JP3960558B1 - Magnetic fluid detector and detector - Google Patents

Abstract

A magnetic fluid administered into a body is detected with high sensitivity.
A detector 1 for detecting a magnetic fluid administered into a body, the detector 1 being symmetrical with a magnetic sensor 4 having a polarity with a north pole facing a detection direction. A rare earth magnet 7 arranged at an angle of 180 degrees around the center as a center and arranged in the same relationship as the polarity of the magnetic sensor 4 and a cylindrical shape with both bottoms open, and the rare earth magnet 7 is exposed from the cylinder end. And a covering 6 made of a magnetic alloy having a high magnetic permeability that is accommodated so as not to be damaged.
[Selection] Figure 3

Description

The present invention belongs to the technical field of the detector contact and the detection device of the magnetic fluid used in detecting magnetic fluid injected into the body of the subject (body cavity).

Today, malignant tumors typified by cancer are known to metastasize through the lymphatic vessels of tumor cells present in the lesion, and if tumors are found there, the tumor cells that have entered the lymphatic vessels The sentinel lymph node (Sentinel Lymph Node), which has reached, is identified, and at the time of surgery, the identified sentinel lymph node is removed together with the lesion, and the unreached lymph node is not removed Surgical techniques have been attempted to reduce the burden on patients by leaving them as they are.
As a specific technique for sentinel lymph nodes to which such tumor cells have metastasized, a technique using near-infrared excitation light has been proposed (see, for example, Patent Document 1), which is a tracer such as indocyanine green. When an appropriate amount of time has passed after injecting the infrared fluorescent dye into the lesion, performing an laparotomy and irradiating the observation site with near-infrared excitation light causes the infrared fluorescent dye accumulated in the sentinel lymph nodes to be in the near infrared. The sentinel lymph node can be identified by emitting light and visualizing it. However, this is not only low in the body permeation of near-infrared excitation light itself, but is often disturbed by things like fat and spear deposits in the lungs, and sentinel from the surface to a depth of several millimeters at most. There is a problem that only the lymph nodes can be detected, and the reliability of detection accuracy is lacking.
On the other hand, a radioisotope (RI) is injected into a lesion, and after an appropriate time has passed, a sentinel lymph node in which the injected radioisotope is accumulated is detected and identified using a radiation detector such as a Geiger counter. (See, for example, Patent Documents 2 and 3). However, this is not only because the patient is directly exposed to the body due to the injected radioisotope, but also it is necessary to work in a completely sealed radiation control room, and the construction and maintenance of such a control room is necessary. In addition, the management of radioisotopes can only be done in large hospitals that are virtually equipped, and it is difficult to implement in small and medium-sized hospitals.
Thus, recently, a magnetic fluid is injected into a lesioned part, and a sentinel lymph node in which the injected magnetic fluid is accumulated is detected by a magnetic detection device after an appropriate time has passed (for example, Patent Document 4). reference).
JP 2001-299676 A JP-A-9-189770 JP-A-10-96782 Japanese Patent No. 3847694

By the way, the magnetic detection device includes a pair of magnetic sensors on the front end surface of the exciting magnet, and detects a change in the magnetic field when the magnetic fluid is magnetized by the exciting magnet. There will be those magnetic flux density is low as the excitation magnet for magnetically saturated (magnetic flux density reaches the detection limit) is adopted an electromagnet as the exciting magnets not to, Therefore inevitably detection sensitivity is low, as the sentinel lymph node In order to detect, there is a problem that a large amount of ferrofluid must enter the lymph nodes.
In addition, the magnetic sensor is configured such that one magnetic sensor detects magnetic fluid and the other magnetic sensor does not detect magnetic fluid. The difference between detection values of both magnetic sensors at this time is taken, and based on this difference. Detection of the presence of magnetic fluid, that is, one magnetic sensor is in a magnetic fluid detection state and the other magnetic sensor is in a magnetic fluid non-detection state and is applied to a lymph node, and detection by both magnetic sensors The magnetic fluid is detected based on the output difference. For this reason, detection is possible when the magnetic fluid is in a position biased to one of the magnetic sensors, but the detected value becomes the same as the magnetic fluid approaches the central position between the two magnetic sensors, so the difference becomes smaller. This phenomenon occurs, and when it is located at the central position, it is practically impossible to detect, and there is a problem that the detection of the sentinel lymph node is unstable and the detection accuracy is poor, and there is a problem that the present invention does not solve .

The present invention was created for the purpose of solving such problems, and the invention of claim 1 is a detector for detecting a magnetic fluid administered into the body, the detector comprising: A magnetic sensor having a polarity in which either the N pole or the S pole is directed in the detection direction, and the magnetic sensor is symmetrically arranged around the magnetic sensor with the center of symmetry being the same as the polarity of the magnetic sensor A plurality of or cylindrical magnets arranged in a magnetic relationship, and a cylindrical shape having an opening in the detection direction and the opposite side, and formed of a magnetic material having a magnetic permeability for accommodating the magnet so as not to be exposed from the end of the cylinder When the magnet is in a non-detection state, when the magnet is exposed from the cylindrical end of the magnetic material, the magnetic field lines from the magnet reach the magnetic sensor to bring the magnetic sensor to a detection limit state. Has a magnetic force to saturate That is, the detector of the magnetic fluid, wherein the magnetic field lines by accommodating so as not to be exposed from the cylinder end is set so as not to reach to the magnetic sensor.
The invention of claim 2 is a detection device for detecting a magnetic fluid administered into the body, wherein the detection device is one magnetic sensor having a polarity in which either the N pole or the S pole is directed in the detection direction. A plurality of or cylindrical magnets arranged symmetrically around the magnetic sensor with the magnetic sensor as the center of symmetry, and arranged in the same magnetic relationship as the polarity of the magnetic sensor, and the detection direction and the opposite side are open And a detector formed of a magnetic material having a magnetic permeability that accommodates the magnet so that the magnet is not exposed from the end of the cylinder, and amplifies the detection value detected by the detector and amplifies the amplified detection And a controller that outputs a comparison detection value and reports the value by comparing the value with the origin, and when the magnet is in the non-detection state, the magnet is exposed from the cylinder end of the magnetic material. The magnetic field lines of the magnetic field reach the magnetic sensor and Has a magnetic force to saturate in the state of the detection limit of the capacitors, the detection device of the magnetic fluid, wherein the magnetic field lines by accommodating so as not to be exposed from the cylinder end is set so as not to reach the magnetic sensor It is.

  The present invention has such a configuration that the magnetic lines of force generated from the magnet are accommodated so that the magnet does not protrude from the covering made of a magnetic permeability material, and is thus focused toward the detection direction. As a result, the magnetic sensor can be maintained in a state that does not cause magnetic saturation, and detection of magnetic fluid in the body cavity can be performed. It can be performed with high accuracy, and detection of sentinel lymph nodes to which cancer cells have metastasized can be performed while being simple.

Next, a first embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a magnetic fluid detector. The detector 1 has a cylindrical body 3 projecting from a grip 2, and a magnetic sensor 4 for magnetic detection is provided at the tip of the cylindrical body 3. However, the magnetic sensor 4 is configured by using one Hall element as apparent from FIG . In this case, the magnetic sensor 4 is arranged so that the tip side is an N pole. Further, wiring (detection signal wiring and power supply wiring) 5 connected to the magnetic sensor 4 is drawn out from the base end of the cylindrical body 3 to the outside. Further, on the outer peripheral surface of the distal end portion of the cylindrical body 3, a cylindrical covering body 6 formed of a high permeability magnetic alloy (for example, permalloy, super permalloy, and supermalloy (all trade names)) is provided. However, the covering 6 is arranged in a symmetric state with the magnetic sensor 4 as a symmetric center in a state of surrounding the plurality of magnetic sensors 4. In the present embodiment, two covering bodies 6 are provided. In this case, the covering bodies 6 are opposed to each other with the magnetic sensor 4 interposed therebetween, that is, an angle of 180 degrees with the magnetic sensor 4 as the center. Is arranged. For this reason, for example, if three covering bodies are provided, the angle is 120 degrees, and if four covering bodies are used, 90 degrees is provided around the magnetic sensor 4 at an equal angle. Thus, the magnetic symmetry centered on the magnetic sensor is maintained.

  The covering 6 contains a superferromagnetic rare earth magnet 7 having high magnetic properties (residual magnetic flux density (Br), coercive force (bHc, iHc), maximum energy product (BHmax), etc.). Here, as the rare earth magnet 7, a general-purpose magnet manufactured using rare earth elements samarium (Sm) or neodymium (Nd) can be employed. The rare-earth magnet 7 is set in a state in which the tip does not protrude from the tip of the covering body 6, that is, in a state where it is slightly recessed with respect to the tip of the covering body 6. In this embodiment, the rare earth magnets 7 are sealed in the covering 6 so that the tip side is an N pole.

  A controller 8 supplies power to the magnetic sensor 4 and processes a detection signal detected by the magnetic sensor 4. The controller 8 is provided with an input / output interface 9 to which the wiring 5 is connected. The controller 8 itself is driven by the power supplied from the power supply circuit 10, and the power is supplied to the magnetic sensor 4 via the input interface 9. The input / output interface 9 is connected to an amplifying circuit 11 for amplifying the detection signal detected by the magnetic sensor 4. The amplified detection signal amplified by the amplifying circuit 11 passes through a low-pass circuit 11a and is compared with a comparison circuit. The comparison circuit 12 compares the origin signal set by the origin (zero point) adjustment circuit 13 with the amplification detection signal, and uses the difference as a difference detection signal for A / D. Output to the conversion circuit 14. Then, the converted difference detection signal is output to the neglecting unit 15 and a notification corresponding to the difference is made. As a notification means, a sound level change such as a buzzer sound, and a blinking time of the housing are short and long. One type or a plurality of types that can be recognized by hearing or vision, such as changes, changes in intensity of the light intensity of the housing, and changes in the pointer position by an ammeter or voltmeter, can be employed. Furthermore, it may be possible to store the information if necessary, and of course, these notification signals may be output to the outside.

[Experiment 1] Performance Confirmation Experiment of Detector 1 In order to confirm the effect of the present invention, a magnetic material (iron piece) 16 is used as a magnetic fluid, and iron sand is used to visualize a change in magnetic flux. Was covered with a transparent resin plate, the sand iron was placed on the upper surface of the transparent resin material in front of the detector 1, and the magnetic material 16 was placed on the resin material to conduct the following experiment. The state is shown in FIGS. 3A is a state of sand iron when the magnetic sensor 4 is turned on, FIG. 3B is a state of sand iron when the magnetic material 16 is brought close to the front of the magnetic sensor 4, FIG. (C) shows a state of iron sand when the magnetic material 16 is brought close to the front surface of one rare earth magnet 7. According to this, the thing of FIG. 3 (A) without the magnetic material 16 is concentrated in a bundle on the tip N pole and the base end S pole of the rare earth magnet 7, but especially on the tip of the tip N pole. The bundled magnetic flux is elongated in the direction ahead and spreads in the left-right direction at the tip, and there is little iron sand near the front of the magnetic sensor 4, and the iron sand is at the tip. Something connected was observed. This indicates that a blank area where the magnetic field lines from the rare earth magnet 7 do not reach is formed in the vicinity of the front surface of the magnetic sensor 4. The distance and size of the blank area in front of the magnetic sensor 4 can be adjusted by the angle of the magnet with respect to the magnetic sensor 4, the combination of the covering and the magnet, or the like. Further, there is only a small amount of iron sand around the covering 6, so that the magnetic lines of force from the rare earth magnet 7 are concentrated in a bundle from the base end and the distal end of the covering 6. It can be seen that at 6, the magnetic field lines are absorbed and do not go outside. In this state, the origin adjustment circuit 13 provided in the controller 8 is adjusted to a non-notification state.

  From this state, when the magnetic material 16 was arranged in front of the magnetic sensor 4, it was observed that the bundle of sand iron changed in an arch shape from the left and right rare earth magnets 7 to the magnetic material 16. It was observed that a flow of sand iron reaching the magnetic sensor 4 occurred, that is, a magnetic flux was generated in the blank area. At this time, the controller 8 gives notification that the presence of the magnetic material 16 has been strongly detected. This is presumed that the magnetic material 16 is charged to the south pole due to the approach to the rare earth magnet, and a magnetic flux is generated between the south pole and the north pole of the magnetic sensor 4, and this is detected as a change in magnetic field lines. Is done. This is the same state when the magnetic material 16 is arranged in front of one of the rare earth magnets 7, that is, when it is biased from the magnetic sensor 4, and the presence of the magnetic material is detected.

  Next, an experiment on the function of the covering 6 was performed. 4 (A) and 4 (B) are the magnetic materials in the state in which the covering 6 is retracted from the magnetic sensor 4 and the tip of the rare earth magnet 7 protrudes from the covering 6 (see FIG. 4 (C)). 4 and FIG. 4A without the magnetic material 16 are those in which the iron sand is close to the periphery of the exposed rare earth magnet 7. As shown in FIG. 3A, the iron sand bundle did not reach far (the origin was adjusted in this state). When the magnetic material 16 was brought close to this, a bundle of sand iron from the rare earth magnet 7 to the magnetic material 16 was observed, but no flow of sand iron from the magnetic material 16 to the magnetic sensor 4 was observed. In this case, the controller 8 could not detect the presence of the magnetic material 16. This is because, by exposing the rare earth magnet 7, the magnetic field lines from the exposed rare earth magnet 7 reach the magnetic sensor 4, and as a result, the magnetic sensor 4 is in a state before the magnetic material 16 is brought closer. However, when the magnetic material 16 is brought close to the magnetic material 16 in this state, the magnetic field lines from the rare earth magnet 7 reach the magnetic material 16, but the magnetic sensor 4 is in a state without the magnetic material 16. Since it is already saturated, there is no generation of magnetic lines from the magnetic sensor 4 to the magnetic material 16 even when the magnetic material 16 is brought closer as shown in FIG. 4B, and therefore a magnetic change could not be detected. Estimated.

Then, next, when the tip of the rare earth magnet 7 was positioned flush with the tip of the covering 6 was examined, the rare earth magnet 7 shown in FIG. Although it was confirmed that the detection sensitivity was slightly lower than that obtained, it was confirmed that practical detection was possible. The reason why the detection sensitivity is lower than the depth of the rare earth magnet 7 is that the rare earth magnet 7 is flush with the covering 6, so that the magnetic lines of force from the rare earth magnet 7 slightly saturate the magnetic sensor 4. It is presumed that worked. For these reasons, the rare earth magnet 7 protruding from the covering 6 cannot detect the magnetic body 16 satisfactorily, and it is necessary to be flush with the tip of the covering 6 or be in the back. confirmed.
Furthermore, when the covering 6 was examined by covering the base end with a magnetic alloy having the same high magnetic permeability, as shown in FIG. 3, there was almost no bundle of sand iron on the S pole side, as shown in FIG. The detection sensitivity of the magnetic body 16 was low. This is presumably because the magnetic field lines from the N pole to the S pole of the rare earth magnet 7 covered with the covering 6 are disturbed. Further, although the case where the tip of the magnetic sensor 4 is set to the S pole and the tip of the rare earth magnet 7 is left as the N pole has been studied, this is the case where the magnetic sensor 16 is removed from the rare earth magnet 7 without the magnetic material 16. A thick bundle of iron sand was observed, and the sand iron bundle was hardly changed even when the magnetic material 16 was brought close to it, and there was no detection reaction of the magnetic material 16. This is presumably because the magnetic sensor is already saturated without the magnetic material 16.

  From these results, it is assumed that the detector 1 employs a cylindrical covering 6 made of a high permeability magnetic alloy and has both bottom surfaces open, and the rare earth magnet 7 does not protrude from the covering 6. In addition, it was confirmed that the magnetic sensor 4 is preferably arranged so as to have the same polarity as that of the rare earth magnet 7.

[Experiment 2] Living Body Confirmation Experiment Next, an investigation was made as to whether or not magnetic fluid could actually be detected in the living body. The magnetic fluid for carrying out the present invention is one that minimizes the influence on the human body. For example, there is a contrast agent for MRI (for example, “Resovist” (registered trademark)). This consists of a liquid containing superparamagnetic iron oxide fine particles. After such magnetic fluid is injected into the affected area, as the time passes, the magnetic fluid flows into the lymph nodes through the lymphatic vessels and accumulates. Next, an experiment was conducted using female mice as experimental organisms.

  Using the contrast medium as a magnetic fluid, 0.1 ml was injected into the right shoulder (upper arm) of the mouse with a syringe, and after 2 hours, the mouse was incised and placed under the arm, with the detector 1 targeting the cervical lymph node When the magnetic fluid was detected using this, a strong presence reaction of the magnetic material was obtained from the lymph node on the right side, and the presence of the magnetic fluid was confirmed. A slight reaction was also observed in the left lymph node.

Next, the magnetic fluid was administered in the vicinity of the fourth mammary gland on the right side of the mouse, and after 2 hours, measurement was performed targeting the inguinal lymph node. Although the magnetic fluid has spread greatly under the skin because the ferrofluid has not spread to the lymph node, it has responded well to external measurements and post-incision measurements using the detector 1, and The existence was confirmed.
Next, the magnetic fluid was administered between the fingers of the right or left lower limbs, and measurement was performed 2 hours later with the inguinal lymph node as a target. This was able to detect magnetism in the inguinal lymph nodes on the side administered with magnetic fluid.

Next, a second embodiment of the detector created using the ferrite magnet 17 will be described with reference to FIG. The ferrite magnet 17 used here has a cylindrical shape, and the magnetic sensor 4 is accommodated in the inner periphery via the inner cylinder 18 formed of the magnetic alloy having the high magnetic permeability, and the outer periphery is also formed of the magnetic alloy. In this case, the ferrite magnet 17 has a tip that does not protrude from the inner and outer cylinders 18 and 19. By doing so, the ferrite magnet 17 is magnetic. The sensor 4 is arranged symmetrically around the magnetic sensor 4 with the sensor 4 as the center of symmetry, and the ferrite magnet 17 surrounds the outer periphery of the magnetic sensor 4 in a cylindrical shape and has a large magnetic flux density. However, the magnetic field lines in this case are cylindrical and reach the front, but do not reach the magnetic sensor 4. In the present embodiment, the detector is accommodated in a casing 20 having a bowl shape (semi-oval shape) that is easy to grasp in a state where magnetic lines of force emerge from the bottom plane, and in the state of gripping the casing 20, the magnetism in the body cavity The fluid can be detected. Reference numeral 21 denotes a support member for supporting the magnet 17 and the sensor on the casing 20.

  When the detection experiment of the magnetic body 16 was performed using this detector, the magnetic body 16 was detected as in the case of the first embodiment. In this case, the detection was performed by sliding the bottom surface of the casing. As a result, the parallelism can be maintained, and the detector does not tilt as in the first embodiment. As a result, the position of the magnetic body 16 can be detected more accurately. There is convenient.

  Needless to say, the present invention is not limited to the above-described embodiment, and the magnet is not limited to a rare earth magnet or a ferrite magnet, and a ferromagnetic magnet such as an alnico magnet is appropriately employed as necessary. be able to.

It is a partial cross section front view of a detector. It is a schematic block diagram of a detection apparatus. The flow of sand iron when the rare earth magnet is immersed in the coated body is shown, where (A) shows no magnetic material and (B) shows the magnetic material positioned in front of the magnetic sensor. State (C) is an explanatory view showing a state in which the magnetic material is biased toward one rare earth magnet. The rare earth magnet is projected from the cover, (A) shows the flow of sand iron when no magnetic material is present, and (B) is the magnetic material in front of the magnetic sensor. The flow of sand iron when it is in a positioned state, (C) is an explanatory view showing a state without sand iron. (A) and (B) are the bottom view and longitudinal cross-sectional view of the detector of 2nd embodiment.

DESCRIPTION OF SYMBOLS 1 Detector 4 Magnetic sensor 6 Covering body 7 Rare earth magnet 8 Controller

Claims (2)

A detector for detecting a ferrofluid administered into the body, the detector comprising:
One magnetic sensor having a polarity in which either the N pole or the S pole faces in the detection direction;
A plurality of or cylindrical magnets arranged symmetrically around the magnetic sensor with the magnetic sensor as the center of symmetry, and arranged in the same magnetic relationship as the polarity of the magnetic sensor;
It has a cylindrical shape with an opening in the detection direction and the opposite side, and is configured using a covering formed of a magnetic material having a magnetic permeability so that the magnet is not exposed from the end of the cylinder ,
When the magnet is in a non-detection state, when it is exposed from the cylinder end of the magnetic material, the magnetic force line from the magnet reaches the magnetic sensor and has a magnetic force that saturates the magnetic sensor to a detection limit state, but is exposed from the cylinder end. The magnetic fluid detector is configured so that the magnetic field lines do not reach the magnetic sensor by being housed so as not to be . A detection device for detecting a magnetic fluid administered into the body,
The detection device comprises:
One magnetic sensor having a polarity in which either the N pole or the S pole faces in the detection direction;
A plurality of or cylindrical magnets arranged symmetrically around the magnetic sensor with the magnetic sensor as the center of symmetry, and arranged in the same magnetic relationship as the polarity of the magnetic sensor;
A detector formed of a magnetic material having a cylindrical shape in which a detection direction and the opposite side are open and having a magnetic permeability so that the magnet is not exposed from the end of the cylinder;
It is configured using a controller that amplifies the detection value detected by the detector, compares the amplified detection value with the origin, outputs a comparison detection value, and notifies the same .
When the magnet is in a non-detection state, when it is exposed from the cylinder end of the magnetic material, the magnetic force line from the magnet reaches the magnetic sensor and has a magnetic force that saturates the magnetic sensor to a detection limit state, but is exposed from the cylinder end. An apparatus for detecting a magnetic fluid, wherein the magnetic fluid lines are set so as not to reach the magnetic sensor .

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