JPH10230016A - Method for detecting medical instrument position, medical instrument set using therefor, medical instrument used therefor, medical instrument tip position detecting member and medical instrument tip position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a tip position in realtime at the time of insertion without executing X-ray photographing by providing the tip of a liniar medical instrument with a magnetic field generation source and detecting the generated magnetic field through the use of a magnetic sensor. SOLUTION: Before a catheter 5 is inserted, the reset switch of a magnetic detecting main body device is operated so as to detect magnetic field strength provided by peripheral environment. After the catheter 5 is continuously inserted to the inside of a patient, a stainless wire 10 is inserted to the hollow part of the catheter 5. The insertion is continued till the stopper 12 of the stainless wire 10 is restrained in the connecting part 6 of the catheter 5 and a permanent magnet 11 held by the stainless wire 10 is set in the tip position of the catheter 5 by the completion. After receiving the permanent magnet 11, the magnetic detecting main body device reads and displays magnetic field strength which is generated by the permanent magnet by subtracting the previously detected magnetic field strength of peripheral environment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the position of a medical device used in a form in which a part is inserted into a body,
The medical instrument set used therein, the medical instrument used for them, the medical instrument tip position detecting member and the medical instrument tip position detecting device, particularly, the tip of the medical instrument is set at a desired position without performing X-ray imaging. The present invention relates to a method for detecting the position of a medical instrument that can detect whether a medical instrument has been detected, a medical instrument set used for the method, a medical instrument, a medical instrument tip position detecting member, and a medical instrument tip position detecting device used for the set.

[0002]

2. Description of the Related Art In medical practice, medical instruments are inserted into the body of a patient for various purposes. One of them is central parenteral nutrition.

[0003] In this central venous nutrition method, a catheter is inserted from a vein near the clavicle of a patient, and the tip thereof is positioned in a central vein near the heart to inject a nutrient solution. Nutrient solution can be given.

[0004] A method of inserting a catheter used in the central parenteral nutrition will be described with reference to Figs. The instruments used at this time have been sterilized in advance, and the insertion operation is performed aseptically.

In order to insert a catheter into the body of a patient, an auxiliary device called a cannula 1 as shown in FIG. 17 is used. As shown in this figure, the cannula 1 is formed of a soft plastic tube, and has a handle 2 of a split plastic molded product at one end. When the handle 2 is opened outwardly, the cannula 1 can be divided into two parts according to the broken lines shown in the figure.

When inserting a catheter into a patient's body, as shown in FIG. 18, the metal puncture needle 4 of the syringe 3 is inserted into the cannula 1 from the handle 2 side, and in this state, as shown in FIG.
As shown in (1), the metal puncture needle 4 of the syringe 3 is pierced into the blood vessel of the patient together with the cannula 1.

Subsequently, the metal puncture needle 4 is extracted from the cannula 1, and instead, as shown in FIG. 20, a catheter 5 is inserted by a predetermined length so that the tip of the catheter 5 is inserted into a central vein near the heart. Position. Subsequently, FIG.
The cannula 1 is removed from the patient's body while dividing as shown in FIG.

When the distal end of the catheter 5 is inserted into the central vein position near the heart of the patient in this way, as shown in FIG. It is possible to supply the patient with a high concentration of nutrient solution.

However, when the catheter 5 is inserted, the distal end of the catheter 5 is not inserted into the central vein (B in the figure) near the heart as shown in FIG. May be inserted into a blood vessel in a direction different from the purpose, such as the jugular vein (C in the figure).

Therefore, conventionally, X-ray photography is performed after the insertion of the catheter 5 to confirm whether the tip of the catheter 5 has been inserted into the central vein near the heart, which is the correct insertion position.

Conventionally, when a linear medical device such as the catheter 5 is inserted into a patient without being limited to the central parenteral nutrition method, an X-ray image is taken after the medical device is inserted. It checks that the tip of the medical device has been inserted in the correct position.

[0012]

However, according to such a conventional technique, there is a problem that it is necessary to perform X-ray photography in order to check whether the tip of the catheter 5 has been inserted into a correct position. Was.

[0013] In a normal hospital, for convenience of management and cost,
The X-ray room and the hospital room where the catheter is inserted are separate rooms, and according to the related art, FIG.
In this state, the patient must be once taken out of the sickroom and transported to the X-ray room with the puncture part kept in a sterile state, which complicates the operation.

[0014] Using a portable x-ray,
Even if you take a radiograph in the sickroom,
The radiograph must be developed in the developing room, which is troublesome.

Further, when an inconvenient position of the distal end of the catheter 5 is confirmed by an X-ray photograph, the catheter 5
Must be pulled out and re-inserted into the correct position.However, once the catheter 5 is pulled out, the sterilized state of the punctured part may not be maintained, and the work may have to be started over from the beginning. is there.

In such a case, not only the patient's pain but also the economical problems arise because the used catheter 5 has to be discarded and a sterilized new catheter 5 must be used.

The problems of the prior art described above are not limited to the insertion of the catheter 5 by the central venous method, but a linear medical instrument such as the catheter 5 is inserted into the body of the patient, and the insertion position is determined. This is a problem that always occurs when confirming with an X-ray photograph.

The present invention has been made in view of the above circumstances, and performs an X-ray photograph to determine whether the tip of a medical instrument used in a form in which a part is inserted into a body is set at a desired position. Of a new method for detecting the position of a medical device that enables detection without any problem, provision of a new set of medical devices used for the method, and a new medical device, a member for detecting a position of a medical device tip, and a position of a medical device tip used therein It is intended to provide a detection device.

[0019]

In order to achieve this object, the present invention employs a configuration in which a magnetic field generating source is provided at the tip of a linear medical instrument used in a form in which a part is inserted into a body. .

Then, a configuration is adopted in which a magnetic field generated by a magnetic field generation source provided in the medical instrument is detected by using a magnetic sensor to provide a medical instrument tip position detecting device for detecting the tip position of the medical instrument. .

According to the present invention thus constructed, when a linear medical instrument such as a catheter having a magnetic field generating source at the distal end is inserted into a patient's body, the medical instrument distal end position detecting device performs the magnetic field generating operation. By detecting the magnetic field generated by the source, the tip position of the medical device is detected.

As a result, the position of the distal end of a linear medical device such as a catheter inserted into the body of a patient can be detected in real time at the time of insertion without performing X-ray photography. The problems they have can be solved at once.

Further, according to the present invention, a locking member which suppresses insertion beyond a specified amount and a magnetic field generating source at the tip are provided, and a part is inserted into a tubular medical device used in a form to be inserted into a body. Accordingly, a configuration is provided in which a linear medical instrument tip position detection member for setting a magnetic field generation source at the tip position of the medical instrument is prepared.

The magnetic field generated by the magnetic field generation source provided in the medical instrument tip position detecting member is detected by using a magnetic sensor, so that the medical instrument tip position detecting member is inserted into the medical instrument. A configuration is provided in which a medical instrument tip position detection device that detects the tip position is prepared.

According to the present invention having such a configuration, when a tubular medical device such as a catheter used in a form partially inserted into the body is inserted into the patient,
When a member for detecting the position of a medical instrument tip provided with a magnetic field generation source at the tip is inserted into the medical instrument, the magnetic field generation source is set at the tip of the medical instrument. By detecting the magnetic field generated, the tip position of the medical device is detected.

As a result, the position of the distal end of a tubular medical device such as a catheter inserted into the body of a patient can be detected in real time at the time of insertion without performing X-ray photography. The problems they have can be solved at once.

In the present invention, a configuration is adopted in which a magnetic sensor is provided at the tip of a linear medical instrument used in a form in which a part is inserted into the body. A medical instrument tip position detecting device for detecting a tip position of the medical instrument by detecting a magnetic field generated by a prescribed magnetic field generation source provided outside the body using a detection value of a magnetic sensor means provided in the medical instrument. Is adopted.

According to the present invention thus constructed, when a linear medical instrument such as a catheter having a magnetic sensor means at the distal end is inserted into the patient's body, the medical instrument distal end position detecting device operates with the magnetic sensor. The position of the distal end of the medical device is detected by detecting the magnetic field generated by a prescribed magnetic field source provided outside the body using the detection value of the means.

As a result, the position of the distal end of a linear medical instrument such as a catheter inserted into the body of a patient can be detected in real time at the time of insertion without performing X-ray photography. The problems they have can be solved at once.

Further, according to the present invention, a locking member for suppressing insertion beyond a specified amount and a magnetic sensor means at the tip are provided, and a part thereof is inserted into a tubular medical instrument used in a form inserted into a body. Accordingly, a configuration is provided in which a linear medical instrument tip position detecting member for setting the magnetic sensor means at the tip position of the medical instrument is prepared.

Then, by detecting the magnetic field generated by a prescribed magnetic field source provided outside the body using the detection value of the magnetic sensor means provided in the medical instrument tip position detecting member,
A configuration is provided in which a medical instrument tip position detecting device for detecting the tip position of the medical instrument is prepared.

According to the present invention having such a configuration, when a tubular medical device such as a catheter used in a form partially inserted into the body is inserted into the patient,
When a member for detecting the position of a medical instrument tip provided with a magnetic sensor means at the tip is inserted into the medical instrument, the magnetic sensor means is set at the tip of the medical instrument. Using the detection value of
By detecting a magnetic field generated by a prescribed magnetic field source provided outside the body, the tip position of the medical device is detected.

As a result, the position of the distal end of a tubular medical instrument such as a catheter inserted into the body of a patient can be detected in real time at the time of insertion without performing X-ray photography. The problems they have can be solved at once.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail according to embodiments. FIG. 1 shows an embodiment of the present invention. Here, in the figure, the same components as those shown in FIGS. 17 to 22 are denoted by the same symbols.

As shown in this figure, in the present invention according to this embodiment, after inserting the catheter 5 into the patient's body, a flexible stainless wire 10 is inserted into the hollow portion of the catheter 5. take.

The stainless wire 10 has substantially the same length as the catheter 5, has a permanent magnet 11 at the distal end of the insertion destination, and is engaged with the connecting portion 6 of the catheter 5 at the insertion end. And a knob 13 protruding from the stopper 12.
And

According to this configuration, the stainless steel wire 10
Is inserted into the catheter 5 to the position of the stopper 12, the permanent magnet 11 is set at the distal end position of the catheter 5.

Then, a configuration is adopted in which a magnetic sensor 20 for detecting a magnetic field generated by the permanent magnet 11 of the stainless wire 10 is provided in contact with the body surface of the patient. This magnetic sensor 20 is fixed to a bed on which a patient sleeps, as shown in FIG.
As shown in (b), it is placed and placed directly on the patient's body. Here, reference numeral 30 shown in the figure denotes a magnetic detection main unit that executes signal processing of a detection value of the magnetic sensor 20.

The arrangement position of the magnetic sensor 20 is determined by the insertion position of the catheter 5. For example, in the case of the central vein method, the magnetic sensor 20 is disposed at a position indicated by the central vein near the patient's heart.

The stainless wire 10 may be a single wire or a stranded wire as long as it has flexibility, but its material does not affect the magnetic field generated by the permanent magnet 11 provided at the tip. Non-magnetic (paramagnetic) type is desirable. In addition, the thickness is adjusted to the size of the catheter 5. For example, when the size of the catheter 5 is 14 gauge, the wire diameter is about 0.97 mm, when it is 16 gauge, it is about 0.89 mm, and when it is 18 gauge, it is about 0.64 mm.

The permanent magnet 11 provided at the tip of the stainless steel wire 10 may be of any type as long as it does not break during use. In view of the above, a metallic permanent magnet is desirable.

The permanent magnet 11 is magnetized after being welded to the stainless steel wire 10 in consideration of the possibility of losing magnetism due to a high temperature above the Curie point due to welding heat. , Attached to the tip of the stainless steel wire 10. When the magnetization is performed first, it may be attached by bonding. Further, in order to strengthen the connection between the permanent magnet 11 and the stainless steel wire 10, a process such as covering a rubber tube or a heat shrink tube on the connection portion or applying a coating to the connection portion is performed. Is preferred.

The magnetization direction at this time may be an axial direction as shown in FIG. 3A or a radial direction as shown in FIG. 3B. According to the former magnetization direction, the distance between the magnetic poles can be increased, so that there is a characteristic that the permeance coefficient is increased and the magnetic field formed by the magnet is increased. Further, by swinging the stainless steel wire 10 in the axial direction (α direction shown in FIG. 3A), there is a feature that the magnetic field intensity to be detected by the magnetic sensor 20 can be changed.

On the other hand, according to the latter magnetization direction, the strength of the magnetic field to be detected by the magnetic sensor 20 can be changed by rotating the stainless wire 10 in the circumferential direction (β direction shown in FIG. 3B). There are features. In particular, in the latter magnetization direction, with the rotation of the stainless steel wire 10,
Since the N pole and the S pole of the magnet appear alternately with respect to the magnetic sensor 20, the intensity of the magnetic field to be detected by the magnetic sensor 20 can be greatly changed.

The edge of the permanent magnet 11 is chamfered so as not to damage the inner wall of the catheter 5. The stainless wire 10 having the permanent magnet 11 / stopper 12 / knob 13 has been sterilized in advance and may be used disposably.

The magnetic sensor 20 is a stainless steel wire 10
It is provided to detect the magnetic field generated by the permanent magnet 11 of the magnetic head. Examples of the magnetic sensor 20 include a flux gate type magnetic sensor generally used widely and a magnetoresistive effect element (for example, Honeywell INC., USA).
HMC1001) manufactured by the company or a Hall element can be used. Further, as described later, when employing a configuration in which an AC magnetic field is generated using the coil 50 instead of the permanent magnet 11, a search coil that detects the AC magnetic field by induced electromotive force can be used.

FIG. 4 shows an example of the device configuration of the magnetic detection main unit 30 (shown in FIG. 2). As shown in the figure, the magnetic detection main unit 30 includes an amplifier for amplifying the output voltage of the magnetic sensor 20, an A / D converter for converting the output voltage of the amplifier into a digital signal, and an A / D converter. A CPU for processing digital signals to be output, a plurality of LEDs for externally displaying the strength of the detected magnetic field,
A reset switch is provided for instructing the PU to detect a magnetic field of the surrounding environment.

According to this configuration, the magnetic detection main unit 30
As shown in FIG. 5A, when the reset switch is operated by a doctor who inserts the catheter 5 and a detection instruction of the magnetic field strength of the surrounding environment is issued, the output voltage of the magnetic sensor 20 is reduced. By reading, the magnetic field strength (y) of the surrounding environment is detected.
In the process of detecting the magnetic field intensity generated by the permanent magnet 11 included in the above, for example, by periodically reading the output voltage of the magnetic sensor 20, the magnetic field intensity (x) at that time is detected, and the detected magnetic field intensity (x) is detected. By subtracting the magnetic field strength (y) of the surrounding environment detected earlier from the magnetic field strength (x),
The magnetic field intensity (z) generated by the permanent magnet 11 of the stainless wire 10 is detected.

Then, the detected stainless wire 1
According to the magnitude of the magnetic field strength (z) generated by the permanent magnet 11 having 0, as shown in FIG. 5B, by turning on one of the LEDs, the doctor who inserts the catheter 5 Processing for displaying the magnitude of the magnetic field strength (z) is performed.

Next, the embodiment shown in FIG. 1 will be described. The doctor who inserts the catheter 5 first turns on the reset switch of the magnetic detection main unit 30 before inserting the catheter 5,
Issues an instruction to detect the magnetic field strength of the surrounding environment.

Upon receiving this instruction, the magnetic detection main unit 30 detects the magnetic field strength (such as geomagnetism) of the surrounding environment by reading the magnetic field strength detected by the magnetic sensor 20.

Subsequently, the doctor inserts the catheter 5 into the patient's body and then inserts the stainless steel wire 10 into the hollow portion of the catheter 5 according to the procedure described with reference to FIGS. 17 to 22 described above. In this insertion, the stopper 12 of the stainless wire 10 is
When the operation is completed, the permanent magnet 11 of the stainless steel wire 10 is set at the distal end position of the catheter 5.

Receiving this permanent magnet 11, the magnetic detection main unit 30 calculates the intensity of the magnetic field detected by the magnetic sensor 20 from
By subtracting the magnetic field strength of the surrounding environment detected earlier, the magnetic field strength generated by the permanent magnet 11 is read, and the corresponding LED is turned on.

When the catheter 5 is inserted into a proper body position, the magnetic sensor 20 detects the magnetic field generated by the permanent magnet 11, and the LED that is turned on at this time indicates a strong magnetic field strength. Can confirm that the catheter 5 has been inserted into a regular body position.

On the other hand, when the catheter 5 is not inserted at a proper position, the magnetic sensor 20 cannot detect the magnetic field generated by the permanent magnet 11, so that the LED turned on at this time shows a weak magnetic field strength. The physician can confirm that the catheter 5 has not been inserted into the proper body position.

At this time, when the magnetization direction of the permanent magnet 11 is the axial direction as shown in FIG. 3A, the doctor swings the stainless wire 10 in the axial direction (α direction in the figure). By checking whether or not the lit LED changes, it is determined whether or not the magnetic sensor 20 is detecting the magnetic field intensity generated by the permanent magnet 11.

The direction of magnetization of the permanent magnet 11 is shown in FIG.
In the case of the radial direction as shown in (b), by rotating the stainless steel wire 10 in the circumferential direction (β direction in the figure), it is checked whether or not the lit LED changes. Then, it is determined whether or not the magnetic sensor 20 detects the magnetic field intensity generated by the permanent magnet 11.

That is, since the magnetic field strength of the surrounding environment does not change even if the stainless wire 10 rotates or swings, the detection value of the magnetic sensor 20 fluctuates due to the rotation or swing of the stainless wire 10. This means that the magnetic sensor 20 is detecting the magnetic field generated by the permanent magnet 11. From this, the doctor can confirm whether or not the magnetic sensor 20 is actually detecting the magnetic field intensity generated by the permanent magnet 11 by rotating or swinging the stainless wire 10.

In the description of this embodiment, the stainless steel wire 10 is inserted into the hollow portion of the catheter 5 after the catheter 5 is inserted into the patient's body, but the stainless wire 10 is inserted into the catheter 5 in advance. Then, it may be inserted into the body of the patient together.

Further, in the description of this embodiment, as described with reference to FIG. 2, the configuration is adopted in which the magnetic sensor 20 is disposed at a fixed position in advance. It is possible to detect where in the body the catheter 5 is inserted and where in the patient's body the catheter 5 is being inserted.

Generally, the magnetic sensor 20 has a sensitivity axis, and exhibits a characteristic that the detection sensitivity varies depending on the direction of the magnetic field. From this, for example, two magnetic sensors 20 are prepared, and the two magnetic sensors 20 are disposed, for example, in such a manner that the directions of maximum detection sensitivity are orthogonal to each other. The configuration in which processing is performed using the larger of the two
By rotating 0, for example, processing is performed using the maximum magnetic field strength detected at that time. In the case of following the former configuration, a plurality of magnetic sensors 2
The use of one in which 0 is mounted on one chip simplifies mounting.

In the embodiment shown in FIG. 1, a configuration is adopted in which the permanent magnet 11 is disposed at the distal end of the catheter 5 by using the stainless steel wire 10 having the permanent magnet 11 at the distal end. The present invention can also be realized by adopting a configuration in which the permanent magnet 11 is directly provided at the distal end portion of the catheter 5.

That is, as shown in FIG. 6A, a permanent magnet 11 is embedded in a thick portion at the tip of a catheter 5 called a single lumen having one internal cavity,
As shown in FIG. 6B, the permanent magnet 11 is embedded in a thick portion at the tip of the catheter 5 called a double lumen having two internal cavities as in the case of FIG. It is possible to confirm that the catheter 5 has been inserted into a proper body position.

FIG. 7 shows another embodiment of the device configuration of the magnetic detection main unit 30. The magnetic detection main unit 30 of this embodiment is used when using the triaxial magnetic sensor 20a. In addition, this magnetic detection main unit 30
Is applicable to both the case where the stainless steel wire 10 having the permanent magnet 11 at the tip is used and the case where the catheter 5 having the permanent magnet 11 at the tip is used.

As shown in FIG. 8, the triaxial magnetic sensor 20a includes a magnetic sensor 20x having a sensitivity on the X axis, a magnetic sensor 20y having a sensitivity on the Y axis, and a magnetic sensor 20z having a sensitivity on the Z axis. Is provided, a function of accurately detecting the magnitude of the magnetic field regardless of the direction of the magnetic field.

The magnetic detection main unit 30 shown in FIG. 7 uses the three-axis type magnetic sensor 20a.
An amplifier 40x for amplifying the output voltage of 0x, an amplifier 40y for amplifying the output voltage of the magnetic sensor 20y, an amplifier 40z for amplifying the output voltage of the magnetic sensor 20z, and removing unnecessary noise from the output signal of the amplifier 40x. A low-pass filter 41x, a low-pass filter 41y for removing unnecessary noise components from the output signal of the amplifier 40y, a low-pass filter 41z for removing unnecessary noise components from the output signal of the amplifier 40z, and low-pass filters 41x, y,
A multiplexer 42 for selecting an output signal of the signal z, and an A for converting the output voltage of the multiplexer 42 into a digital signal.
An A / D converter 43, a CPU 44 for calculating a magnitude of a magnetic field detected by the three-axis magnetic sensor 20a by executing a program (not shown) with a digital signal output from the A / D converter 43 as an input, and a CPU 44 A plurality of LEDs 45 for externally displaying the magnitude of the magnetic field detected by
A configuration including a reset switch 46 for instructing the detection of the magnetic field of the surrounding environment with respect to 44 is adopted.

Here, the low-pass filters 41x, y, z
Is provided in order to remove the influence of the disturbance AC magnetic field having a large component in the commercial power supply frequency and to detect only the DC magnetic field generated by the permanent magnet 11. In consideration of rotating or rocking the catheter 5 in which the catheter 11 is provided, for example, the catheter 5 has a filtering characteristic of passing up to 10 Hz.

FIG. 9 shows an embodiment of a processing flow of the magnetic detection main unit 30 executed when adopting the configuration of this embodiment. That is, when using the three-axis magnetic sensor 20a, the magnetic detection main unit 30 first performs necessary initialization processing in step 1 as shown in the processing flow of FIG. The process proceeds to a monitoring process for determining whether or not the reset switch 46 has been operated according to a prescribed cycle.

In this step 2, the reset switch 46
Is detected, the magnetic field of the surrounding environment
In the detection process, in step 3, the multiplexer 42
To read the output voltage of the magnetic sensor 20x.
And convert it to a digital signal to obtain the variable x₀Stored in
In step 4, controlling the multiplexer 42
To read the output voltage of the magnetic sensor 20y and
And convert it to a variable y ₀And the following step 5
By controlling the multiplexer 42, the magnetic sensor
Read the output voltage of 20z and convert it to digital signal
Variable z₀To be stored.

On the other hand, in step 2, the reset switch 4
6 detects that the permanent magnet 1 is not operated.
In step 6 of the process for detecting the magnetic field generated by step 1,
By controlling the multiplexer 42, the magnetic sensor 20
is converted into a digital signal and stored in the variable x ₁ reads the output voltage of the x, In step 7, the multiplexer 4
By controlling the 2, and converted into a digital signal and stored in the variable y ₁ reads the output voltage of the magnetic sensor 20y,
In step 8, by controlling the multiplexer 42 and stored in the variable z ₁ is converted into a digital signal by reading the output voltage of the magnetic sensor 20z.

Subsequently, in step 9, for example, d = [(x ₁ −x ₀ ) ² + (y ₁ −y ₀ ) ² + (z ₁ −
The magnetic field intensity d generated by the permanent magnet 11 is calculated according to the formula of z ₀ ) ² ] ^1/2 without being affected by the magnetic field generated by the surrounding environment. Then, in the subsequent step 10, the LED 45 is turned on according to the calculated magnetic field strength d.

As a result, the doctor can check whether the catheter 5 has been inserted into a proper body position. At this time, as described above, the doctor confirms that the magnetic field generated by the permanent magnet 11 is generated by rotating or swinging the stainless steel wire 10 or the catheter 5 having the permanent magnet 11 disposed at the distal end. However, a configuration may be adopted in which the amount of change in the magnetic field strength at this time is detected, and the LED 45 is turned on in accordance with the detected amount of change in the magnetic field strength.

When this configuration is adopted, a band-pass filter having a pass band of, for example, 0.1 to 10 Hz is prepared in place of the low-pass filters 41x, y, and z to cut the DC component of the detected magnetic field strength. At the same time, a configuration is adopted in which the amount of change in the magnetic field intensity that fluctuates with the operation of the doctor is detected.

Here, since the band-pass filter can be realized by a combination of a low-pass filter and a high-pass filter, a configuration using the low-pass filters 41x, y, and z as they are, and combining with the high-pass filter by digital signal processing of the CPU 44 is adopted. Thus, a configuration for realizing a band-pass filter may be adopted. In this case, the circuit configuration of the embodiment in FIG. 7 is used as it is. Note that a high-pass filter using digital signal processing may use a technique widely used in digital signal processing, such as an infinite-length impulse response (IIR) filter or a finite-length impulse response (FIR) filter.

A particular problem when using the permanent magnet 11 is geomagnetism. In order to remove the influence of the terrestrial magnetism, a configuration is adopted in which the operation of the reset switch 46 is used as a trigger to detect a magnetic field generated by the surrounding environment, and the configuration is adopted in which the magnetic field is subtracted from the detected magnetic field. As shown in FIG. 10, two triaxial magnetic sensors 20a are prepared to further enhance the removal accuracy of the patient, and the sensitivity axes (X / Y / Z axes in FIG. 8) are adjusted and the body surface of the patient is adjusted. For example, it is effective to adopt a configuration provided with a distance of about 20 cm.

Permanent magnet 11 inserted inside patient's body
Is located at a short distance from the three-axis magnetic sensor 20a, so that the magnetic field generated by the permanent magnet 11 shows different strengths in different directions on the two three-axis magnetic sensors 20a. . On the other hand, since the geomagnetism is generated at infinity, the two triaxial magnetic sensors 20a exhibit the same strength in almost the same direction. From this, by calculating the difference value between the detection values of the two three-axis magnetic sensors 20a, the influence of the terrestrial magnetism can be removed with higher accuracy.

In the case of employing this configuration, as shown in FIG. 11, the magnetic detection main unit 30 associates the amplifiers 40x, y, and 40 with the three triaxial magnetic sensors 20a, respectively.
A configuration including z and low-pass filters 41x, y, z is adopted.

FIG. 12 shows an embodiment of a processing flow of the magnetic detection main unit 30 executed when adopting the configuration of this embodiment. That is, the magnetic detection main unit 30 includes the first triaxial magnetic sensor 20a and the second triaxial magnetic sensor 20a.
When adopting a configuration in which a is arranged adjacently while adjusting the sensitivity axis, as shown in the processing flow of FIG. 12, first, if necessary initialization processing is performed in step 1, the process proceeds to step 2. Then, according to a prescribed cycle, a monitoring process starts as to whether or not the reset switch 46 has been operated.

In step 2, the reset switch 46
Is detected, the process starts to detect the magnetic field of the surrounding environment.
By controlling the is converted into a digital signal by reading the output voltage of the magnetic sensor 20x of the first three-axis magnetic sensor 20a and stored in the variable x _10, in the subsequent step 4, by controlling the multiplexer 42 is converted into a digital signal by reading the output voltage of the magnetic sensor 20y of the first three-axis magnetic sensor 20a and stored in the variable y _10, in the subsequent step 5, by controlling the multiplexer 42, the first
Into a variable z ₁₀ is converted into a digital signal by reading the output voltage of the magnetic sensor 20z triaxial magnetic sensor 20a for. Subsequently, in step 6, by controlling the multiplexer 42, and stored in the variable x ₂₀ converts the digital signal reads the output voltage of the magnetic sensor 20x of the second three-axis magnetic sensor 20a, the following step 7 in, by controlling the multiplexer 42, and converted into a digital signal by reading the output voltage of the magnetic sensor 20y of the second three-axis magnetic sensor 20a and stored in the variable y _20, in step 8, the multiplexer 42 by controlling, and stores the converted into a digital signal by reading the output voltage of the magnetic sensor 20z of the second three-axis magnetic sensor 20a to the variable z _20.

On the other hand, in step 2, the reset switch 4
6 detects that the permanent magnet 1 is not operated.
In step 9 of detecting the magnetic field generated by step 1,
By controlling the multiplexer 42, and stored in the variable x ₁₁ is converted into a digital signal by reading an output voltage of the magnetic sensor 20x of the first three-axis magnetic sensor 20a, at subsequent step 10, controls the multiplexer 42 Thus, the magnetic sensor 20y of the first three-axis magnetic sensor 20a
Stored in the variable y ₁₁ is converted into a digital signal by reading the output voltage, in the subsequent step 11, the multiplexer 4
By controlling the 2, into a variable z ₁₁ is converted into a digital signal by reading the output voltage of the magnetic sensor 20z of the first three-axis magnetic sensor 20a.

Subsequently, in step 12, by controlling the multiplexer 42, the second three-axis type magnetic sensor 20a is controlled.
Is converted into a digital signal and stored in the variable x ₂₁ reads the output voltage of the magnetic sensor 20x, the subsequent step 13
In, by controlling the multiplexer 42, and stored in the variable y ₂₁ is converted into a digital signal by reading the output voltage of the magnetic sensor 20y of the second three-axis magnetic sensor 20a,
In the following step 14, by controlling the multiplexer 42, the magnetic sensor 20 of the second triaxial magnetic sensor 20a is controlled.
into a variable z ₂₁ and converted into a digital signal by reading an output voltage of z.

[0082] Then, in step 15, for _{example, d = [((x 11} -x 21) - (x 10 -x 20)) 2 + ((y 11 -y
_{21) - (y 10 -y 20} )) 2 + ((z 11 -z 21) - (z 10 -z
₂₀₎₎ ^2] and calculated as ^1/2 _{formula, d = | (x 11 -x} 21) - (x 10 -x 20) | + | (y 11 -
_{y 21) - (y 10 -y} 20) | + | (z 11 -z 21) - (z 10
-Z ₂₀₎ | and calculation formula _{of, d = | [(x 11} 2 + y 11 2 + z 11 2) 1/2 - (x 21 2 + y 21
² + z ₂₁ ² ) ^1/2 ]-[(x ₁₀ ² + y ₁₀ ² + z ₁₀ ² ) ^{1/ 2-} (
x ₂₀ ² + y ₂₀ ² + z ₂₀ ² ) ^1/2 ] | According to the calculation formula, the magnetic field strength d corresponding to the magnetic field strength generated by the permanent magnet 11 (the (Corresponding to a difference value between the magnetic field strength of the permanent magnet 11 detected by the first triaxial magnetic sensor 20a and the magnetic field strength of the permanent magnet 11 detected by the second triaxial magnetic sensor 20a). . Then, in the subsequent step 15, the LED is determined according to the calculated magnetic field strength d.
45 is turned on.

Thus, the doctor can check whether or not the catheter 5 has been inserted into a proper body position. Here, the two triaxial magnetic sensors 20a detect almost the same geomagnetism as described above. That is,
If the two triaxial magnetic sensors 20a have the same sensitivity,
Since “x ₁₀ = x ₂₀ , y ₁₀ = y ₂₀ , z ₁₀ = z ₂₀ ”,
Steps 3 to 8 can be omitted.

When employing this configuration, as described above, the doctor rotates or swings the stainless steel wire 10 or the catheter 5 having the permanent magnet 11 disposed at the distal end, thereby generating the permanent magnet 11. However, by preparing a band-pass filter instead of the low-pass filters 41x, y, and z, only the amount of change in the magnetic field strength at this time is detected, and the detection is performed. A configuration may be adopted in which the LED 45 is turned on in accordance with the fluctuation amount of the magnetic field strength.

In the embodiment of FIG. 10, a method using two triaxial magnetic sensors 20a is employed, but a method using two magnetic sensors 20 having only one sensitivity axis may be employed.

In order to completely remove the influence of geomagnetism, a configuration in which an AC magnetic field generating source is provided at the tip of the stainless steel wire 10 or the catheter 5 will be adopted. For example, as shown in FIG. 13, a coil 50 composed of an enamel wire or the like is embedded at the tip of the catheter 5, and a current of, for example, 280 Hz is passed through the coil 50 to generate an AC magnetic field. Become. Hereinafter, for convenience of description, it is assumed that the coil 50 is provided on the catheter 5.

The reason why a current of 280 Hz is applied to the coil 50 is to avoid the influence of an AC magnetic field generated from the commercial power supply frequency, which is 50 Hz or 60 Hz in Japan.

FIG. 14 shows an embodiment of the configuration of the magnetic detection main unit 30 in the case of employing this configuration. In the figure,
The same components as those described in FIG. 7 are indicated by the same symbols.

The magnetic detection main unit 30 of this embodiment includes an AC power supply 60 for passing an 280 Hz AC current through the coil 50 of the catheter 5, and a synchronization signal for generating a square wave in phase with the AC signal output from the AC power supply 60. A generation circuit 61, a band pass filter 62x for extracting a 280 Hz component of the output signal of the amplifier 40x, and a band pass filter 6 for extracting a 280 Hz component of the output signal of the amplifier 40y
2y, a band-pass filter 62z for extracting a 280-Hz component of the output signal of the amplifier 40z, a PSD 63x for multiplying the output signal of the band-pass filter 62x by the synchronization signal generated by the synchronization signal generation circuit 61, and a band-pass filter 62y. A PSD 63y that multiplies the output signal of the synchronous signal generation circuit 61 by the synchronization signal generated by the synchronization signal generation circuit 61, a PSD 63z that multiplies the output signal of the band-pass filter 62z by the synchronization signal generated by the synchronization signal generation circuit 61,
A low-pass filter 64x for blocking unnecessary AC components output by 63x, a low-pass filter 64y for blocking unnecessary AC components output by the PSD 63y, and a PSD 63z
And a low-pass filter 64z that cuts off unnecessary AC components output from the control circuit.

Here, the band-pass filters 62x, y,
The passband of z is the catheter 5
Is set to, for example, 280 ± 10 Hz in consideration of rotating or rocking the.

The low-pass filters 64x, y, z
Is a PSD (Phase Sensitive Detector) 63x, y,
By multiplying the input signal and the synchronization signal by z, a signal having a frequency equal to the sum of the two signals and a signal having a frequency equal to the difference between the two signals are output. Provided for extracting a signal having a frequency of Therefore, the output signals of the low-pass filters 64x, y, and z indicate a DC voltage (having an AC component that is linked to the movement of the catheter 5) according to the magnitude of the AC magnetic field detected by the triaxial magnetic sensor 20a. Will be.

FIG. 15 shows an embodiment of a processing flow of the magnetic detection main unit 30 executed when adopting the configuration of this embodiment. That is, as shown in the processing flow of FIG. 15, the magnetic detection main unit 30 first performs necessary initialization processing in step 1, and then determines in step 2 whether a specified detection cycle has been reached. Judge.

When it is determined in step 2 that the detection cycle has been reached, in step 3 that follows, the multiplexer 42 is controlled to control the magnetic sensor 20 of the three-axis magnetic sensor 20a.
The output voltage of x is read, converted into a digital signal and stored in a variable x.
Is read, the output voltage of the magnetic sensor 20y of the three-axis type magnetic sensor 20a is read, converted into a digital signal and stored in the variable y, and in the subsequent step 5, the multiplexer 42 is controlled to The output voltage of the magnetic sensor 20z of the magnetic sensor 20a is read, converted into a digital signal, and stored in a variable z.

Subsequently, in step 6, for example, according to a calculation formula of d = [(x) ² + (y) ² + (z) ² ] ^1/2 , the magnitude of the output signal of the low-pass filter 64x, y, z By calculating the magnetic field strength, the magnetic field strength d at the position where the triaxial magnetic sensor 20a provided by the coil 50 is arranged is calculated. This magnetic field strength d has an AC component that is linked to the movement of the catheter 5.

Then, in the following step 7, the LED 45 is turned on in accordance with the calculated fluctuating magnetic field strength d, and the process returns to step 2 to start the detection processing in the next detection cycle.

Thus, the doctor can confirm whether or not the catheter 5 has been inserted into a proper body position. In the embodiment of FIG. 14, the three-axis magnetic sensor 20
Although the method using a is adopted, a method using the magnetic sensor 20 having only one sensitivity axis may be adopted.

In the embodiment described above, the permanent magnet 11 and the coil 50 serving as a magnetic field generating source are arranged at the tip of the stainless steel wire 10 and the catheter 5, and are provided outside the body.
Although the configuration in which the magnetic sensor 20 is provided is adopted, the stainless steel wire 10, a linear member or
A configuration may be adopted in which the magnetic sensor 20 is provided at the tip of the body, and the permanent magnet 11 and the coil 50 serving as a magnetic field generation source are provided outside the body.

For example, as shown in FIG. 16, a linear member constituted by disposing a triaxial magnetic sensor 20a at the tip and coating the lead wire of the triaxial magnetic sensor 20a with resin or the like. 70 is prepared and inserted into the catheter 5, and the permanent magnet 1 is placed outside the body.
A configuration including a magnetic field generation source 71 composed of a coil 1 and a coil 50 may be employed.

Since the fine magnetic sensor 20 has been provided on the market, this configuration can be adopted. For example, HMC10 manufactured by Honeywell INC.
The sensor chip portion of 01 is still 0.76 mm x 0.7
It is about 6 mm, which is sufficiently applicable.

In the case of adopting this configuration, since the positional relationship between the magnetic sensor 20 and the magnetic field generating source 71 is only reversed with respect to the above-described embodiment, the magnetic detection main unit 30 of the above-described embodiment is directly used. It will be applicable.

In the embodiment of FIG. 16, the method using the three-axis magnetic sensor 20a is employed, but the method using the magnetic sensor 20 having only one sensitivity axis may be employed.
Although the present invention has been described with reference to the illustrated embodiments, the present invention is not limited thereto. For example, in the embodiment, the stainless wire 10 is used as the one to be inserted into the catheter 5, but the wire is not limited to the stainless wire 10 as long as it is a linear body.

In the embodiment, the detected magnetic field strength is displayed by using the LED. However, the detected magnetic field strength may be displayed by using a meter or by using a sound.

[0103]

As described above, according to the present invention,
The distal end position of a linear medical instrument such as a catheter inserted into the body of a patient can be detected without performing X-ray photography. Then, the tip position of the medical instrument can be detected in real time at the time of insertion.

From this, it becomes possible to detect the tip position of the catheter used for central parenteral nutrition in real time without performing X-ray imaging, and to perform X-ray imaging of the tip position of the catheter for angiography. In addition, it is possible to detect the position of the drainage tube inserted into the body in real time without performing X-ray photography.

Then, the position of the tip of the sensor for measuring the pressure, temperature and the like inserted into the body can be detected in real time without performing X-ray photography.

[Brief description of the drawings]

FIG. 1 is an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an arrangement method of a magnetic sensor.

FIG. 3 is an explanatory diagram of a permanent magnet.

FIG. 4 is a configuration diagram of a magnetic detection main unit.

FIG. 5 is an explanatory diagram of a process performed by the magnetic detection main unit.

FIG. 6 is another embodiment of the present invention.

FIG. 7 is a configuration diagram of a magnetic detection main unit.

FIG. 8 is an explanatory diagram of a triaxial magnetic sensor.

FIG. 9 is a processing flow executed by the magnetic detection main unit.

FIG. 10 is an explanatory diagram of an arrangement of a magnetic sensor.

FIG. 11 is a configuration diagram of a magnetic detection main unit.

FIG. 12 is a processing flow executed by the magnetic detection main unit.

FIG. 13 is an explanatory diagram of an AC magnetic field generation source.

FIG. 14 is a device configuration diagram of a magnetic detection main unit.

FIG. 15 is a processing flow executed by the magnetic detection main unit.

FIG. 16 is another embodiment of the present invention.

FIG. 17 is an explanatory diagram of a cannula.

FIG. 18 is an explanatory view of insertion of a catheter.

FIG. 19 is an explanatory view of insertion of a catheter.

FIG. 20 is an explanatory view of insertion of a catheter.

FIG. 21 is an explanatory view of insertion of a catheter.

FIG. 22 is an explanatory view of insertion of a catheter.

FIG. 23 is an explanatory view of insertion of a catheter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cannula 2 Handle 3 Syringe 4 Metal puncture 5 Catheter 6 Connection part 10 Stainless wire 11 Permanent magnet 12 Stopper 13 Knob 20 Magnetic sensor 30 Magnetic detection main unit

Claims (20)

[Claims] 1. A first step of detecting a magnetic field generated by a linear medical device having a magnetic field generation source at a tip, which is used in a form in which a part is inserted into a body, and detecting in the first step. A step of detecting the position of the distal end of the medical device by displaying the magnitude of the magnetic field thus obtained. 2. A linear medical device having a magnetic field generation source at a distal end, which is used in a form in which a part is inserted into a body, and detecting a magnetic field generated by the magnetic field generation source included in the medical device, A medical instrument set, comprising: a medical instrument tip position detecting device that detects a tip position of the medical instrument. 3. A medical device comprising: a linear medical member used in a form in which a part thereof is inserted into a body; and a magnetic field generating source disposed at a distal end of the medical member to generate a magnetic field. And medical instruments. 4. A medical instrument tip position detecting device used in a form in which a part is inserted into a body and used for detecting a tip position of a linear medical instrument having a magnetic field generation source at the tip, comprising: Magnetic sensor means for detecting a magnetic field generated by a magnetic field generation source provided in the medical instrument from a detection value of the magnetic sensor means, thereby detecting a tip position of the medical instrument. And a medical instrument tip position detecting device. 5. A medical device comprising: a locking member for preventing insertion beyond a specified amount; and a magnetic field generation source at a tip, and a part inserted into a tubular medical device used in a form inserted into a body. A first step of detecting a magnetic field generated by a linear medical instrument tip position detecting member for setting the magnetic field generation source at the tip position of the medical instrument, and a magnitude of the magnetic field detected in the first step. A second step of detecting the distal end position of the medical device by displaying the medical device. 6. A medical device having a locking member for preventing insertion beyond a specified amount and a magnetic field generation source at a tip, and being partially inserted into a tubular medical device used in a form to be inserted into a body. By detecting a magnetic field generated by a magnetic field generation source provided in the medical device tip position detection member, which is a linear medical device tip position detection member that sets the magnetic field generation source at the tip position of the medical device, A medical instrument set comprising: a medical instrument tip position detection device that detects a tip position of a medical instrument. 7. A linear medical device insertion member used by being inserted into a tubular medical device used in a form in which a part thereof is inserted into a body, and a medical device insertion member provided at a distal end of the medical device insertion member. A magnetic field generating source for generating a magnetic field; and a magnetic field generating source disposed at the medical device insertion member for preventing insertion of the medical device insertion member beyond a specified amount, thereby setting the magnetic field generating source at a distal end position of the medical device. A member for detecting a distal end position of a medical device, comprising: a locking means. 8. A medical device tip position detecting device used for detecting a distal position of a tubular medical device used in a form in which a part thereof is inserted into a body, wherein magnetic sensor means for detecting a magnetic field; From the detection value of the magnetic sensor means, a locking member that suppresses insertion beyond a specified value and a magnetic field generation source at the tip are provided, and when inserted into the medical instrument, the magnetic field generation is generated at the tip position of the medical instrument. A medical instrument tip position detecting means for detecting a tip position of the medical instrument by detecting a magnetic field generated by a linear medical instrument tip position detecting member for setting a source. Tip position detector. 9. A specified magnetic field source provided outside the body is generated from a magnetic field detection value output by a linear medical instrument having a magnetic sensor means at a tip, which is used in a form in which a part is inserted into a body. A first step of detecting a magnetic field, and a second step of detecting the position of the distal end of the medical device by displaying the magnitude of the magnetic field detected in the first step. A method for detecting the position of a medical device. 10. A rule that is used in a form in which a part is inserted into a body and is provided outside the body based on a linear medical instrument provided with a magnetic sensor means at a tip thereof and a detection value of the magnetic sensor means provided in the medical instrument. A medical instrument set, comprising: a medical instrument tip position detecting device that detects a tip position of the medical instrument by detecting a magnetic field generated by the magnetic field generation source. 11. A medical device comprising: a linear medical member used in a form in which a part thereof is inserted into a body; and magnetic sensor means disposed at a distal end of the medical member and detecting a magnetic field. And medical instruments. 12. A medical device tip position detecting device used for detecting a position of a distal end of a linear medical device having a magnetic sensor means at a distal end, which is used in a form in which a part is inserted into a body, comprising: A magnetic field generating source that generates a magnetic field, an input unit that inputs a detection value of a magnetic sensor unit included in the medical instrument, and a detection value input by the input unit, by detecting a magnetic field generated by the magnetic field source, A medical instrument tip position detecting device for detecting a tip position of the medical instrument. 13. A medical device provided with a locking member for preventing insertion beyond a specified amount and a magnetic sensor means at a tip, and being partially inserted into a tubular medical device used in a form to be inserted into a body. A first magnetic field generated by a prescribed magnetic field source provided outside the body is detected from a magnetic field detection value output from a linear medical instrument tip position detecting member that sets the magnetic sensor means at the tip position of the medical instrument. And a second step of detecting the position of the distal end of the medical instrument by displaying the magnitude of the magnetic field detected in the first step. A method for detecting the position of a medical instrument, comprising: . 14. A medical device having a locking member for suppressing insertion beyond a specified amount and a magnetic sensor means at a tip thereof, which is inserted into a tubular medical device used in a form in which a part is inserted into a body. A linear medical instrument tip position detecting member for setting the magnetic sensor means at the tip position of the medical instrument, and a prescribed value provided outside the body based on a detection value of the magnetic sensor means provided in the medical instrument tip position detecting member. A medical instrument set, comprising: a medical instrument tip position detection device that detects a tip position of the medical instrument by detecting a magnetic field generated by a magnetic field generation source. 15. A linear medical device insertion member used by being inserted into a tubular medical device used in a form in which a part is inserted into a body, and a medical device insertion member provided at a distal end of the medical device insertion member. A magnetic sensor unit for detecting a magnetic field; and a magnetic sensor unit disposed at the medical device insertion member for preventing insertion of the medical device insertion member beyond a specified amount, thereby setting the magnetic sensor device at a distal end position of the medical device. A member for detecting a distal end position of a medical device, comprising: a locking means. 16. A medical instrument tip position detecting device used for detecting a tip position of a tubular medical instrument used in a form in which a part is inserted into a body, a magnetic field generating source for generating a magnetic field, A linear medical device which is provided with a locking member for preventing insertion beyond a specified amount and a magnetic sensor means at the tip, and which is inserted into the medical instrument to set the magnetic sensor means at a tip position of the medical instrument; Input means for inputting a magnetic field detection value output by the tip position detecting member; and detecting the magnetic field generated by the magnetic field source from the detection value input by the input means, thereby detecting the tip position of the medical device. And a medical instrument tip position detecting means. 17. The medical instrument tip position detecting device according to claim 4, 8, 12, or 16, wherein the medical instrument tip position detecting means detects a tip position of the medical instrument by extracting a variation amount of a detection magnetic field. A medical instrument tip position detecting device. 18. The medical instrument tip position detecting device according to claim 4, wherein the medical instrument tip position detecting means extracts a prescribed frequency component from a detection value of the magnetic sensor means to generate a magnetic field. A medical instrument tip position detecting device for detecting a magnetic field generated by a source. 19. The medical instrument tip position detecting device according to claim 4,8, 12, or 16, wherein the medical instrument tip position detecting means subtracts a generated magnetic field of the surrounding environment detected in advance from a detection value of the magnetic sensor means. A medical instrument tip position detecting device characterized by detecting a magnetic field generated by a magnetic field generating source. 20. The medical instrument tip position detecting device according to claim 4, 8, 12, or 16, wherein two magnetic sensors having sensitivity axes in the same direction are provided, and the medical instrument tip position detecting means is A medical instrument tip position detecting device, characterized in that a magnetic field generated by a magnetic field generating source is detected using difference information of detection values of two magnetic sensor means.