspection site. .

The applicant of the present invention has proposed an endoscope having NMR signal detecting means for NMR (nuclear magnetic resonance) in JP-A-59-88140.

Since this endoscope is generally used with a movable magnet that surrounds a living body, a large-scale device is required.

Fujii et al., "Optical Fiber Magnetic Field Sensor Utilizing Magnetostrictive Effect", Production Research Vol.38, No4, 1996, pp38-42 discloses a magnetic field detecting means utilizing magnetostrictive effect. However, it does not disclose a miniaturized product that can be used in such cases.

The present invention has been made in view of the above points, and an object thereof is to provide a small-sized endoscope magnetic detection device capable of detecting a weak magnetic signal.

[Means and Actions for Solving Problems] In the present invention, an optical fiber coated with a magnetostrictive material is disposed in the insertion portion of the endoscope to form a magnetic field detection sensor, and the detection means of the output light of this optical fiber is provided. By being provided, the optical fiber coated with the magnetostrictive material changes in transmission characteristics due to magnetism, so that it is small in size and weak magnetic detection can be performed.

EXAMPLES The present invention will be specifically described below with reference to the drawings.

1 to 5 relate to a first embodiment of the present invention, FIG. 1 is a schematic configuration diagram of the first embodiment, FIG. 2 is a sectional view showing a structure of a magnetic field sensor portion, and FIG. FIG. 4 is a configuration diagram of a magnetic field measuring unit in the first embodiment, FIG. 4 is a front view showing a distal end portion of an endoscope, and FIG. 5 is an explanatory diagram showing a usage example of the first embodiment.

As shown in FIG. 1, the endoscope magnetic detection device 1 of the first embodiment has a reference optical fiber (hereinafter referred to as a reference fiber) 4 for detecting magnetism in an insertion portion 3 of a fiberscope 2. An optical fiber (hereinafter, detection fiber) 5 is inserted.

A light guide 6 that transmits illumination light and an image guide 7 that transmits an optical image are inserted into the insertion portion 3 of the fiberscope 2. The light guide 6 and the image guide 7 are formed of a flexible fiber bundle. The light guide 6 inserted through the inside of the insertion portion 3 is further inserted through the inside of the light guide cable 9 extended to the outside from the operation portion 8 that is continuously provided at the rear end of the insertion portion 3 to illuminate the incident end thereof. It can be connected to the light source 11. Then, the white light focused and emitted from the light source lamp 12 of the light source 11 through the condenser lens 13 is transmitted, and the transmitted illumination light is emitted from the emission end face facing the distal end face of the insertion portion 3 toward the subject. The illuminated subject is imaged on the incident end face of the image guide 7 by the objective lens 14 arranged at the tip end, and an optical image is transmitted to the exit end face of the image guide 7 extending up to the vicinity of the eyepiece part 15. It can be observed with the naked eye through an eyepiece lens 16 arranged to face the exit end face.

By the way, the reference fiber 4 and the detection fiber 5 are folded back at the tip of the insertion portion 3 and inserted through the insertion portion 3. A magnetic field sensor section 21 is provided at a position near the tip of the insertion section 3 in the detection fiber 5.

The reference fiber 4 and the detection fiber 5 inserted through the insertion portion 3 are further inserted through the light guide cable 9 extended from the operation portion 8, and one end thereof is extended toward the laser device 22 side, The other end extends to the magnetic field measuring unit 23 side.

At the end faces of both fibers 4 and 5 extended to the side of the laser device 22, the laser light from this laser device is split by a beam splitter 24 into reflected light and transmitted light, and the lens 2
It is incident via 5,26. As this laser device 22, He
A Ne laser (in this case, the wavelength of the laser light is 632 nm) or a semiconductor laser can be used.

Then, the laser light incident from each one of the incident ends is transmitted through the reference fiber 4 and the detection fiber 5, and is output from the other end of the emitting end.
Convex lenses 27 and 28 are arranged facing the other ends, respectively. For example, the light on the detection fiber 5 side is reflected by a mirror 29 and merges with the light on the reference fiber 4 side that has passed through the convex lens 27 at the beam splitter 30. The combined light is the magnetic field measurement unit 23
The magnetic field is detected.

The reference fiber 4 and the detection fiber 5 are, for example, those having a diameter of 100 μm to 200 μm, and those made of the same material and having optical characteristics as uniform as possible are used. Both of these fibers 4 and 5 are formed of single mode fibers.

The structure of the magnetic field sensor portion 21 formed on the detection fiber 5 is shown in FIG.

As shown in FIG.
The magnetic field sensor unit 21 is formed by coating a magnetostrictive material 31 made of metal glass or the like for an appropriate length.

The detection fiber 5 portion coated with the magnetostrictive material 31 is
When a magnetic field is applied to the magnetostrictive material 31, the magnetostrictive material 31 is distorted by the magnetostrictive phenomenon, and the detection fiber 5 portion inside thereof is also expanded and contracted, and this expansion and contraction changes the optical path length of that portion. Since the light propagating through the fiber changes its phase, this phase change is caused to interfere with the reference light, and the magnetic field is detected by the change of the interference output.

FIG. 3 shows the configuration of the magnetic field measuring unit 23 that detects a magnetic field by changing the output of the interference light.

As shown in FIG. 3, the lights combined by the beam splitter 30 pass through the polarizing plate 32, and then are received by the photodiode 33 and photoelectrically converted. The photoelectrically converted electric signal is measured by the oscilloscope 34 and is also input to the digital memory 33 (via an amplifier and an A / D converter (not shown)), and is arithmetically processed by the arithmetic processing unit 36 to obtain a plotter.
It can be recorded on 37.

The tip of the fiberscope 2 with the fibers 4 and 5 inserted into the insertion portion 3 with a saw has the structure shown in FIG. 4, for example. The objective lens 14 is attached eccentrically slightly above the central axis of the insertion portion 3, and the light guide 6 is arranged in a ring shape on the outer periphery thereof. Further, a treatment instrument channel 38 is formed at a position near the lower portion. Then, for example, on the right side of the channel 38 facing the reference fiber 4
The detection fiber 5 is attached so as to be folded back. The detection fiber 5 is attached so as to be close to the outer peripheral surface.

The operation of the first embodiment thus configured will be described below with reference to the application example of FIG.

As shown in FIG. 5, when cancer 42 is present in the submucosal or surface of the body cavity wall 41 of the stomach, large intestine, etc., a magnetic substance-labeled antibody (hereinafter, magnetic substance-labeled antibody) 43 is first labeled in the blood of the patient. inject. The magnetic substance-labeled antibody 43 is composed of an antibody (tumor marker) that specifically binds to a tumor or a tumor-related substance (antigen-antibody reaction). Then, the magnetic substance-labeled antibody 43 binds to the cells of the cancer 42 from the artery 44 through the capillaries 45. still,
Reference numeral 46 is a vein returning via the capillary 45. Therefore, at this time, as shown in FIG. 5, by inserting the tip of the insertion portion 3 of the fiberscope 2 into the body cavity and detecting the magnetic amount of the magnetic substance, the presence or absence of the cancer lesion and its amount are as follows. Can be diagnosed.

The detection fiber 5 is provided at the distal end side portion of the insertion portion 3
Since the magnetostrictive material 31 covers the magnetostrictive material 31, when the magnetic field from the magnetic substance labeled antibody 43 is applied to the magnetostrictive material 31, the detection fiber 5 expands and contracts together with the strain of the magnetostrictive material 31. Due to this expansion and contraction, only the optical path length of the detection fiber 5 changes, and the light propagating through the detection fiber 5 undergoes a phase change. By interfering this light with the light of the reference fiber 4 which does not undergo the phase change, the output light is proportional to the magnetic field. This output light is a polarizing plate
Photoelectric conversion is performed on the photodiode 33 via 32, and the interference intensity waveform is obtained on the oscilloscope 34. The presence or absence and the amount of the magnetic substance-labeled antibody 43 can be detected from this waveform, which enables the diagnosis of the cancer 42. The photoelectric conversion output of the photodiode 33 is recorded on the plotter 37 via the digital memory 35 and the arithmetic processing unit 36. The first embodiment has the advantages that it can be inserted into a body cavity and used, and that it can approach a region to be inspected sufficiently close to it, so that a minute magnetic field can be detected and the resolution is high.

FIG. 6 shows the main part of the second embodiment of the present invention. The second embodiment is a magnetic field measuring unit 51 having a configuration different from that of the first embodiment.

The light passing through the polarizing plate 32 is received by the CCD 53 via the convex lens 52. This CCD53 is, for example, a two-dimensional CCD.
The signal photoelectrically converted by the CCD 53 is input to the camera control unit 54, subjected to signal processing, and displayed as an interference fringe on the monitor 55. Further, the output signal of the camera control unit 55 is input to the image processing circuit 57 via the A / D converter 56, the shift amount of the interference fringes is detected, and the strength of the magnetic field is detected by this information. The detection result is printed out on the printer 58. Others are the same as the configuration of the first embodiment. In the second embodiment, the voltage value is converted in the first embodiment, while the deviation of the interference fringes can be observed.

FIG. 7 shows the magnetic field sensor unit 61 in the third embodiment of the present invention.
Indicates.

In this embodiment, the detection fiber 5 is, for example, two Ni fibers.
The structure is such that the rods 62 and 63 are sandwiched between magnetostrictive materials. In this case, one Ni rod 62 is provided with a notch, the detection fiber 5 is put in this notch, and the detection fiber 5 is sandwiched between the Ni rods 62 and 63 by an epoxy resin 64 and fixed.

The third embodiment differs from the first embodiment only in the magnetic field sensor unit 61, and is similar in other respects.

 FIG. 8 shows the main part of the fourth embodiment of the present invention.

In the fourth embodiment, the solenoid coil 71 is provided in the insertion portion 3 in which the magnetic field sensor portion 21 is arranged in the first embodiment so as to cover the magnetic field sensor portion 21. Further, in the case of AC magnetic field measurement, the solenoid coil 71 has a solenoid coil energization unit to facilitate signal processing.
A DC current is applied from 72 to apply a DC bias magnetic field, and the output voltage of the photodiode 33 is detected by the synchronous detection by the lock-in amplifier 73. This embodiment is suitable for magnetic detection when an alternating magnetic field is generated. The observation optical system and the illumination optical system are omitted in FIG. In this case, an industrial one is preferable as the fiberscope (the basic structure is almost the same).

 FIG. 9 shows a fifth embodiment of the present invention.

In the fifth embodiment, an electronic scope 81 is used instead of the fiberscope 2 as the endoscope of the first embodiment. That is, in FIG. 1, the CCD 82 is arranged on the focal plane of the objective lens 14, and the image guide 7 and the eyepiece lens 16 are not provided.

The CCD 82 has a universal cord 83 inside the insertion portion 3
(Corresponding to the light guide cable 9 in FIG. 1) is connected to the video processor 84 by a signal cable inserted therethrough, and an endoscopic image picked up by the CCD 82 after signal processing can be color-displayed on the color monitor 85. I am trying.

The magnetic field sensor unit 86 of this embodiment has a structure shown in FIG. 10, for example.

For example, a thin Ni plate 91 having a fiber layer formed thereon is etched in a zigzag shape to form a fiber pattern 92 as shown in FIG. 10 (a) or (b), and then Ni fine powder 93 is used as an adhesive. The fiber pattern 92 is covered by mixing or the like as shown in FIG. 10 (b). Fig. 10 (a) shows the Ni
The figure before covering with fine powder is shown. It should be noted that both ends of this fiber pattern 92 are connected to the detection fibers 5 and 5, and the magnetic field sensor unit 8 is
Forming a six.

On the other hand, the reference fiber 4 is connected to a fiber pattern (the same pattern as that shown in FIG. 10A) formed on a substrate 94 made of a non-magnetic material other than a magnetostrictive material such as a Ni plate.

In this magnetic field sensor section 86, the magnetic field detection section can be made very long, and the fiber pattern 92 can be made thin, so expansion and contraction due to magnetostriction is easy, and it can be made compact and highly sensitive.

Although the magnetic field detecting portion (that is, the two fibers 4 and 5) is incorporated in the endoscope in each of the above-described embodiments, it may be formed in the shape of a plug that can be used through the channel. Conversely, the laser light source may be provided inside the endoscope.

By the way, the present invention can be used in the following cases other than the above-mentioned application examples.

1. Measurement of magnetocardiogram from transesophagus 2. Diagnosis of cancer of esophagus, small intestine, rectum, etc. 3. Laparoscopic measurement of liver cancer and iron accumulated in liver (abnormal iron accumulation is present.) 4. Diagnosis of cancer of the uterus and cervix 5. Diagnosis of cancer of the trachea and bronchus 6. Kinetic analysis of drugs administered to each main body 7. Determining the extent of cancer resection during surgery , 1 to 3, a strong magnetic field is applied to iron in a living body from outside the body, and after magnetized, the magnetic change of the magnetized iron is detected by using this device or a probe. Is also good.

In the above embodiments, the magnetic detection fiber and the reference fiber are used to perform magnetic detection, but in an endoscope made with a rigid insertion portion, only the magnetic detection fiber is used. The strength of the magnetic field can be known by detecting the loss of light caused by the distortion of the magnetic detection fiber with an optical power meter.

[Advantages of the Invention] As described above, according to the present invention, by disposing an optical fiber coated with a magnetostrictive material in an insertion portion of an endoscope or the like,
High-sensitivity magnetic measurement can be performed with a small-diameter endoscope.

[Brief description of drawings]

1 to 5 relate to a first embodiment of the present invention.
FIG. 1 is a schematic configuration diagram of the first embodiment, FIG. 2 is a sectional view showing a structure of a magnetic field sensor unit, FIG. 3 is a configuration diagram of a magnetic field measurement unit in the first embodiment, and FIG. 4 is an endoscope. FIG. 5 is a front view showing a tip portion, FIG. 5 is an explanatory view showing a usage example of the first embodiment, FIG. 6 is a configuration diagram of a magnetic field measuring portion in a second embodiment of the present invention, and FIG. FIG. 8 is a sectional view of a magnetic field sensor section in the third embodiment, FIG. 8 is a configuration diagram showing a main part of a fourth embodiment of the present invention, FIG. 9 is a configuration diagram of the fifth embodiment of the present invention, and FIG. It is explanatory drawing which shows the structure of the magnetic field sensor part in 5th Example. 1 ... Endoscope magnetic detection device 2 ... Fiberscope, 3 ... Insertion part 4 ... Reference fiber, 5 ... Detection fiber 21 ... Magnetic field sensor part, 22 ... Laser light source 23 ... Magnetic field measurement part, 32 …… Polarizer 33 …… Photodiode 34 …… Oscilloscope 35 …… Digital memory 36 …… Arithmetic processing unit, 37 …… Plotter

Claims (1)

(57) [Claims] 1. An optical fiber which can be disposed in an insertion portion of an endoscope and is coated with a magnetostrictive material, a light source device for supplying light to the optical fiber, and a detection means for detecting output light of the optical fiber. An endoscopic magnetism detection device characterized by being provided.