JP4163605B2 - Magnetic fluid detection device - Google Patents

Description

  In the present invention, as a basis for identifying a sentinel lymph node (Sentinel Lymph Node), which is a lymph node to which tumor cells that have entered the lymphatic vessels from the primary tumor site first arrive, The present invention relates to a magnetic fluid detection device for measuring how it is distributed after a predetermined time.

In recent years, resection surgery for early cancer is frequently performed because the detection rate of early cancer has improved. In general, surgery for early cancer is performed for the purpose of radical cure. Therefore, in addition to a lesioned part, a plurality of lymph nodes that are suspected of metastasizing around the lesioned part are often removed. In early cancer surgery, pathological examination of lymph nodes removed after surgery is performed, and the presence or absence of cancer metastasis to the lymph nodes is confirmed to determine the postoperative treatment policy.
Whether or not cancer has spread to lymph nodes at the surgical stage is unknown. For this reason, since surgery for early cancer removes a plurality of lymph nodes in the vicinity of a lesion, the burden on the patient is large.

  In recent years, there has been a demand for both patient QOL (Quality of Life) and curability in cancer resection surgery. As one of the techniques, Sentinel Node Navigation Surgery, which prevents unnecessary lymph node excision without cancer metastasis, has attracted attention. The sentinel node navigation surgery will be briefly described below.

  When cancer metastasizes to a lymph node, recent studies have revealed that it does not metastasize randomly but metastasizes from a lesion through a lymphatic vessel to a lymph node according to a certain pattern. When cancer has spread to lymph nodes, it is considered that there is always metastasis to sentinel lymph nodes. Here, the Sentinel Lymph Node (SN) is a lymph node to which cancer cells that have entered the lymphatic vessels from the primary cancer focus first arrive.

  For this reason, in early cancer surgery, it is possible to determine the presence or absence of cancer metastasis to lymph nodes by finding sentinel lymph nodes during biopsy and performing biopsy and rapid pathological examination. If cancer has not spread to the sentinel lymph nodes, early cancer surgery does not require removal of the remaining lymph nodes. On the other hand, when cancer has metastasized to the sentinel lymph node, the operation for early cancer involves excision of a plurality of lymph nodes in the vicinity of the lesion according to the metastatic state.

In early cancer surgery, by performing the sentinel node navigation surgery, in patients with no cancer metastasis to lymph nodes, unnecessary lymph node excision without cancer metastasis is not performed. The burden is reduced. The sentinel node navigation surgery is not limited to breast cancer, for example, and is also applied to open surgery such as a digestive organ or surgery using a laparoscope.
In this sentinel node navigation surgery, there is a strong demand for a detection device that can easily and accurately detect sentinel lymph nodes.

  Examples of the detection device include Japanese Patent Publication No. 2001-299676, Japanese Patent Publication No. 9-189770, Japanese Patent Publication No. 10-96782, US Pat. No. 6,205,352. Etc. are proposed.

  In recent years, SQUID magnetometers using superconducting quantum interference devices (hereinafter abbreviated as SQUIDs) have been applied in various fields. The SQUID can detect a magnetic flux of about one billionth of the geomagnetism with high sensitivity.

In recent years, as the SQUID, a high-temperature superconducting SQUID that can be used for cooling at a liquid nitrogen temperature (77.3 K: −196 ° C.) has been put into practical use.
Using this, the detection device is, for example, as described in a special issue of the Japanese Journal of Biomagnetic Science (Vol.15 No.1 2002 17th, P.31-32) An apparatus using a high-temperature superconducting SQUID has been proposed.

  In the detection method using the high-temperature superconducting SQUID, for example, as shown in FIG. 27, a magnetic fluid 102 having magnetism as a tracer is locally injected around the tumor by an injection means 101 such as a puncture needle. Then, after a predetermined time, the magnetic fluid 102 stays in the sentinel lymph node SN. FIG. 27 is an explanatory view showing the movement of the magnetic fluid when the magnetic fluid is used as the tracer.

Here, the detection device detects a sentinel lymph node by magnetizing the magnetic fluid with an electromagnet having a large magnetic force and detecting the weak residual magnetic field remaining in the magnetic fluid with the SQUID when the electromagnet is turned off. Is possible.
The magnetic fluid has a particle size as small as several hundred nm, so that the coercive force is weak and the residual magnetic field is very small. For this reason, a highly sensitive magnetic sensor such as SQUID is required.

  However, since the magnetic sensor formed by the high-temperature superconducting SQUID (hereinafter referred to as SQUID magnetic sensor) is operated at a low temperature of about −190 ° C., the sensor must be cooled using liquid nitrogen. For this reason, the detection method using the high-temperature superconducting SQUID is large in size and has poor operability. In addition, the detection method using the high-temperature superconducting SQUID needs to replace liquid nitrogen every few hours, which requires a running cost. Furthermore, the detection method using the high-temperature superconducting SQUID has problems such as danger associated with replacement of liquid nitrogen. In addition, the detection method using the high-temperature superconducting SQUID has a very small residual magnetic field of the magnetic fluid, so the influence of magnetic noise from the electrical equipment is large, and it is necessary to shield the magnetic field. Become.

On the other hand, the detection device described above is, for example, a device that detects the magnetic fluid using a plurality of magnetic sensors such as a Hall element and a magnetoresistive element as described in JP-A-2003-128590. Proposed.
The magnetic fluid detection device described in the above Japanese Patent Application Laid-Open No. 2003-128590 applies an excitation magnetic field to the magnetic fluid by an excitation means such as an excitation magnet, and the magnetic field strength of the same magnetic field direction component orthogonal to the excitation magnetic field is obtained. After detecting by the plurality of magnetic sensors and taking the difference between the outputs from the plurality of magnetic sensors, signal processing is performed to detect distortion (spatial magnetic gradient) of the local magnetic field distribution due to the magnetic fluid excited by the excitation means. It is supposed to be.
JP 2001-299676 A JP-A-9-189770 JP-A-10-96782 US Pat. No. 6,205,352 JP 2003-128590 A Japanese Biomagnetic Journal Special Issue Vol. 15 No. 1; Japanese Biomagnetic Journal, 2002, 17th, p. 31-32

However, the magnetic fluid detection device described in the above-mentioned Japanese Patent Application Laid-Open No. 2003-128590 uses a magnetic sensor such as a Hall element or a magnetoresistive element that can obtain an output proportional to the strength of the magnetic field. The magnetic field change due to the magnetic fluid is very weak compared to the excitation magnetic field generated by the excitation magnetic field. For this reason, if the output from the magnetic sensor is DC amplified, the amplifier output will be saturated, and therefore it must be AC amplified.
However, when the magnetic sensor is AC-coupled with a capacitor or the like, the signal change due to the magnetic fluid is attenuated unless the magnetic field change due to the magnetic fluid is very fast.

For this reason, the magnetic fluid detection device described in Japanese Patent Application Laid-Open No. 2003-128590 cancels a signal generated by the excitation magnetic field generated by the excitation magnetic field by taking a difference between a plurality of magnetic sensors, and only changes the signal due to the magnetic fluid. Is amplified.
Therefore, since the magnetic fluid detection apparatus described in JP-A-2003-128590 uses a plurality of the magnetic sensors, the detection site including the plurality of magnetic sensors is large and difficult to operate, and costs are high.

In addition, in the magnetic fluid detection device described in JP-A-2003-128590, when the excitation magnetic field generated by the excitation magnetic field is increased in order to increase the detection sensitivity of the magnetic fluid, the output of the magnetic sensor is saturated. As a result, a change in the magnetic field due to the magnetic fluid cannot be detected.
In addition, since the weak magnetic sensor output is amplified with high gain, when the sensor is vibrated, changes in the contact resistance of the lead wires are superimposed on the sensor output as noise, resulting in low magnetic fluid detection sensitivity. .

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic fluid detection device that is small in size, has good operability, and has high magnetic fluid detection sensitivity.

A first ferrofluid detection device according to the present invention is a ferrofluid detection device for detecting a ferrofluid staying in a subject, an excitation means for generating an excitation magnetic field for exciting the magnetic fluid, A coil for detecting distortion of a local magnetic field distribution caused by the magnetic fluid excited by the excitation magnetic field of the excitation means; and a preamplifier for amplifying the output from the coil, the excitation means, the coil and the preamplifier being integrated. It is characterized by vibration.
According to the second magnetic fluid detection device of the present invention, in the first magnetic fluid detection device, vibration means for integrally vibrating the excitation means, the coil and the preamplifier, and vibration of the vibration means are controlled. And a control unit for detecting the vibration frequency component from the output of the coil amplified by the preamplifier based on the operating state of the vibration means and notifying the signal intensity according to the detection result. It is characterized by.
According to a third magnetic fluid detection device of the present invention, in the second magnetic fluid detection device, the vibration means is a non-magnetic material that can vibrate by providing the excitation means, the coil, and the preamplifier at a tip portion. A vibration member; and a drive unit that vibrates the vibration member. The control unit controls and drives the drive unit to vibrate the vibration member, and outputs the coil based on the operating state of the drive unit. The vibration frequency component is detected from

  The magnetic fluid detection device of the present invention has an effect that it is small in size, has good operability, and has high magnetic fluid detection sensitivity.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 19 relate to a first embodiment of the present invention, FIG. 1 is an explanatory view showing a magnetic fluid detection device of the first embodiment of the present invention, and FIG. 2 is a diagram when the probe exterior member of FIG. 1 is removed. FIG. 3 is a schematic view of the probe main body of FIG. 2, FIG. 4 is a schematic explanatory view of the magnetic fluid detection device of FIG. 1, and FIG. 4 (A) is a schematic view of the magnetic fluid detection device of FIG. 4 is a schematic explanatory diagram, FIG. 4B is a schematic explanatory diagram showing a modification of FIG. 4A, FIG. 5 is a circuit block diagram of the control unit of FIG. 1, and FIG. 6 is a circuit showing a first modification of FIG. FIG. 7 is a circuit block diagram showing a second modification of FIG. 5, FIG. 8 is an explanatory diagram relating to the size of the coil opening, FIG. 8A is an explanatory diagram of a coil having a large opening, and FIG. FIG. 8B is an explanatory diagram showing magnetic lines of force and magnetic noise passing through the opening of the coil of FIG. 8A, and FIG. 8C is a small opening. 8D is an explanatory diagram showing magnetic lines of force passing through the opening of the coil of FIG. 8C, FIG. 9 is an enlarged explanatory diagram of FIG. 8D, and FIG. 11 is an explanatory diagram when the position adjustment is performed, FIG. 11 is an explanatory diagram when the polarities of the exciting magnet and the motor magnet are the same, and FIG. 12 is a diagram from the coil affected by the magnetic field caused by the motor magnet or water to the magnetic fluid. FIG. 12A is a graph showing the signal strength detected from the coil with respect to the distance from the coil affected by the magnetic field by the motor magnet to the magnetic fluid. 12 (B) is a graph showing the signal intensity detected from the coil with respect to the distance from the coil affected by the magnetic field due to water to the magnetic fluid, and FIG. 13 is provided with a correction magnet for correcting the influence of the magnetic field by the motor magnet. The FIG. 14 is a circuit block diagram for removing noise due to the displacement of the coil, FIG. 15 is a graph showing the signal intensity detected from the coil with respect to the frequency in the circuit block diagram of FIG. FIG. 16 is a schematic explanatory view of a magnetic fluid detection device showing a first modification configured so as not to be affected by the motor magnet, and FIG. 17 is a magnetic diagram showing a second modification configured so as not to be influenced by the motor magnet. 18 is a schematic explanatory diagram of a fluid detection device, FIG. 18 is a schematic explanatory diagram of a magnetic fluid detection device showing a third modified example configured so as not to be affected by a motor magnet, and FIG. 19 is configured so as not to be influenced by a motor magnet. It is a schematic explanatory drawing of the magnetic fluid detection apparatus which shows the 4th modification performed.

  As shown in FIG. 1, the ferrofluid detection device 1 of the first embodiment is used from outside the body, in contact with the body surface, or surgically inserted into a body cavity via a trocar, or surgically operated. The probe 2 is used by incising the body surface and bringing it into contact with the inside of the body, and a control unit 4 connected to the probe 2 via a connection cable 3 and controlling the probe 2.

  The probe 2 has a grip portion on the proximal end side so as to be easily gripped and is formed in a pistol shape that is easy to operate, and detects the magnetic fluid 6 staying in the sentinel lymph node 5 inside the subject. A detection unit 7 provided with excitation means and a magnetic sensor, which will be described later, is built in the tip.

  The control unit 4 includes a display unit 8 formed of an LED (Light Emitting Diode) or an LCD (Liquid Crystal Display) for displaying a result detected by the detection unit 7, and a result detected by the detection unit 7. Is provided on the front panel to notify the operator of the detection result of the magnetic fluid 6.

The probe 2 is covered with a probe exterior member 10 made of a nonmagnetic material. When the probe 2 is used for insertion into a body cavity, the probe exterior member 10 is watertight.
As shown in FIGS. 2 and 3, the probe main body 11 has a slide portion 12 provided on the probe distal end side and a drive portion 13 provided on the probe proximal end side.

  The slide portion 12 is made of a non-magnetic material, and a vibration member 14 that can vibrate in the longitudinal axis direction. A distal end side of the vibration member 14 is coupled to the vibration member 14, and a proximal end side is connected to the drive portion 13. 13 and a connecting portion 15 provided with a crank mechanism or the like for transmitting the vibration transmitted from the vibration member 14 to the vibration member 14. That is, the drive unit 13, the vibration member 14, and the connection unit 15 constitute a vibration unit. The vibrating member 14 is formed longer than the connecting portion 15 in order to separate the detecting portion 7 from the metal portion of the probe main body 11.

Further, the slide portion 12 is provided with guide members 16 for sliding and guiding the vibration member 14 in the longitudinal axis direction at two locations, the distal end side and the proximal end side.
The distal end side guide member 16 a is fixedly disposed on the distal end side of the vibration member 14. On the other hand, the proximal end side guide member 16b is fixedly disposed on the proximal end side of the vibration member 14.

The drive unit 13 includes a motor unit 17, and converts the rotational movement of the motor unit 17 into forward and backward movements to transmit vibration to the connecting unit 15.
The vibration member 14 is slid and guided by the distal end side guide member 16a and the proximal end side guide member 16b, and is vibrated in the longitudinal axis direction by vibration transmitted from the drive unit 13 via the connecting portion 15. It comes to vibrate.

Here, if a ball bearing is used between the vibration member 14 and the guide member 16, the vibration distance is short, and the ball bearing and the vibration member 14 or the drive unit 13 are fixed due to heat generation. There is fear.
In the present embodiment, as described above, the vibration member 14 slides on the guide member 16 and is vibrated, so that the heat is not fixed due to the generation of the heat.
The drive unit 13 may be configured to vibrate the vibration member 14 in the longitudinal axis direction using a vibrator (not shown) instead of the motor unit 17.

The detection unit 7 is provided at the tip of the vibration member 14.
As shown in FIG. 4A, the detecting unit 7 is an exciting magnet formed by a permanent magnet such as a neodymium magnet or a samarium / cobalt magnet as an exciting means for exciting the magnetic fluid 6 staying inside the subject. 21 and a coil 22 which is a magnetic sensor for detecting a distortion (spatial magnetic gradient) of a local magnetic field distribution caused by the magnetic fluid 6 excited by the exciting magnet 21 is provided in the detection unit main body 23. As shown in FIG. 4B, the detection unit 7 may be configured to connect the vibration member 14 directly to the motor unit 17 of the drive unit 13.

  The coil 22 is provided on the distal end side of the detection unit main body 23 and is exposed at the distal end portion of the vibration member 14. The exciting magnet 21 is disposed behind the coil 22.

  The detection unit 7 generates an alternating magnetic field as an excitation magnetic field depending on the vibration frequency by vibrating the excitation magnet 21 in the longitudinal direction along with the vibration of the vibration member 14 in the longitudinal direction. The magnetic fluid 6 staying inside the specimen is detected.

Here, in general, the distortion (spatial magnetic gradient) of the local magnetic field distribution by the magnetic fluid 6 increases in proportion to the intensity of the exciting magnetic field (alternating magnetic field), and the magnetic fluid is easily detected.
However, in a magnetic sensor such as a Hall element or a magnetoresistive element, if an exciting magnet having a surface magnetic flux density of 0.1 T (Tesla) or more is arranged, the sensor output is saturated and a magnetic field change due to the magnetic fluid cannot be detected. Considering the thickness of the exterior, it is considered that the distance between the magnetic fluid and the magnetic sensor is at least 1 mm. In a magnetic sensor such as an excitation magnet having a surface magnetic flux density of 0.1 T (Tesla) and a Hall element or a magnetoresistive element, the magnetic fluid cannot be detected unless the distance between the magnetic fluid and the magnetic sensor is 1 mm or less. Then, it becomes almost impossible to detect. Therefore, although the surface magnetic flux density of the exciting magnet is desired to be 0.1 T (Tesla) or more, a Hall element or a magnetoresistive element cannot be used.

  In the present embodiment, as described above, the coil 22 is used as a magnetic sensor.

Formula 1

ｎ：コイル巻き線本数
Ｈ（ｔ）：磁界
に基づき発生するようになっている。

n: number of coil windings H (t): generated based on magnetic field.

Here, since the relative positional relationship between the exciting magnet 21 and the coil 22 does not change, the coil 22 is only subjected to a static magnetic field, and the electromotive voltage v is 0 from (Equation 1).
However, if the magnetic fluid 6 is in the vicinity of the detection unit 7, the magnetic field distribution of the exciting magnetic field generated by the exciting magnet 21 by the magnetic fluid 6 is locally distorted (spatial magnetic gradient), and the magnetic field applied to the vibrating coil 22. From (Equation 1), a value proportional to the differential value of the magnetic field change is output from the coil as an electromotive voltage v.

  When viewed from the magnetic fluid 6, the exciting magnetic field generated by the exciting magnet 21 is an alternating magnetic field. As the exciting magnet 21 is made larger, the electromotive voltage v becomes larger and the detection sensitivity can be increased. The above-described permanent magnets such as neodymium magnets and samarium / cobalt magnets are small, have a large magnetic force, and are suitable for this apparatus. A neodymium magnet having a length of about 5 mm and a diameter of about 10 mm and a surface magnetic flux density of about 0.5 T (Tesla).

  Thus, in this embodiment, the magnetic fluid 6 is excited by the alternating magnetic field, and the distortion (spatial magnetic gradient) of the local magnetic field distribution caused by the magnetic fluid 6 is detected by the coil 22. Furthermore, in this embodiment, magnetic noise from geomagnetism, electrical equipment, and the like is removed by detecting a vibration frequency component from the output from the coil 22 as will be described later.

  The detection unit 7 is provided with a preamplifier unit 24 including a preamplifier 24A for amplifying the output from the coil 22. That is, the detection unit 7 is configured to vibrate the preamplifier unit 24 together with the excitation magnet 21 and the coil 22 in the longitudinal axis direction along with the vibration of the vibration member 14 in the longitudinal axis direction.

  As a result, in this embodiment, the lead wire between the coil 22 and the preamplifier section 24 does not vibrate, so there is no influence of contact resistance change or the like. Although the lead wire between the preamplifier unit 24 and the line driver 26 vibrates, the weak output of the coil 22 is amplified by the preamplifier unit 24. Therefore, even if the signal changes due to a contact resistance change or the like, it is amplified. There is no effect because it is small compared to the signal strength later.

The detection unit 7 is configured by hardening the coil 22, the excitation magnet 21, and the preamplifier unit 24 with resin in the detection unit main body 23.
Further, a line driver 26 for transmitting the output from the detection unit 7 to the control unit 4 is separately attached to the slide unit 12 in the vicinity of the vibration member 14 and is fixedly arranged. . That is, the line driver 26 does not vibrate. This prevents the vibration member 14 from becoming heavy by providing a relatively heavy line driver 26 on the vibration member 14.

An output from the line driver 26 is transmitted to the control unit 4, and signal processing is performed by the control unit 4.
As shown in FIG. 5, the control unit 4 receives a line receiver 31 that receives the output from the line driver 26, and a low-pass filter that removes a harmonic component of the output received by the line receiver 31 and extracts an amplitude component ( LPF) 32, an amplifier 33 for amplifying the signal from the LPF 32, an A / D converter 34 for A / D converting the signal from the amplifier 33, and a digital signal converted by the A / D converter 34 And a digital signal processing circuit 35 formed by, for example, a DSP (Digital Signal Processor) for driving the display unit and the speaker by performing signal processing.

  The control unit 4 includes a motor control circuit 36 that controls and drives the motor unit 17 of the drive unit 13. The motor control circuit 36 outputs a motor drive signal to drive the motor unit 17 and receives a servo signal from the motor unit 17 to perform feedback control so as to stabilize the rotational speed of the motor. It has become. The motor control circuit 36 outputs a pulse signal synchronized with the rotation signal of the motor unit 17 to the digital signal processing circuit 35.

  The digital signal processing circuit 35 demodulates the output signal from the coil 22 (digital signal from the A / D converter 34) based on the pulse signal synchronized with the motor rotation from the motor control circuit 36, The amplitude of the vibration frequency component is detected, and the display unit 8 and the speaker 9 are driven according to the detected signal intensity.

  As a demodulation method, the pulse signal synchronized with the motor rotation and the output signal from the coil 22 (digital signal from the A / D converter 34) are digitally multiplied, or the output signal from the coil 22 (A / D) There is a method of performing a fast Fourier transform (FFT) on a digital signal from the D converter 34 and obtaining a frequency component of a vibration frequency obtained from a pulse signal synchronized with motor rotation. When the rotational speed of the motor is stable and a phase component is not required, a pulse signal synchronized with the motor rotation is not required, and the output signal from the coil 22 (A / D converter) is set with a constant vibration frequency. The digital signal from only 34).

In this case, the digital signal processing circuit 35 displays the display brightness of the LED of the display unit 8 according to the detected signal intensity, the display speed of the indicator formed by the LED or the like, or the numerical display or indicator of the LCD. The display etc. are changed.
The digital signal processing circuit 35 changes the volume, frequency or pulse train period of the speaker 9 according to the detected signal intensity.

The configuration of the control unit 4 shown in FIG. 5 is configured to perform digital signal processing, but may be configured to perform analog signal processing as shown in FIG.
As shown in FIG. 6, the control unit 4 </ b> B includes the line receiver 31, a multiplier 37 that multiplies the output from the line receiver 31 by the pulse signal from the motor control circuit 36, and the output from the multiplier 37. An LPF 32b that removes harmonic components and extracts an amplitude component, a DC amplifier 33b that amplifies an analog signal from the LPF 32b, and the digital signal processing circuit 35 according to the analog signal (voltage) intensity from the DC amplifier 33b Similarly, a voltage controlled oscillator (VCO) 38 that drives the display unit 8 and the speaker 9 is provided.

When the magnetic fluid detection device 1 is configured in combination with an endoscope device, the control unit displays the detection result of the magnetic fluid 6 on a monitor on which an endoscopic image is displayed as shown in FIG. You may comprise.
As shown in FIG. 7, the control unit 4C has a synthesis circuit 41 that synthesizes the detection result with the endoscope image signal output from the endoscope apparatus 40, and monitors the synthesized image signal from the synthesis circuit 41. The detection result of the magnetic fluid 6 is displayed together with the endoscopic image on the display screen of the monitor.

In the present embodiment, as described above, the coil 22 is used as a magnetic sensor.
When the opening 22a of the coil 22 is large as shown in FIG. 8A and FIG. 8B, the range of detecting magnetic noise from an electrical device other than the magnetic lines of force due to the magnetic fluid 6 increases. Magnetic lines of force due to the magnetic fluid 6 are buried in the magnetic noise, and the detection sensitivity is reduced. In general, the size of a lymph node is about 1 cm in the case of a human.

  For this reason, in this embodiment, as shown in FIGS. 8C and 8D, the opening 22a of the coil 22 is formed to be 1 cm or less so as to be smaller than the lymph node. As a result, in this embodiment, as shown in FIG. 9, the range in which the coil 22 detects magnetic noise from an electric device or the like can be reduced as much as possible, and only the magnetic lines of force due to the magnetic fluid 6 can be detected. ing.

  In the present embodiment, the detection unit 7 is vibrated by about 1 to 2 mm in the longitudinal axis direction by vibrating the vibrating member 14 in the longitudinal axis direction. For this reason, a space of about 1 to 2 mm for the detection unit 7 to vibrate is required between the detection unit 7 and the probe exterior member 10 (see FIG. 10B). On the other hand, the thickness of the probe exterior member 10 is, for example, about 0.5 to 1 mm.

  The range in which the magnetic fluid can be detected is at most about 5 mm from the coil 22. In order to increase the detection range as much as possible, in the present embodiment, the exterior is configured by separating the distal end cover 50 and the probe exterior member 10 so that the distance between the distal end cover 50 and the detection unit main body 23 can be finely adjusted. is doing.

More specifically, as shown in FIG. 10A, the tip cover 50 and the probe exterior member 10 are assembled via an adjustment member 43. The adjustment member 43 and the probe exterior member 10 are attached by a screw portion 51 having a minute pitch. The adjustment member 43 is fixed to the probe exterior member 10 at a position where the end surface slightly protrudes from the position of the surface of the detection unit main body 23.
Then, by covering and fixing the tip cover 50 on the adjustment member 43, the distance between the tip cover 50 and the detection unit main body 23 is minimized, and the detection range of the magnetic fluid 6 can be maximized. .

  10B, the front end cover 50 is slidably attached to the exterior member 10, and the front end cover 50 is fixed when it is pulled out a little from where it hits the detection unit main body 23. The method of FIG. 10B is simpler than the method of FIG.

  10 (c) and 10 (d), the tip cover 50 is attached to the detection unit main body 23 via a minute pitch screw part 51. In consideration of water tightness, an O-ring 44 is attached to the tip cover 50. Similarly to FIG. 10B, the tip cover 50 is fixed with an adhesive 45 when it is pulled out a little from where it hits the detector main body 23.

The magnetic fluid detection device 1 configured as described above is used to identify the sentinel lymph node 5 by detecting the magnetic fluid 6 staying in the sentinel lymph node 5 in the subject.
First, the operator inserts a puncture needle (not shown) into the lower layer of the lesioned part of the subject and locally injects the magnetic fluid 6 near the lesioned part. Then, the magnetic fluid 6 injected into the lesioned part moves from the injection site to the lymphatic vessel, reaches the sentinel lymph node 5 after 5 to 15 minutes, and stays in the sentinel lymph node 5.

  Then, the surgeon uses the probe 2 of the magnetic fluid detection device 1 by being surgically inserted into a body cavity through a trocar (not shown), or used from the outside of the body surface. The surgeon detects the magnetic fluid 6 staying in the sentinel lymph node 5 while moving the tip of the probe 2 relative to the vicinity of the lesioned part of the patient.

  At this time, in the probe 2, the motor unit 17 of the driving unit 13 is controlled and driven by the control of the motor control circuit 36 of the control unit 4. Vibration is transmitted to the connecting portion 15.

  The probe 2 is slid-guided by the guide members 16a and 16b and vibrated in the longitudinal axis direction by the vibration transmitted from the driving unit 13 through the connecting portion 15, The detection unit 7 is vibrated in the longitudinal axis direction. Then, the probe 2 generates an alternating magnetic field depending on the vibration frequency when the exciting magnet 21 of the detection unit 7 is vibrated in the longitudinal axis direction.

  Here, when the magnetic fluid 6 exists in the vicinity of the lesioned part of the patient, the alternating magnetic field generated by the exciting magnet 21 excites the magnetic fluid 6 through the space near the probe. Then, the alternating magnetic field is sucked or bounced in the vicinity of the magnetic fluid 6 to cause local distortion in the magnetic field distribution, thereby changing the spatial gradient (magnetic flux density) of the magnetic field distribution. The local magnetic field distribution distortion (change in magnetic flux density) due to the magnetic fluid 6 is detected by the coil 22.

  Here, as described above, the coil 22 is not affected by the excitation magnetic field (an alternating magnetic field when viewed from the magnetic fluid 6, and a static magnetic field when viewed from the coil 22), and the local magnetic field distribution distortion (spatial magnetic field gradient) caused by the magnetic fluid 6 is not affected. ) Can be detected. The output from the coil 22 is amplified by the preamplifier 24A and transmitted to the control unit 4 via the line driver 26.

  Here, the detection unit 7, together with the excitation magnet 21 and the coil 22, is vibrated in the longitudinal direction along with the vibration of the vibration member 14 in the longitudinal direction, as described above. In addition, since the lead wire between the coil 22 and the preamplifier section 24 does not vibrate, there is no influence such as a change in contact resistance. Although the lead wire between the preamplifier unit 24 and the line driver 26 vibrates, the weak output of the coil 22 is amplified by the preamplifier unit 24. Therefore, even if the signal changes due to a contact resistance change or the like, it is amplified. There is no effect because it is small compared to the signal strength later.

Then, the control unit 4 removes the harmonic component from the output received by the line receiver 31 by the LPF 32 and extracts the amplitude component, amplifies the extracted amplitude component by the amplifier 33, and A / D by the A / D converter 34. Convert.
The digital signal processing circuit 35 demodulates the output signal from the coil 22 (digital signal from the A / D converter 34) based on the pulse signal synchronized with the motor rotation from the motor control circuit 36, The amplitude of the vibration frequency component is detected, and the display unit 8 and the speaker 9 are driven according to the detected signal intensity.

  Demodulation is performed by digitally multiplying the pulse signal synchronized with the motor rotation and the output signal from the coil 22 (digital signal from the A / D converter 34), or the output signal from the coil 22 (A / D converter). 34) is subjected to fast Fourier transform, and the frequency component of the vibration frequency obtained from the pulse signal synchronized with the motor rotation is obtained. Here, when the rotational speed of the motor is stable and no further phase component is required, a pulse signal synchronized with the motor rotation is not required, the vibration frequency is constant, and the output signal (A / Digital converter (D signal from D converter 34) only.

  The display unit 8 displays the distortion (spatial magnetic gradient) of the local magnetic field distribution with an indicator or a number. In this case, when the probe tip approaches the magnetic fluid 6, the indicator 8 gradually increases the indicator swing or number, and when the probe tip moves away from the magnetic fluid 6, the indicator swing or number gradually decreases. is doing.

  The speaker 9 generates a sound corresponding to the distortion of the local magnetic field distribution (spatial magnetic gradient). In this case, the speaker 9 generates a sound so that the sound gradually increases when the probe tip approaches the magnetic fluid 6, and the sound gradually decreases when the probe tip moves away from the magnetic fluid 6. Alternatively, the speaker 9 generates sound such that the sound frequency changes in proportion to the distance between the probe 2 and the magnetic fluid 6.

  Thus, the magnetic fluid detection device 1 of the first embodiment can accurately detect the position of the magnetic fluid 6 staying in the sentinel lymph node 5 with good operability and identify the position of the sentinel lymph node 5. Can do.

  Specific examples of the magnetic fluid 6 include ferridex (generic name: filmoxides), MnZn ferrite, and Fe304 magnetite. When these particle sizes are small and stay in the lymph nodes, the concentration becomes thin, so that the force for distorting magnetism becomes weak and the relative permeability is considered to be about 1.0001.

  Therefore, the output signal of the coil 22 is amplified with a large electrical gain. Therefore, the coil 22 is affected by the magnet used in the motor unit 17 for vibration of the detection unit main body 23 located farther than the excitation magnet 21.

As shown in FIG. 11, when the apparatus is assembled so that the magnetic poles of the excitation magnet 21 and the motor magnet 60 are in the same direction, when the coil 22 and the excitation magnet 21 approach the magnetic fluid 6, Thus, since the magnetic field is distorted, the magnetic field applied to the coil 22 is increased.
At this time, since the coil 22 moves away from the motor magnet 60, the magnetic field from the motor magnet 60 becomes small. In other words, the influence of the motor magnet 60 and the magnetic fluid 6 (the magnetic field generated by the motor magnet 60 and the magnetic fluid 6) cancels each other.

In this case, the output signal intensity of the coil 22 is as shown by the dotted line in FIG.
When the magnetic fluid 6 is far from the probe 2 (exists), the magnetic fluid 6 is not affected, and only the magnetic field of the motor magnet 60 is output (position A in FIG. 12A).

On the other hand, when the magnetic fluid 6 is at an appropriate distance from the probe 2, the influence of the magnetic fluid 6 is equal to the influence of the motor magnet 60 (the magnetic field generated by the magnetic fluid 6), and the output signal intensity of the coil 22 approaches zero. (Position B in FIG. 12A).
When the magnetic fluid 6 is near (exists) from the probe 2, the influence of the magnetic fluid 6 is larger than the magnetic pole of the motor magnet 60, and the output signal intensity of the coil 22 is also large (in FIG. 12A, C position).

In this case, the output signal strength of the coil 22 is smaller between ed and d than when the magnetic fluid 6 is not present (does not exist), and the presence or absence of the magnetic fluid cannot be determined. A substantially measurable range is up to position e in FIG.
When the magnetic poles of the exciting magnet 21 and the motor magnet 60 are opposite to each other, when the coil 22 and the exciting magnet 21 approach the magnetic fluid 6, the magnetic field applied to the coil 22 increases.

  At this time, the magnetic field from the motor magnet 60 becomes small. However, since the polarities of the excitation magnet 21 and the motor magnet 60 are opposite, the magnetic fields generated from these are in the direction of strengthening each other. Therefore, the output signal intensity from the coil 22 is as shown by the solid line in FIG.

In this case, since the output signal intensity of the coil 22 is not smaller than when there is no magnetic fluid (does not exist), it can be measured up to the position d.
By assembling the apparatus so that the magnetic poles of the exciting magnet 21 and the motor magnet 60 face in opposite directions, the detection distance of the magnetic fluid can be maximized.
Further, as shown in FIG. 13, the correction magnet 61 may be arranged in a direction that cancels the magnetic field of the motor magnet 60.

In addition, when the probe 2 is used in a living body, it is affected by water contained in the living body. The relative permeability of water is about 0.999991. The difference from air is 0.00001, which is 1/5 to 1/10 of the magnetic fluid. When the concentration of the magnetic fluid is low, the value is substantially close to air and cannot be distinguished.
In this case, when the magnetic force of the correction magnet 61 is increased, even when the probe 2 is in the air, the coil 22 exhibits a large output signal strength as shown in FIG. .

  When the magnetic poles of the correction magnet 61 and the excitation magnet 21 are arranged so as to be opposite to each other, when the probe 2 approaches the magnetic fluid, the magnetic field applied to the coil 22 increases and the magnetic field from the correction magnet 61 decreases. Since the magnetic poles of the correction magnet 61 and the excitation magnet 21 are opposite to each other, the directions are strengthened. Therefore, the output signal intensity of the coil 22 is as shown by the solid line in FIG.

When the probe 2 approaches water, since the relative permeability of water is smaller than 1, the magnetic field applied to the coil 22 is weakened, and the magnetic field from the correction magnet is also weakened. Since the magnetic poles of the correction magnet 61 and the excitation magnet 21 are opposite to each other, the directions cancel each other. Therefore, the output signal intensity of the coil 22 is as shown by the dotted line in FIG.
By increasing the magnetic force of the correction magnet 61, signal changes caused by water and magnetic fluid can be reversed, and magnetic fluid in the living body can be detected.

If the coil 22 is displaced relative to the exciting magnet 21 due to the vibration in the longitudinal axis direction, the detection unit 7 picks up noise due to the displacement.
Therefore, in order to remove noise due to the positional deviation of the coil 22, a configuration as shown in FIG.

  As shown in FIG. 14, the detection unit 7 winds a correction coil 62 around the exciting magnet 21 to detect the positional deviation of the coil 22, and supplies an AC current from the AC power source 63 to the correction coil 62. It is configured as follows.

The AC magnetic field f1 generated by the correction coil 62 is a weak magnetic field that does not affect the magnetic fluid 6 but affects only the coil 22.
When the detection unit 7 is vibrated in the longitudinal axis direction, the output from the coil 22 is caused by the positional deviation of the coil 22 in addition to the distortion of the local magnetic field distribution (spatial magnetic gradient) caused by the magnetic fluid 6. Noise is superimposed.

  That is, as shown in FIG. 15, the signal intensity in the vicinity of the vibration frequency f 0 detected by the coil 22 is due to the positional deviation of the coil 22 in addition to the distortion of the local magnetic field distribution (spatial magnetic gradient) caused by the magnetic fluid 6. Noise will be superimposed. Noise due to the positional deviation of the coil 22 is also superimposed on the AC magnetic field f1 of the correction magnet 61. The influence of the magnetic fluid 6 is not superimposed on the alternating magnetic field f1.

Therefore, by subtracting f1 multiplied by a predetermined coefficient from the signal intensity in the vicinity of the vibration frequency f0, it is possible to remove noise due to the positional deviation of the coil 22.
Therefore, the control unit 4 can remove the noise due to the positional deviation of the coil 22 by performing the subtraction process on the output from the coil 22.

Further, the magnetic fluid detection device may be configured as shown in FIGS. 16 to 19 so as not to be affected by the motor magnet 60.
As shown in FIG. 16, the magnetic fluid detection device 1 </ b> B is configured such that the motor unit 17 is separated from the probe side by a flexible shaft 64. Couplers 65 are used for the connection between the connecting portion 15 and the flexible shaft 64 and for the connection between the flexible shaft 64 and the motor portion 17.

As a result, the magnetic fluid detection device 1B transmits the rotational motion of the motor unit 17 from the flexible shaft 64 via the coupler 65, and converts the transmitted rotational motion of the motor unit 17 into forward and backward movement. Vibration is transmitted to the connecting portion 15.
Therefore, since the magnetic fluid detection device 1B separates the motor unit 17 from the probe side, the detection unit 7 is not affected by the motor magnet 60.

As shown in FIG. 17, in the magnetic fluid detection device 1C, the connecting portion 15 has a hydraulic drive mechanism 66, and the motor portion 17 is separated from the probe side by the hydraulic drive mechanism 66. .
In the hydraulic drive mechanism 66, cylinders 66a are arranged on the probe side and the motor part side, respectively, and the rotational movement of the motor part 17 is converted into advancing and retracting to advance and retract the oil 66b, thereby transmitting vibrations. It has become.

As a result, the magnetic fluid detection device 1 </ b> C transmits vibration to the vibration member 14 by the hydraulic drive mechanism 66 of the connecting portion 15.
Accordingly, in the magnetic fluid detection device 1 </ b> C, the motor unit 17 is separated from the probe side, so that the detection unit 7 is not affected by the motor magnet 60.

As shown in FIG. 18, the magnetic fluid detection device 1D is provided with an air motor 67 on the probe side, and an air compressor 68 that drives the air motor 67 is separated from the probe side.
Then, the magnetic fluid detection device 1D supplies and discharges air from the air compressor 68 through the air tube 68a to rotate the air motor 67, and converts this rotational motion into forward and backward movement to vibrate the connecting portion 15. To communicate.
Thus, the magnetic fluid detection device 1D is provided with the air motor 67 having no magnet on the probe side, so that the detection unit 7 is not affected by the motor magnet 60.

Further, as shown in FIG. 19, the magnetic fluid detection device E is configured by using an ultrasonic motor or an electrostatic actuator 69 that does not have a magnet.
The magnetic fluid detection device E supplies drive current from the control unit 4 to drive and control the ultrasonic motor or electrostatic actuator 69 to transmit vibration to the vibration member 14.
Thereby, since the magnetic fluid detection apparatus E is provided with the ultrasonic motor or the electrostatic actuator 69 which does not have a magnet, the detection part 7 is not influenced by the motor magnet 60.

  FIGS. 20 to 26 relate to a second embodiment of the present invention, FIG. 20 is an explanatory view showing a magnetic fluid detection device of the second embodiment, FIG. 21 is an explanatory view of the drive unit of FIG. 20A is a schematic explanatory diagram of the drive unit of FIG. 20, FIG. 21B is an external view showing the eccentric cam of FIG. 21A, and FIG. 22 is a first modified example configured to increase the detection speed. 23 is a schematic diagram of the probe shown in FIG. 23, FIG. 23 is a schematic diagram of a drive unit showing a second modified example configured to increase the detection speed, and FIG. 24 is an explanatory diagram showing a modified example of the eccentric cam of FIG. 24A is an external view showing a modified example of the eccentric cam of FIG. 22, FIG. 24B is a front view of FIG. 24A, and FIG. 25 is a graph showing signal processing in the configuration of FIGS. FIG. 25A is a graph and diagram showing the position of the vibrating member with respect to time in the configuration of FIGS. 5 (B) is a graph showing an output signal obtained from the coil with respect to time at the position of the vibrating member in FIG. 25 (A), and FIG. 25 (C) shows the result of signal processing of the output signal in FIG. 25 (B). FIG. 26 is a graph showing an output signal obtained from a coil with respect to frequency in another signal processing.

  In the first embodiment, the probe 2 and the control unit 4 are configured separately, but the second embodiment is configured by incorporating a control unit in the probe. Since the other configuration is the same as that of the first embodiment, the description thereof will be omitted, and the same components will be described with the same reference numerals.

That is, as shown in FIG. 20, the magnetic fluid detection device 1F of the second embodiment is configured by providing a probe 2F with a built-in control unit 4.
The probe 2F includes a control board 71 on which a control circuit is mounted as a control unit behind the drive unit 13F, and a battery 72 for supplying power to the rear of the control board 71. The control board 71 is provided with an LED 73 as a display unit connected to the control board 71. The battery 72 may be configured to be charged by an electromotive force from the charging coil 72A.

The probe 2F has the probe exterior member 10F formed transparently, and the light emission state of the LED 73 can be seen through the probe exterior member 10F. The drive unit 13F is configured by providing a motor unit 17.
More specifically, as shown in FIGS. 21A and 21B, the drive unit 13F includes a motor unit 17 and an eccentric cam 74 provided on the output shaft 17a of the motor unit 17. Configured.

  The eccentric cam 74 is connected to a connecting portion 15, and the vibration member 14 is connected to the distal end side of the connecting portion 15 by a spring 75. When the spring 75 is pressed toward the distal end side of the connecting portion 15, the spring 75 receives a biasing force by the spring stopper member 75a.

  The probe 2F is controlled by the control circuit of the control board 71, and the motor portion 17 of the drive portion 13 rotates against the urging force of the spring 75, and this rotational motion is converted into the eccentric cam. It is converted into forward and backward movement by 74 and transmitted to the connecting portion 15 to vibrate the vibration member 14 in the longitudinal axis direction.

  Therefore, in addition to obtaining the same effect as the first embodiment, the magnetic fluid detection device 1F of the second embodiment is composed of only the probe 2F, so that it can be miniaturized and has good operability.

Since the coil 22 detects a change in magnetic flux across the opening 22a (change in magnetic flux density), the output (electromotive voltage) signal increases as the time change increases according to Faraday's law of electromagnetic induction. Become.
Therefore, the detection speed is increased as shown in FIGS.

  As shown in FIG. 22, the drive unit 13 </ b> G is configured by providing a stepped cam 76 instead of the eccentric cam 74. Further, as shown in FIG. 23, the drive unit 13 </ b> H is configured by providing an elliptical cam 77 instead of the stepped cam 76. The stepped cam 76 is provided with a stepped portion on the outer peripheral portion, but a stepped portion 76a may be provided on the end face as shown in FIGS. 24 (A) and 24 (B).

The coil 22 causes the connecting member 15 to retreat abruptly (instantaneously) by the stepped cam 76 of the driving part 13G or the elliptical cam 77 of the driving part 13H to cause the vibration member 14 to abruptly (instantaneously). By retracting to, a very large output (electromotive voltage) signal can be obtained.
At this time, the vibrating member 14 moves forward and backward as shown in FIG. 25A, and the output signal of the coil 22 is obtained as shown in FIG. ing.

  The control circuit provided on the control board 71 performs signal processing as described below on the output signal obtained from the coil 22.

  That is, the control circuit generates an average value AveS1, AveS2, AveS3,... Of the portion where the vibration member 14 retreats suddenly (instantaneously) with respect to the output signal shown in FIG. 14 calculates average values AveN1, AveN2, AveN3,.

The average values AveS1, AveS2, AveS3,... Of the portion where the vibrating member 14 retreats suddenly (instantaneously) is a zone where the magnetic fluid 6 is detected and the speed of the vibrating member 14 is high.
On the other hand, the average values AveN1, AveN2, AveN3,... Immediately after the vibration member 14 moves backward are farthest from the magnetic fluid 6 and are not affected by the magnetic fluid 6, and the speed of the vibration member 14 is slow. It is a noise component.

  Accordingly, the average values AveN1, AveN2, AveN3,. By subtracting, the noise component can be removed.

  Furthermore, by setting the measurement period to be averaged to an integral multiple of one cycle of the commercial power supply, the commercial power supply noise is averaged over one cycle or an integral multiple thereof, and the value is almost zero. Therefore, the influence of commercial power supply noise can be almost eliminated.

As a result of the signal processing, a signal as shown in FIG. 25C is obtained.
Here, SO1 is a value obtained by subtracting AveN1 from AveS1, SO2 is a value obtained by subtracting AveN2 from AveS2, and SO3 is a value obtained by subtracting AveN3 from AveS3.

  Then, when the SO1 is obtained, the control circuit holds the SO1 until the next SO2 is obtained. When the next SO2 is obtained, the control circuit holds the SO2 until the next SO3 is obtained to obtain the presence / absence signal of the magnetic fluid 6. Thereby, the magnetic fluid detection apparatus F can detect the magnetic fluid 6 with higher accuracy.

  Further, as shown in FIG. 26, the control circuit takes a harmonic component such as 2f0 with respect to the fundamental frequency f0 of the vibration frequency, so that the rotation noise of the motor unit 17 is easily superimposed on the motor from the fundamental frequency f0. The rotation noise of the unit 17 can be removed.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[Appendix]
(Additional item 1)
A magnetic fluid detection device for detecting magnetic fluid staying inside a subject,
Exciting means for generating an exciting magnetic field for exciting the magnetic fluid;
A coil for detecting distortion of a local magnetic field distribution caused by the magnetic fluid excited by an excitation magnetic field of the excitation means;
A preamplifier for amplifying the output from the coil;
A magnetic fluid detection device comprising: the excitation means, the coil, and the preamplifier integrally vibrated.

(Appendix 2)
The excitation means, the vibration means for integrally vibrating the coil and the preamplifier, and the vibration of the vibration means are controlled, and the vibration from the output of the coil amplified by the preamplifier is controlled based on the operating state of the vibration means. The magnetic fluid detection device according to item 1, further comprising a control unit that detects a frequency component and notifies a signal intensity according to the detection result.

(Appendix 3)
The vibration means includes a non-magnetic vibration member that can vibrate by providing the excitation means, the coil, and the preamplifier at a tip portion, and a drive unit that vibrates the vibration member,
The control unit drives the driving unit to vibrate the vibration member, and detects a vibration frequency component from the output of the coil based on an operating state of the driving unit. Magnetic fluid detection device.

(Appendix 4)
Item 2. The magnetic fluid detection device according to item 1, wherein the opening of the coil is formed smaller than the lymph node of the subject.

(Appendix 5)
The excitation means is an excitation magnet, and a correction coil is wound around the excitation magnet to generate an alternating magnetic field that acts only on the coil, thereby removing noise caused by the displacement of the coil due to the vibration. Item 3. The magnetic fluid detection device according to Item 2.

(Appendix 6)
The magnetic fluid detection device according to item 2 or 3, wherein the excitation means is a permanent magnet having a surface magnetic flux density of 0.1 T (Tesla) or more.

(Appendix 7)
4. The magnetic fluid detection device according to item 2 or 3, wherein the exciting means is a neodymium magnet or a samarium / cobalt magnet.

(Appendix 8)
The magnetic fluid detection device according to claim 3, wherein the drive unit includes a motor unit, and the rotational movement of the motor unit is converted into forward and backward movement to vibrate the vibration member.

(Appendix 9)
The drive unit includes an air motor and an air compressor that drives and controls the air motor,
The magnetic fluid detection device according to claim 3, wherein the air compressor is separated from the excitation means, the coil, and the preamplifier.

(Appendix 10)
The magnetic fluid detection device according to item 3, wherein the driving unit is an ultrasonic motor or an electrostatic actuator.

(Appendix 11)
The vibrating member is biased by a spring;
The magnetic fluid detection device according to claim 3, wherein the driving unit includes a cam that presses the vibration member against an urging force of the spring.

(Appendix 12)
9. The magnetic fluid detection device according to appendix 8, wherein a magnetic field removing means for removing the influence of the magnetic field by the motor magnet provided in the motor unit is provided.

(Appendix 13)
9. The magnetic fluid detection device according to claim 8, wherein the drive unit separates the motor unit from the excitation unit, the coil, and the preamplifier using a flexible shaft.

(Appendix 14)
9. The magnetic fluid detection device according to appendix 8, wherein the drive unit separates the motor unit from the excitation means, the coil, and the preamplifier using a hydraulic drive mechanism.

(Appendix 15)
The cam has a stepped cam or an elliptical cam for momentarily retracting the vibration member,
The control unit calculates an average value of a portion where the vibrating member retreats instantaneously with respect to the vibration frequency component detected from the coil, and calculates an average value immediately after the vibrating member retreats. The magnetic fluid detection device according to appendix 11, wherein a noise removal process for subtracting a value to remove a noise component is performed.

(Appendix 16)
When the relative permeability of the magnetic fluid is smaller than 1, the magnetic field removing means has the same polarity as the motor magnet and the exciting means, and when the relative permeability of the magnetic fluid is larger than 1, the motor magnet The magnetic fluid detection device according to appendix 12, wherein polarities of the excitation means and the excitation means are different.

(Appendix 17)
Item 13. The magnetic fluid detection device according to Item 12, wherein the magnetic field removing means includes a correction magnet for canceling out the magnetic field of the motor magnet.

(Appendix 18)
16. The magnetic fluid detection device according to appendix 15, wherein in the noise removal process, the interval for calculating the average value is an integral multiple of a cycle of a commercial power supply frequency.

(Appendix 19)
A magnetic fluid detection device for detecting magnetic fluid staying inside a subject,
Excitation means for generating an excitation magnetic field for exciting the magnetic fluid, a coil for detecting distortion of the local magnetic field distribution caused by the magnetic fluid excited by the excitation magnetic field of the excitation means, and a preamplifier for amplifying the output from the coil And a probe having vibration means for vibrating the excitation means, the coil and the preamplifier integrally,
Controls the vibration of the vibration means of the probe and, based on the operating state of the vibration means, detects the vibration frequency component from the output of the coil amplified by the preamplifier and notifies the signal intensity according to the detection result. A control unit to
A magnetic fluid detection device comprising:

(Appendix 20)
Item 20. The magnetic fluid detection device according to Item 19, wherein the probe is formed in a pistol shape with a grip portion.

(Appendix 21)
A magnetic fluid detection device for detecting magnetic fluid staying inside a subject,
Exciting means for generating an exciting magnetic field for exciting the magnetic fluid;
A coil for detecting distortion of a local magnetic field distribution caused by the magnetic fluid excited by an excitation magnetic field of the excitation means;
A preamplifier for amplifying the output from the coil;
Vibration means for integrally vibrating the excitation means, the coil and the preamplifier;
A control unit that controls the vibration of the vibration unit and detects a vibration frequency component from the output of the coil amplified by the preamplifier based on the operating state of the vibration unit and notifies the signal intensity according to the detection result. When,
A magnetic fluid detection device comprising: a probe comprising:

It is explanatory drawing which shows the magnetic fluid detection apparatus of 1st Example of this invention. It is an external view which shows the probe main body at the time of removing the probe exterior member of FIG. It is the schematic of the probe main body of FIG. It is a schematic explanatory drawing of the magnetic fluid detection apparatus of FIG. It is a circuit block diagram of the control part of FIG. FIG. 6 is a circuit block diagram illustrating a first modification of FIG. 5. FIG. 6 is a circuit block diagram illustrating a second modification of FIG. 5. It is explanatory drawing regarding the magnitude of coil opening. FIG. 9 is an enlarged explanatory diagram of FIG. It is explanatory drawing at the time of performing position adjustment of a front-end | tip cover. It is explanatory drawing when the polarity of an exciting magnet and a motor magnet is made into the same polarity. It is a graph which shows the signal strength detected from the coil with respect to the distance from the coil affected by the magnetic field by a motor magnet or water to magnetic fluid. It is a schematic explanatory drawing of the magnetic fluid detection apparatus provided with the correction magnet for correcting the influence of the magnetic field by a motor magnet. FIG. 5 is a circuit block diagram for removing noise due to coil position shift. It is a graph which shows the signal strength detected from the coil with respect to the frequency in the circuit block diagram of FIG. It is a schematic explanatory drawing of the magnetic fluid detection apparatus which shows the 1st modification comprised so that it might not receive to the influence of a motor magnet. It is a schematic explanatory drawing of the magnetic fluid detection apparatus which shows the 2nd modification comprised so that it might not receive to the influence of a motor magnet. It is a schematic explanatory drawing of the magnetic fluid detection apparatus which shows the 3rd modification comprised so that it might not receive to the influence of a motor magnet. It is a schematic explanatory drawing of the magnetic fluid detection apparatus which shows the 4th modification comprised so that it might not receive to the influence of a motor magnet. It is explanatory drawing which shows the magnetic fluid detection apparatus of 2nd Example. It is explanatory drawing of the drive part of FIG. It is the schematic of the probe which shows the 1st modification comprised so that detection speed might become fast. It is the schematic of the drive part which shows the 2nd modification comprised so that detection speed might become fast. It is explanatory drawing which shows the modification of the eccentric cam of FIG. It is a graph which shows the signal processing in the structure of FIG. 22 thru | or FIG. It is a graph which shows the output signal obtained from the coil with respect to the frequency in other signal processing. It is explanatory drawing which shows the movement of the magnetic fluid at the time of using a magnetic fluid as a tracer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic fluid detection apparatus 2 Probe 4 Control part 5 Sentinel lymph node 6 Magnetic fluid 7 Detection part 8 Display part 9 Speaker 10 Probe exterior member 11 Probe main body 14 Vibration member 15 Connection part 17 Motor part 21 Excitation magnet 22 Coil 23 Detection part main body 24 Preamplifier part 24A Preamplifier 26 Line driver 50 Tip cover 51 Screw part Agent Patent attorney Susumu Ito

Claims (3)

A magnetic fluid detection device for detecting magnetic fluid staying inside a subject,
Exciting means for generating an exciting magnetic field for exciting the magnetic fluid;
A coil for detecting distortion of a local magnetic field distribution caused by the magnetic fluid excited by an excitation magnetic field of the excitation means;
A preamplifier for amplifying the output from the coil;
A magnetic fluid detection device comprising: the excitation means, the coil, and the preamplifier integrally vibrated.   The excitation means, the vibration means for integrally vibrating the coil and the preamplifier, and the vibration of the vibration means are controlled, and the vibration from the output of the coil amplified by the preamplifier is controlled based on the operating state of the vibration means. The magnetic fluid detection device according to claim 1, further comprising: a control unit that detects a frequency component and notifies a signal intensity corresponding to the detection result. The vibration means includes a non-magnetic vibration member that can vibrate by providing the excitation means, the coil, and the preamplifier at a tip portion, and a drive unit that vibrates the vibration member,
The control unit controls and drives the drive unit to vibrate the vibration member, and detects a vibration frequency component from the output of the coil based on an operation state of the drive unit. Magnetic fluid detection device.

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