JP6204673B2 - Magnetic fluid detector - Google Patents

Description

  The present invention relates to a magnetic fluid detection device for identifying an accurate position of a sentinel lymph node (SLN) using magnetic fluid injected into the body.

  Sentinel lymph node biopsy is one of the diagnosis of cancer metastasis in cancer treatment. This is a diagnostic method for diagnosing that if there is no metastasis in sentinel lymph nodes, there is no subsequent cancer metastasis to the lymphatic system. Therefore, if the sentinel lymph node is removed and examined, and no metastasis is found, the subsequent lymph node dissection site can be minimized.

  Conventionally, in breast cancer, a radioisotope drug that emits gamma rays and a blue dye are administered around the tumor, and before surgery, the gamma probe that is a gamma ray detector is used to find the approximate position of the sentinel lymph node, At the time of surgery, the sentinel lymph node was visually identified by staining with a pigment. However, in this method, since a radioisotope drug is used, there has been a problem that patients and medical workers are exposed to radiation. Another problem is that expensive equipment is required to handle radioisotope drugs.

  Therefore, there is a method of identifying the position of the sentinel lymph node by detecting the magnetic fluid injected around the tumor as a tracer. For example, Patent Document 1 proposes an apparatus using a magnetic fluid detection element composed of two or more magnetic sensors and excitation means. However, since the amount of the magnetic fluid staying in the sentinel lymph node is small, there is a problem that it is easily affected by geomagnetism and difficult to use in the operating room. In order to capture a magnetic signal emitted from an extremely small amount of magnetic fluid with high sensitivity, magnetic noise other than the magnetic signal from the magnetic fluid serving as a tracer must be effectively filtered.

Japanese Patent No. 4090722

  The present invention has been made based on such a problem, and an object of the present invention is to provide a magnetic fluid detection device capable of detecting magnetic fluid with high accuracy by effectively filtering magnetic noise. .

  The magnetic fluid detection device of the present invention includes one or more magnets that excite magnetic fluid staying in the body, a plurality of magnetic sensors that detect magnetic signals generated from the magnetic fluid excited by the magnets, and magnets, or , A vibration means for vibrating the magnet and the plurality of magnetic sensors, a reference signal generation unit made of a paramagnetic material disposed on the opposite side of the detection side of the magnetic sensor, and a difference between outputs from the plurality of magnetic sensors And a detecting means for detecting a fluid.

  According to the present invention, the magnet or the magnet and the magnetic sensor are vibrated, the magnetic signal emitted from the magnetic fluid excited by the magnet is detected by the magnetic sensor, and the difference between the outputs is taken. Can be detected. In addition, since the reference signal generation unit made of a paramagnetic material is arranged on the opposite side of the detection side of the magnetic sensor, the magnet or the magnet and the magnetic sensor are detected by the magnetic sensor detecting the reference signal generation unit. The detection signal synchronized with the vibration can be output. Therefore, magnetic noise can be effectively filtered and magnetic fluid can be detected with high accuracy.

It is a figure showing the whole structure of the magnetic fluid detection apparatus which concerns on one embodiment of this invention. It is a figure showing the internal structure of the magnetic fluid detection apparatus shown in FIG. It is a figure which expands and represents a part of FIG. It is a characteristic view showing the detection signal of a magnetic sensor when only a reference signal generation part is detected. It is a characteristic view showing the detection signal of a magnetic sensor when a reference signal generation part and a magnetic fluid are detected. FIG. 5 is a characteristic diagram showing a detection signal of a magnetic sensor when there is no magnetic fluid in a magnetically shielded ideal environment in a magnetic fluid detection device without a reference signal generation unit. FIG. 5 is a characteristic diagram showing a detection signal of a magnetic sensor when there is a magnetic fluid in an ideal environment where the magnetic fluid is shielded in a magnetic fluid detection device without a reference signal generation unit. FIG. 3 is an example of a characteristic diagram showing a detection signal of a magnetic sensor when there is no magnetic fluid in an environment where the magnetic fluid is not shielded in a magnetic fluid detection device without a reference signal generator. FIG. 10 is another example of the characteristic diagram showing the detection signal of the magnetic sensor when there is no magnetic fluid in an environment where the magnetic fluid is not shielded in the magnetic fluid detection device without the reference signal generation unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration of a magnetic fluid detection device 1 according to the present embodiment. FIG. 2 shows the internal configuration of the magnetic fluid detection device 1, and FIG. 3 shows an enlarged part thereof. The magnetic fluid detection device 1 is used, for example, when identifying a sentinel lymph node using a magnetic fluid injected into the body of a subject M as a tracer. A probe 10 and a control device connected to the probe 10 are used. 20.

  The probe 10 includes, for example, one or more magnets 11 that excite magnetic fluid staying in the body of the subject M, and a plurality of magnetic sensors 12 that detect magnetic signals generated from the magnetic fluid excited by the magnets 11. And a vibration means 13 for vibrating the magnet 11 and the plurality of magnetic sensors 12, and a storage body 14 for storing them. The probe 10 has a size that can be inserted into a body cavity, for example. The storage body 14 has, for example, a cylindrical shape that extends in one direction and is closed at the front end side and the rear end side, and is made of a medical resin such as polysulfone. For example, a handle 15 may be provided outside the storage body 14.

  For example, the magnet 11 and the magnetic sensor 12 are disposed on the distal end side of the housing body 14, and the distal end side of the housing body 14 is a side for detecting a magnetic fluid. For example, the magnetic sensors 12 are arranged side by side along the front end surface of the storage body 14, and the magnets 11 are arranged on the side opposite to the detection side of each magnetic sensor 12, that is, on the rear end side. . 2 and 3 show a case where there is one magnet and two magnetic sensors 12. The distance L1 between each magnetic sensor 12 and the front end surface of the storage body 14 is preferably set to about 0.1 mm to 0.5 mm, for example. The magnet 11 may be a permanent magnet or an electromagnet, and the magnetic sensor 12 is preferably composed of, for example, a magnetoresistive element (MR sensor), a coil-type magnetic sensor, a Hall-type magnetic sensor, or an MI-type magnetic sensor.

  For example, the vibration means 13 is extended in one direction, supports a magnet 11 and each magnetic sensor 12 on the front end side, supports the support body 13A rotatably on the rear end side, and supports the rear end side. It has the rotating part 13C which vibrates the magnet 11 and each magnetic sensor 12 by rotating as the fulcrum 13B. That is, the magnet 11 and each magnetic sensor 12 are configured to reciprocate in a circular arc around the fulcrum 13B, for example.

  The vibration direction of the magnet 11 and each magnetic sensor 12 is preferably the arrangement direction of each magnetic sensor 12, for example, the amplitude is in the range of 1 mm to 3 mm, for example, and the frequency is in the range of 5 Hz to 20 Hz, for example. It is preferable to be inside. The distance from the fulcrum 13B of the support 13A to the magnet 11 or each magnetic sensor 12 is preferably, for example, 200 mm to 400 mm, and between the distal end surface of the storage body 14 and the magnet 11 or each magnetic sensor 12 during vibration. The distance fluctuation amount L2 is preferably in the range of 0.005 mm to 0.01 mm, for example. The rotating portion 13C is configured to rotate the support 13A by, for example, a servo motor.

  Inside the probe 10, for example, a reference signal generator 16 made of a paramagnetic material such as iron is provided on the side opposite to the detection side of the magnetic sensor 12 and the magnet 11, that is, on the rear end side. By providing the reference signal generation unit 16, the magnetic sensor 12 detects the reference signal generation unit 16, is larger and more stable than geomagnetism and magnetic disturbance noise, and is synchronized with the vibration of the magnet 11 and the magnetic sensor 12. This is because the detected signal can be output. The reference signal generator 16 is preferably plate-shaped, for example, and is provided corresponding to the range of vibration of the magnetic sensor 12.

  The distance L3 between the reference signal generation unit 16 and the magnetic sensor 12 is, for example, that the resistance value of the magnetic sensor 12 when the reference signal generation unit 16 is disposed is such that the resistance value variable range of the magnetic sensor 12 is 500Ω to 1500Ω. When a sensor is used, it is preferable to be within a range of 510Ω to 512Ω. If the reference signal generator 16 is too close to the magnetic sensor 12, the resistance value of the magnetic sensor 12 is saturated and it becomes difficult to detect the magnetic fluid, and if it is too far, the detection signal of the reference signal generator 16 becomes small, This is because the effect of suppressing the influence of magnetic disturbance noise is reduced.

  For example, the control device 20 is connected to the probe 10 by a connection cable 21, and the vibration control means 22 for controlling the vibration of the magnet 11 and the magnetic sensor 12, and the difference between the outputs from the magnetic sensors 12, takes the magnetic fluid. It has the detection means 23 to detect, and the display means 24 which displays the detection result by the detection means 23. It is preferable that the control device 20 further includes a voice notification unit that conveys the detection result by voice.

  In this magnetic fluid detection device 1, for example, the magnetic fluid injected into the body of the subject M by causing the tip of the probe 10 to approach the subject M into which the magnetic fluid has been injected and causing the magnet 11 and the magnetic sensor 12 to vibrate. Is detected. When the magnetic fluid does not stay, the magnetic sensor 12 detects only the reference signal generator 16, and for example, as shown in FIG. 4, the reference signal generator is synchronized with the motion of the magnetic sensor 12. 16 detection signals are output. In addition, when the magnetic fluid is stagnant, the magnetic sensor 12 detects the reference signal generator 16 and the magnetic fluid, and can be synchronized with the motion of the magnetic sensor 12, for example, as shown in FIG. The detection signal of the reference signal generator 16 and the magnetic fluid detection signal are added and output. Therefore, the detection signal when only the reference signal generator 16 is detected is used as a reference signal, and the amount of detection signal larger than this reference signal (the amount of detection waveform amplitude is increased) is detected as a magnetic fluid. Magnetic fluid is detected as a signal.

  In the absence of the reference signal generator 16, if there is no magnetic fluid in an ideal environment where the magnetic shield is provided, a detection signal is output from the magnetic sensor 12, for example, as shown in FIG. If the magnetic fluid is not in front of the magnetic sensor 12, a detection signal synchronized with the movement of the magnetic sensor 12 is output, for example, as shown in FIG. The magnitude of the output increases according to the magnetic strength of the magnetic fluid. On the other hand, in an environment without a magnetic shield, even if there is no magnetic fluid, if there is no reference signal generator 16 due to the influence of geomagnetism or disturbance magnetic noise, for example, as shown in FIG. 8 or FIG. As described above, a detection signal is output from the magnetic sensor 12. In a state where such magnetic noise is received, even if there is a magnetic fluid in front of the magnetic sensor 12, it is difficult to detect the magnetic fluid. This is because the phase of the detection signal and the shape of the waveform change depending on the magnetic fluid, but the amplitude of the detection waveform does not necessarily increase.

  However, even when there is magnetic noise as described above, if the detection signal of the magnetic noise is synchronized with the motion of the magnetic sensor 12, the waveform height when the magnetic fluid is detected becomes the waveform height of the magnetic noise. Since the waveform height of the magnetic fluid is added, the waveform height of the magnetic fluid can be obtained by subtracting the magnetic noise. In this magnetic fluid detection device 1, a reference signal generation unit 16 is provided in the vicinity of the magnetic sensor 12, and the magnetic sensor 12 always detects the reference signal generation unit 16, so that it is more stable than geomagnetism and magnetic disturbance noise. In addition, a reference signal synchronized with the motion of the magnetic sensor 12 is generated, and the influence of geomagnetism and disturbance magnetic noise generated from a position farther than the reference signal generator 15 is suppressed.

  As described above, according to the present embodiment, the magnet 11 and the plurality of magnetic sensors 12 are vibrated, the magnetic signals emitted from the magnetic fluid excited by the magnet 11 are detected by the plurality of magnetic sensors 12, and the difference between the outputs is calculated. Since it was made to take, magnetic fluid can be detected. In addition, since the reference signal generation unit 16 made of a paramagnetic material is disposed on the opposite side of the detection side of the magnetic sensor 12, the magnetic sensor 12 detects the reference signal generation unit 16, whereby the magnet 11 and the magnetic sensor 12 are magnetic. A detection signal synchronized with the vibration of the sensor 12 can be output. Therefore, magnetic noise can be effectively filtered and magnetic fluid can be detected with high accuracy.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the case where the magnet 11 and the magnetic sensor 12 are vibrated has been described, but only the magnet 11 may be vibrated.

  It can be used for identification of sentinel lymph nodes using a magnetic fluid injected into the body as a tracer.

  DESCRIPTION OF SYMBOLS 1 ... Magnetic fluid detection apparatus, 10 ... Probe, 11 ... Magnet, 12 ... Magnetic sensor, 13 ... Vibrating means, 13A ... Supporting body, 13B ... Supporting point, 13C ... Rotating part, 14 ... Storage body, 15 ... Handle, 16 ... Reference signal generator, 20 ... control device, 21 ... connection cable, 22 ... vibration control means, 23 ... detection means, 24 ... display means

Claims (1)

One or more magnets that excite magnetic fluid staying in the body;
A plurality of magnetic sensors for detecting magnetic signals generated from the magnetic fluid excited by the magnet;
Vibration means for vibrating the magnet or the magnet and the plurality of magnetic sensors;
A reference signal generator made of a magnetic material disposed on the side opposite to the detection side of the magnetic sensor;
Detecting means for detecting a magnetic fluid by taking a difference between outputs from the plurality of magnetic sensors;
The magnet, the plurality of magnetic sensors, the vibration means, and the reference signal generator are stored in a storage body that is extended in one direction,
The plurality of magnetic sensors are arranged side by side along the front end surface of the storage body,
The magnet is disposed on a side opposite to a detection side of the plurality of magnetic sensors;
The reference signal generator is disposed on the opposite side to the detection side of the plurality of magnetic sensors and the magnet,
The magnetic fluid detection device, wherein the magnetic sensor always detects the reference signal generator .

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