JP2018161287A - Endoscope and medical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the position of an endoscope correctly.SOLUTION: A plurality of magnetic detection coils 50, 50are arranged within an insertion section 10M of a video scope 10, and magnetic fields are generated from a magnetic field generation device 40 comprising a plurality of magnetic field generation coils 40-40, such that induction currents are generated from the magnetic detection coils 50, 50. The magnetic detection coil 50is configured as an induction coil having a copper wire 80 wound around a core 70, with a tubular cover member 90 opening in both ends arranged around the core 70.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an endoscope apparatus provided with a scope (endoscope), or a medical instrument inserted into a body such as a catheter or a stent, and particularly relates to position detection when the endoscope or medical instrument is inserted into the body.

  In an endoscope apparatus, a flexible endoscope insertion portion is inserted into the body, an observation site such as a digestive organ is observed, and treatment and surgery are performed as necessary. Since the lumen shape such as the large intestine and the small intestine is a complicated and winding shape, it is difficult for the operator (operator) to grasp the insertion portion shape and the distal end portion position. Therefore, an endoscope operation support system that detects an endoscope insertion portion shape is used from the viewpoint of facilitating operation (see, for example, Patent Document 1).

  There, a plurality of coils are arranged at the distal end portion of the endoscope insertion portion, and the magnetic field generator is installed at a predetermined position such as near the medical bed. When an alternating magnetic field is transmitted from the antenna of the magnetic field generator, an induced current is generated in the coil of the endoscope insertion portion, and a magnetic detection signal (current signal) is generated.

  Then, by detecting the relative position of the coil based on the amplitude and phase information of the magnetic detection signal, the position and shape of the endoscope insertion portion in the body are displayed on the monitor. A coil used as a position sensor is composed of a coil in which a copper wire is wound around a core formed of a material having high magnetic permeability (see, for example, Patent Document 2).

JP 2006-209343 A JP 2003-90702 A

  Metal parts are used in the endoscope insertion portion, and the composition may change due to a change in stress during processing, resulting in a magnetic body. If a magnetic body exists around the coil, an unnecessary magnetic field not along the coil axis direction is generated, and noise is generated in the induced current generated in the coil. As a result, an incorrect relative position of the coil, that is, an endoscope position is calculated.

  Therefore, it is required to configure the coil so as to prevent the influence of noise due to unnecessary magnetic field generation.

  The endoscope of the present invention includes at least one coil and a high-permeability cylindrical cover member that covers around the coil axis direction of the coil. For example, the coil can be configured by a coil in which a winding is wound around a rod-shaped core having a higher permeability than air. On the other hand, the processor of the present invention is a processor that calculates an endoscope position by amplifying a current signal sent from an endoscope coil. On the other hand, a time division pulse signal for sequentially driving a plurality of magnetic field generating coils in time series is output.

  The cover member can be configured to extend along the coil axis direction so that noise due to magnetic field lines along a direction perpendicular to the coil axis does not occur. Further, the cover member can be configured to cover the coil as a whole. The cover member may be formed of the same material as the core. An insulating material may be interposed between the cover member and the coil.

  An endoscope system according to another aspect of the present invention includes an endoscope provided with at least one coil and a high-permeability cylindrical cover member that covers around the coil axial direction of the coil, and a plurality of magnetic field generating coils. Equipped with a magnetic field generator and a time-division pulse signal that sequentially drives multiple magnetic field generating coils in time series, and amplifies the magnetic detection signal sent from the endoscope to calculate the endoscope position Processor.

  A medical instrument according to another aspect of the present invention includes at least one coil and a high-permeability cylindrical cover member that covers around the coil axis direction of the coil.

  Thus, according to the present invention, the position of the endoscope can be detected appropriately.

It is a block diagram of the endoscope system in this embodiment. It is the figure which showed in time series the drive signal to a magnetic field generator, and the output signal of a magnetic detection coil accompanying it. It is a schematic sectional drawing of a magnetic detection coil.

  Below, the endoscope system which is this embodiment is demonstrated with reference to drawings.

  FIG. 1 is a block diagram of an endoscope system according to this embodiment.

  The endoscope system includes a video scope 10 and a processor 20 to which the video scope 10 is detachably connected. When an affected part is observed and treated, the insertion part 10M of the video scope 10 is inserted into the body. . The processor 20 is connected to a monitor 60 that displays an observation image and a magnetic field generator 40.

  Light emitted from a light source unit (not shown) provided in the processor 20 is guided to the distal end portion 10T of the video scope 10 by a light guide provided in the video scope 10, and is directed from the distal end portion 10T toward the subject. Is irradiated. The reflected light from the subject forms an image on an image sensor (not shown) provided at the tip 10T, thereby forming a subject image. The signal processing circuit 30 of the processor 20 generates a color image signal based on the pixel signal for one field / frame read from the image sensor. As a result, the observation image is displayed on the monitor 60.

  The signal processing circuit 30 executes image signal processing and controls the entire operation of the processor 20, and is configured by an FPGA or the like. The signal processing circuit 30 outputs a control signal to each circuit in the processor 20 based on an operation control program stored in advance in a ROM or the like.

In the insertion portion 10M of the video scope 10, a plurality of induction coils (hereinafter referred to as magnetic detection coils) 50 are arranged at a predetermined interval. Here, two magnetic detection coils 50 ₁ and 50 ₂ are illustrated. ing. Here, the magnetic detection coils 50 ₁ and 50 ₂ are arranged so that the coil axis directions are different from each other.

On the other hand, also in the magnetic field generator 40, a plurality of induction coils (hereinafter referred to as magnetic field generating coils) 40 are arranged. Here, the n magnetic field generating coils 40 ₁ , 40 ₂ ,... 40 _n are arranged so as to be separated from each other by a predetermined interval and have different coil axis directions. The signal processing circuit 30 via the coil driver 26 ₍₂₆ 1 ~ 26 _n), when outputting the divided pulse signal to the magnetic field generator 40.

When an induced current is generated in the magnetic detection coil 50 by the magnetic field generation by the magnetic field generator 40, the current signal is amplified in the amplifiers 22 (22 ₁ , 22 ₂ ) in the processor 20 and the A / D converter 24 (24 ₁ , 24 ₂ ), A / D conversion processing is performed. The signal processing circuit 30 calculates the relative positions of the sensor coils 50 ₁ and 50 ₂ based on the input signal. Then, a 3D image representing the shape of the insertion portion 10M in the body is generated and displayed together with the observation image in the monitor 60. A dedicated processor for position detection and shape display, and a dedicated monitor may be provided separately from the processor 20 of the endoscope apparatus.

FIG. 2 is a diagram showing in time series the drive signal to the magnetic field generator 40 and the output signal of the magnetic detection coil 50 associated therewith. By outputting a time-division pulse signal from the processor 20 to the magnetic field generator 40, each coil of the magnetic field generator 40 is driven in time series. In FIG. 2, the magnetic field generating coils 40 ₁ to 40 _n are represented as “Coil _{1 to} Coil _n ”.

During the endoscopic operation, the position of the scope insertion portion 10M in the body moves, and the positions of the magnetic detection coils 50 ₁ and 50 ₂ change accordingly. Therefore, the relative positions of the sensor coils 50 ₁ to 50 ₂ with respect to the magnetic field generating coils 40 ₁ to 40 _n of the magnetic field generating device 40 change, and the current signals generated in the magnetic detection coils 50 ₁ to 50 ₂ also change. 2, the pattern of the current signal generated in the sensor coil 50 ₁ is shown.

On the other hand, as described above, since the magnetic field generating coils 40 ₁ to 40 _n are arranged so that their fixed positions and coil axis directions are different from each other, the waveforms of current signals generated in the magnetic detection coils 50 ₁ and 50 ₂ are as follows. In addition to the change in position of the scope insertion portion 10M, the difference depends on the relative positional relationship with each of the magnetic field generating coils 40 ₁ to 40 _n . However, the relative positional relationship includes a relative distance and a relative angle in the coil axis direction.

The positions of the magnetic field generating coils 40 ₁ to 40 _n (including the coil axis direction) are determined so that the relative positions of the sensor coils 50 ₁ and 50 ₂ are uniquely determined by their output signal waveforms. Therefore, the relative positions of the magnetic detection coils 50 ₁ and 50 ₂ are obtained from the current signals generated in the magnetic detection coils 50 ₁ and 50 ₂ with respect to the time-division pulse signal.

Figure 3 is a schematic cross-sectional view of a magnetic detection coil 50 _1. Magnetic detection coil 50 ₂ also have the same configuration. In FIG. 1, which schematically depicts the construction of a magnetic detection coil 50 _1, differs from FIG.

Magnetic detection coil 50 ₁ is a high permeability with a core 70 of circular cross-section of the bar-like (columnar) are constructed as induction coils wound with copper wire 80 around the core 70, copper 80 It is wound around substantially the entire core 70. Here, the core 70 is formed of ferrite and is fixed by a support member (not shown).

Around the core 70, that is, around the magnetic detection coil 50 _1, cylindrical cover member 90 is arranged so as to cover around the coil axis direction X. The cover member 90 arranged coaxially with respect to the core 70 is open at both ends thereof and extends along the coil axis direction X, and covers a range in which the copper wire 80 of the core 70 is wound, that is, substantially the entire core 70. It has a surrounding axial length.

The cover member 90 is formed of a material having a high magnetic permeability, and is formed of the same ferrite as the core 70 here. The inner surface 90I of the cover member 90, an insulating material 85 such as an adhesive has been applied, the cover member 90 is attached to the coil 50 ₁ via an insulating material 85.

  By providing such a cover member 90, it is possible to prevent a current signal from being generated with respect to the generation of a magnetic field other than the direction of the coil axis as described below.

Metal member such as stainless provided in the magnetic detection coil 50 ₁ surrounding, machining, etc. by changing the composition stress during assembly, and may vary the magnetic. The magnetic substance present around the sensor coil 50 generates an unnecessary magnetic field (lines of magnetic force) in a direction different from the core axis direction X by the magnetic field generated by the magnetic field generator 40.

Magnetic detection coil 50 _1, one sensitive to the magnetic field lines passing through the coil axis direction X, perpendicular to the core axis X (hereinafter referred to as the axial direction Y) with respect to the low sensitivity. Therefore, as described above, in the magnetic detection coils 50 ₁ and 50 ₂ , an induced current is generated based on the relative positional relationship with the magnetic field generating coils 40 ₁ to 40 _n , so that a current signal is output depending on the position and the core axis direction. The level difference increases. Furthermore, since the output level is very small depending on the positions of the magnetic detection coils 50 ₁ and 50 ₂ (distance from the magnetism generating coil), it is necessary to increase the amplification factor of the amplifier 22 in the processor 20.

Therefore high gain, even a coil 50 ₁ is less sensitive to the axial direction Y, noise occurs in the current signal by the magnetic force lines generated by the sensor coil 50 ₁ around the magnetic body. In particular, noise due to magnetic field lines along the axial direction Y has an effect. This noise reduces the SN ratio of the output signal from the sensor coil 50 _1, so that the relative position of the sensor coil 50 ₁ is incorrectly calculated.

However, in the present embodiment, by providing the cover member 90 so as to cover the coil 50 _1, the direction other than the direction of the coil axis X, difficult especially field lines as the axial direction Y. That is, the cover member 90 functions as a magnetic shield. As a result, it becomes possible to current signal to the coil 50 ₁ relative to the magnetic field lines along the core axis direction X occurs, it is possible to properly calculate the relative position of the coil 50 _1.

  On the other hand, since the cover member 90 is arranged coaxially with the core 70, the sensitivity to the magnetic field lines along the coil axis direction X increases, and contributes to accurate position detection of the magnetic detection coil 50. In particular, since the cover member 90 is made of the same ferrite as the core 70, the magnetic flux can be easily collected, that is, the inductance can be increased.

As described above, according to the present embodiment, a plurality of magnetic detection coils 50 ₁ and 50 ₂ are arranged in the insertion portion 10M of the video scope 10, and a magnetic field generation device including a plurality of magnetic field generation coils 40 ₁ to 40 _n. A magnetic field is generated from 40, and an induced current is generated from the magnetic detection coils 50 ₁ and 50 ₂ . Magnetic detection coil 50 _1, while being configured as induction coils wound with copper wire 80 to the core 70, a tubular cover member 90 having both ends open is disposed around the core 70.

  The position of the cover member 90 may be fixed without using the insulating material 85. On the other hand, the cover member 90 may be made of a nonmagnetic material different from the core 70, and may be formed of a material other than ferrite having a higher permeability than air. Or you may comprise the magnetic detection coil 50 by an air-core coil.

  The present invention can also be applied to non-invasive medical devices other than scopes or invasive medical devices. For example, it can be used for detecting the position of a catheter, stent, marker, or the like.

DESCRIPTION OF SYMBOLS 10 Videoscope 20 Processor 40 Magnetic field generator 40n Magnetic field generating coil 50 Magnetic detection coil (coil)
70 core 80 copper wire (winding)
90 Cover member

Claims (10)

At least one coil;
An endoscope comprising: a high-permeability cylindrical cover member that covers the coil in the coil axis direction.   The endoscope according to claim 1, wherein the cover member extends along a coil axis direction.   The endoscope according to claim 1, wherein the cover member entirely covers the coil.   The endoscope according to any one of claims 1 to 3, wherein the coil includes a rod-shaped core, and a coil is wound around the core.   The endoscope according to claim 4, wherein the cover member is formed of the same material as the core.   The endoscope according to any one of claims 1 to 5, wherein an insulating material is interposed between the cover member and the coil.   A processor, comprising: amplifying a current signal sent from a coil of an endoscope according to any one of claims 1 to 6 to calculate an endoscope position.   The processor according to claim 7, wherein a time division pulse signal for sequentially driving the plurality of magnetic field generation coils in time series is output to a magnetic field generation device including a plurality of magnetic field generation coils. An endoscope provided with at least one coil and a high-permeability cylindrical cover member that covers around the coil axis direction of the coil;
A magnetic field generator comprising a plurality of magnetic field generating coils;
A processor that outputs a time-division pulse signal that sequentially drives the plurality of magnetic field generating coils in time series, amplifies a magnetic detection signal sent from the endoscope, and calculates an endoscope position; An endoscope system characterized by that. At least one coil;
A medical device that can be inserted into the body, comprising: a cylindrical cover member having a high magnetic permeability that covers the coil in the axial direction.

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