JP3743385B2 - Magnetocardiograph - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetocardiograph for measuring a magnetic field generated from a heart, and more particularly to a magnetocardiograph capable of measuring a magnetocardiogram quickly without restraining a subject. .
[0002]
[Prior art]
Conventionally, attempts have been made to use a superconducting quantum interference device (SQUID) to measure the distribution of a magnetic field generated from the heart, called a magnetocardiogram, to help diagnose and prevent heart disease.
It is generally called a magnetocardiograph, and it grasps the state of the heart while drawing a magnetocardiogram or maintaining a relative positional relationship with the position of the heart such as magnetic field source estimation.
[0003]
In the conventional magnetocardiograph, the sensor array is positioned from above and the magnetic field distribution is measured with the subject lying in the supine position.
Such a conventional magnetocardiograph is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-253212, and a method for measuring the magnetocardiogram without leaving the chest from both sides is proposed.
[0004]
Japanese Patent Application Laid-Open No. 11-253212 discloses a method of setting a subject at a measurement point at the opposite sensor position by moving a bed, and since it can be measured immediately in a sleeping state, a group examination or the like It is suitable for quick processing applications.
[0005]
[Problems to be solved by the invention]
In the conventional magnetocardiograph disclosed in Japanese Patent Application Laid-Open No. 11-253212, a large gantry and a large magnetic shield room for holding a cryostat (dewar) that houses the sensor in a cooled state at a very low temperature. Need. Usually, the magnetic shield room weighs a few tons, and the price is expensive due to the large amount of mu metal used.
[0006]
Japanese Patent Application Laid-Open No. 11-253212 discloses an example in which a cryostat is made small and flat using a high-temperature superconducting element, and the overall configuration is made compact. However, the subject is positioned efficiently. It is difficult.
Also, the method of sandwiching the subject from above or from above and below is not preferable because it takes time until setting and the subject feels pressure.
[0007]
Moreover, when measuring for a long time, a test subject will be fixed and it cannot measure in a relaxed state.
In addition, when the bed is interposed, the magnetic field source (heart) is separated from the sensor by that amount, and the influence of noise on the measurement signal is increased (S / N deterioration), and the positional relationship between the bed and the sensor is also relative to the vibration. This will cause a general deviation and induce vibration noise.
[0008]
Moreover, in the structure which supports a cryostat (Dewar) using a gantry, the sensor in a gantry and a dewar vibrates by ground vibration. Therefore, there is a problem that the magnetic field in the shield room is cut off and is measured as magnetic noise.
Such problems are caused by the structure in which the subject is sandwiched, the bed is a separate structure from the dewar, and the gantry is used.
[0009]
The present invention has been made in order to solve the above-described problems, and can easily align the subject and the sensor without giving a feeling of pressure to the subject. The purpose is to realize a light and small magnetocardiograph that is difficult to receive.
[0010]
[Means for Solving the Problems]
In claim 1 of the present invention, in the magnetocardiograph for measuring the magnetic field generated from the heart, it has a bed on which the subject is placed and an upward measuring surface on which a plurality of magnetic sensors arranged in a matrix are provided, The dewar holds the magnetic sensor upward and houses a cryogen that cools the magnetic sensor inside, and has a dewar fixed inside the bed so that the measurement surface is close to the subject. It has a flange surface in which an opening for filling the cryogen is formed, and this flange surface is arranged on the same plane as the measurement surface or at a position parallel to the measurement surface at a position higher than the measurement surface. Is a magnetocardiography measuring device characterized by
[0012]
According to a second aspect of the present invention, in the magnetocardiograph according to the first aspect of the present invention, a cylindrical magnetic shield case that shields magnetism that enters inside, and the magnetic shield case is provided from the inside to the outside. A magnetocardiogram measurement comprising: a guide rail; and a moving means that is provided at a lower portion of the bed and slides the bed on the guide rail to move in and out of the magnetic shield housing. Device.
[0013]
According to a third aspect of the present invention, in the magnetocardiograph according to the first aspect, the relative positions with respect to the plurality of magnetic sensors are determined in a matrix on the measurement surface of the dewar. A plurality of pressure sensors arranged on the measurement surface, detecting a pressure distribution on the measurement surface of the subject based on outputs of the plurality of pressure sensors, and based on the detected pressure distribution, the subject and the magnetic sensor, It is a magnetocardiograph characterized by detecting the positional relationship.
[0014]
According to a fourth aspect of the present invention, in the magnetocardiograph according to the third aspect , the pressure sensor comprises an elastic hollow container filled with a gas or a liquid, and detects the pressure in the hollow container. Thus, the magnetocardiograph is characterized in that the pressure distribution is detected.
[0015]
According to a fifth aspect of the present invention, in the magnetocardiograph according to the first aspect, image detecting means for detecting at least one of the feature point and the contour of the subject is provided, and at least one of the detected feature point and the contour is provided. The magnetocardiograph is characterized in that the positional relationship between the subject and the magnetic sensor is detected based on the magnetocardiograph.
[0016]
According to a sixth aspect of the present invention, in the magnetocardiograph according to the first aspect, the bed and the dewar are provided inside, and have an opening for opening the table portion to shield the magnetism entering from the outside. A magnetocardiograph comprising: a magnetic shield container comprising a shield member; and a magnetic shield door comprising the shield member, wherein the magnetic shield door is disposed to shield at least the opening and shield the measurement surface by being moved. is there.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an embodiment of the present invention, and FIG. 2 is a perspective view showing a configuration of a bed integrated with a dewar.
[0019]
1 and 2, 1 is a bed, 2 is a subject, 3 is a table unit, 4 is a pillow unit, 5 is a rotating wheel as a moving means for moving the entire bed 1 on the guide rail, and 6 is a guide rail. , 7 is a support that floats and supports the guide rail on the base.
Then, the subject 2 lies with his head on the pillow part 4 and lies in a state where the chest part or the back part is in contact with the upper surface (table surface) of the table part 3 of the bed 1 (back or prone).
[0020]
Dewar 8 is a magnetic sensor (not shown) for measuring magnetism and a cryogen for cooling the magnetic sensor.
Reference numeral 81 denotes a measurement surface of the dewar 8, and a plurality of magnetic sensors (not shown) are provided in a matrix in the measurement surface 81 (inside the dewar 8).
[0021]
Then, as shown in FIG. 2, the dewar 8 has the measurement surface 81 exposed to the table portion 3 so that the outer side of the measurement surface 81 is close to the chest or back of the subject, or is separated by a very thin table plate. It is fixed inside the bed 1.
[0022]
9 is a pressure sensor that is placed on the measurement surface 81 of the dewar 8, detects a pressure applied by the subject 2 to the table unit 3, 10 is an amplifier that processes a signal output from the magnetic sensor in the dewar 8, and 11 is the subject 2. This is a camera as image detecting means for detecting feature points and contours such as upper and lower ends of the sternum and outputting them as image signals.
[0023]
Reference numeral 12 denotes a support column that supports the camera 11, and 13 denotes an image signal output from the camera 11, a magnetocardiogram signal output from the magnetic sensor, and a pressure output from the pressure sensor 9. A data collection processor for outputting a magnetic diagram and a pressure distribution, 14 is a display for displaying an image by superimposing signals processed by the data collection processor 13, and 15 is a pressure sensor driver for driving a pressure sensor.
[0024]
Reference numeral 16 denotes a circular or square cylindrical magnetic shield casing made of a high permeability material such as permalloy or amorphous magnetic material, 17 a frame for supporting the magnetic shield casing, and 18 an entire magnetic shield casing 16. It is a prop that supports
[0025]
Next, the configuration of the dewar shown in FIGS. 1 and 2 will be described in detail with reference to FIG.
3A and 3B are a top view and a cross-sectional view showing the configuration of the dewar.
In FIG. 3, the dewar 8 is composed of a double container having a vacuum heat insulating layer, and the material of the container is a non-magnetic fiber reinforced plastic such as glass epoxy.
A magnetic sensor (SQUID sensor) is held in the dewar 8 and cryogen such as liquid nitrogen is injected.
[0026]
810 is a vacuum layer, 811 is a cryogen layer for storing a cryogen such as liquid nitrogen, and 812 is a packing provided in an opening for filling the cryogen to block outside air. The surface forms a flange surface 813. ing.
Reference numeral 814 denotes a heat insulating layer made of a material such as foamed polyurethane, and reference numeral 815 denotes an injection exhaust port for injecting the cryogen penetrating the packing 812 or exhausting the evaporated cryogen. Reference numeral 816 denotes an exhaust valve for exhausting the degassing from the gap between the vacuum layers.
[0027]
Reference numeral 81 denotes an upward measuring surface applied to the subject's chest or back surface, and 817 denotes a plurality of magnetic sensors such as a gragiometer and a magnetometer provided in a matrix form inside the measuring surface 81 (inside the cryogen layer 811). A plurality of magnetic sensors 817 are held upward by a sensor holder 818.
Reference numeral 819 denotes a heat transfer material that keeps the inside of the container at a uniform temperature, and 820 denotes a wire that draws the output signal of the magnetic sensor 817 to the outside of the dewar 8 and inputs it to the amplifier 10 shown in FIG.
[0028]
As shown in FIG. 2, the entire dewar 8 is exposed to the table portion 3 of the bed 1 by a fixture (not shown) so that the outside of the measurement surface 81 is close to the chest or back of the subject. Alternatively, it is fixed inside the bed 1 via a very thin table plate (not shown).
[0029]
In FIG. 3, since the flange surface 813 is formed on the same plane as the measurement surface 81, it can be held without leaking the cryogen or speeding up evaporation.
[0030]
In addition, the flange surface 813 is not limited to the same plane as the measurement surface 81, but is disposed at a position higher than the measurement surface 81 and parallel to the measurement surface 81, or an angle between the flange surface 813 and the measurement surface 81 is 90. Even if it is disposed at a position where the angle is not less than 180 degrees and not more than 180 degrees, the cryogen can be retained without leaking or accelerating evaporation.
[0031]
Next, the configuration of the pressure sensor will be described in detail with reference to FIGS.
In FIG. 4, reference numeral 19 denotes a thin mat, and a plurality of pressure sensors 20 are stuck on the mat 19 in a matrix.
And the pressure sensor 20 is comprised with the elastic hollow container with which air or the fluid was filled, and the tube 21 which transmits a pressure to the exterior is connected to each.
[0032]
FIG. 5 is a diagram for explaining the details of the pressure sensor shown in FIG. 4 and its operation mechanism.
In FIG. 5, reference numeral 22 denotes an electric pressure gauge, which detects the pressure in the hollow container constituting the pressure sensor 20 and sends a detection signal to the outside through a lead-out line (not shown).
Reference numeral 23 is an adjustment valve for external control, and 24 is a pressure pump or cylinder for applying pressure to a fluid such as gas or liquid.
The pressure sensor driver 15 shown in FIG. 1 is configured by the pressure gauge 22, the adjustment valve 23, and the pressure pump 24.
[0033]
4 is disposed on the measurement surface 81 of the dewar 8 shown in FIGS. 1 and 2, and the plurality of pressure sensors 20 are arranged on the measurement surface 81. Measure the pressure distribution by the subject.
The mat 19 is preliminarily positioned with respect to the pressure sensor 20 and the magnetic sensor 817, and the internal pressure of the pressure sensor 20 is set to a predetermined pressure by the pressure gauge 22 and the adjustment valve 23 when there is no subject. Adjusted.
[0034]
Next, the operation of the magnetocardiograph shown in FIG. 1 will be described.
First, the subject 2 is laid with the chest or back in contact with the table 3 of the bed 1 (back or prone), and the rotating wheel 5 is slid on the guide rail 6 to place the bed 1 inside the magnetic shield housing 16. Move to.
The magnetic sensor measures the magnetocardiogram of the subject 2 and the amplifier 10 processes the output.
[0035]
In this case, since the bed 1 and the dewar 8 are integrally formed, a large gantry for holding the dewar 8 is not necessary, and the magnetic sensor is not affected by the vibration of the gantry due to the ground vibration or the like, and has a low noise and a magnetocardiogram. In addition, since the large magnetic shield room is not required, the entire system can be made inexpensive.
[0036]
Further, since the subject 2 is not sandwiched from above or from above and below, setting time is not required, and the feeling of pressure applied to the subject 2 can be reduced.
Further, since the magnetic sensor is provided close to the magnetic field source (heart), it is possible to reduce the influence of noise on the measurement signal due to vibration or the like.
[0037]
The pressure sensor 9 detects the pressure distribution that the subject 2 exerts on the table unit 3 and the measurement surface 81, the camera 11 detects the contour and feature points of the subject 2 and outputs them as image signals, and the data collection processor 13 The image signal output from the camera 11, the magnetocardiogram signal output from the magnetic sensor, and the pressure distribution signal output from the pressure sensor 9 are processed.
[0038]
Then, the display 14 is based on the signal processed by the data collection processor 13, for example, as shown in FIG. 6, the subject's contour 25, for example, feature points 26 and 27 such as the upper and lower ends of the sternum, the pressure distribution 28, The magnetocardiogram (the magnetocardiographic spatial intensity distribution diagram) that is not displayed is superimposed and displayed.
[0039]
FIG. 6 is a diagram showing an example of a subject's pressure distribution and body contour displayed on the display.
In FIG. 6, since the body weight concentrates on the subject's scapula and the projections of the buttocks, the contour pressure distribution 28 is displayed as the pressure concentration portion detected by the pressure sensor.
[0040]
Then, by measuring the positions of the scapula and the protrusions of the buttocks and the position of the subject's heart in advance, the actual heart position 29 can be substantially specified from the pressure distribution, and the relative relationship between the pressure sensor and the magnetic sensor can be determined. Since the position is determined in advance, it can be confirmed whether or not the position of the heart is at an appropriate position of the magnetic sensor.
[0041]
Further, in FIG. 6, the contour 25 and feature points 26 and 27 of the subject detected by the camera are displayed.
Then, the actual heart position 29 is substantially specified from the contour 25 and the feature points 26 and 27 detected by the camera by measuring in advance the subject's contour and the relative position between the feature point and the subject's heart position. It is possible to confirm whether the position is at an appropriate position with respect to the magnetic sensor.
[0042]
In this way, by continuously monitoring the pressure distribution, contour, and feature points on the display during magnetocardiogram measurement, the magnetocardiogram can be measured while continuously checking the position of the subject on the table. If the position is correct, the alignment can be corrected efficiently.
[0043]
Moreover, even when measuring for a long time, since it is not necessary to make the test subject excessively restrained, the test subject can be measured in a relaxed state.
[0044]
7 and 8 are diagrams showing the configuration of another embodiment of the present invention.
In addition, the same part as FIG. 1 is attached with the same number, and the description is abbreviate | omitted suitably.
In FIG. 7, reference numeral 30 denotes a magnetic shield container, in which a bed 1 and a dewar 8 are provided.
Reference numeral 31 denotes an opening provided in the magnetic shield container 30 for placing the subject 2 on the bed 1.
[0045]
32 is a magnetic shield door made of a shield member, 33 is a guide rail, 34 is a rotating wheel, and the magnetic shield door 32 is moved on the guide rail 33 by the rotating wheel 34 so that the opening 31 is closed and encapsulated. Let
[0046]
In this case, since the magnetic shield door 32 is moved without moving the bed 1, the movable mechanism can be simplified.
Although it is necessary to increase the rigidity of the movable mechanism, a non-magnetic material and a non-metallic material are required, and design restrictions are large.
However, when the magnetocardiograph is encapsulated as shown in FIG. 7, the movable part of the magnetic shield door 32 does not enter the inside of the magnetic shield space.
[0047]
FIG. 8 is provided with a rotating means 35 for rotating the bed 1 in the standing direction of the subject. In this case, the angle between the flange surface 813 of the dewar 8 and the flange surface 813 and the measurement surface 81 is 90 degrees or more and 180 degrees. It arrange | positions in the position used as follows.
[0048]
In this case, consistency with a magnetic shield container (not shown) is deteriorated, but the configuration is effective for magnetocardiogram measurement under measurement conditions such as standing.
[0049]
【The invention's effect】
As described above, according to the present invention, since the dewar and the bed are integrated, the apparatus can be miniaturized and the space to be shielded can be reduced.
Therefore, not only the cost of the apparatus is reduced, but also the apparatus can be installed in a small room, and the shield container can be made small, so that it is light in weight and can be used for a mobile measuring vehicle or the like.
[0050]
In addition, according to the present invention, since there is no gantry, the rigidity is improved and the influence of vibration of the ground or the like is eliminated, and the signal quality can be improved.
[0051]
In addition, according to the present invention, since the measurement can be performed from the back rather than the structure sandwiched from the upper surface of the chest, the feeling of pressure given to the subject can be reduced, the upper part of the human body is not restrained, and the open feeling can be maintained. Can relax the subject.
[0052]
In addition, according to the present invention, since the pressure concentration part, contour, and feature points of the subject can be detected while wearing clothes, the lead time associated with undressing and the like is unnecessary for the inspection, and it is necessary for the heating and privacy of the examination room. There is no need to pay special attention to consideration. Therefore, it is convenient for mass screening.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a perspective view showing a configuration of a bed integrated with a dewar.
FIG. 3 is a top view and a cross-sectional view showing a configuration of a dewar.
FIG. 4 is a diagram for explaining a configuration of a pressure sensor.
5 is a diagram for explaining the details of the pressure sensor shown in FIG. 4 and its operating mechanism. FIG.
FIG. 6 is a diagram showing an example of a subject's pressure distribution and body contour displayed on the display.
FIG. 7 is a diagram showing the configuration of another embodiment of the present invention.
FIG. 8 is a diagram showing the configuration of another embodiment of the present invention.
[Explanation of symbols]
1 Bed 2 Subject 3 Table 5 Rotating wheel 6 Guide rail 8 Dewar 9 Pressure sensor 11 Camera 13 Data collection processor 16 Magnetic shield housing 30 Magnetic shield container 31 Opening portion 32 Magnetic shield door 35 Rotating means 81 Measuring surface 811 Cold agent layer 813 Flange surface 817 Magnetic sensor

Claims (6)

In a magnetocardiograph that measures the magnetic field generated from the heart,
A bed on which the subject is placed;
It has an upward measuring surface on which a plurality of magnetic sensors arranged in a matrix are provided , holds the magnetic sensor upward, and stores therein a cryogen that cools the magnetic sensor, and the measuring surface is provided to the subject. And a dewar fixed inside the bed so as to be close to each other,
The dewar has a flange surface in which an opening for filling the cryogen is formed, and the flange surface is arranged on the same plane as the measurement surface or at a position parallel to the measurement surface at a position higher than the measurement surface. The magnetocardiograph is characterized by the above. The magnetocardiograph according to claim 1, wherein
A magnetic shield case that shields the magnetism that enters the inside in a cylindrical shape;
A guide rail provided from the inside to the outside of the magnetic shield housing;
A moving means provided at a lower portion of the bed and sliding the bed on the guide rail to enter and exit the magnetic shield housing; and
A magnetocardiography measuring device characterized by comprising: The magnetocardiograph according to claim 1, wherein
Provided with a plurality of pressure sensors arranged in a matrix on the measurement surface of the Dewar, and arranged at predetermined positions relative to the plurality of magnetic sensors,
A pressure distribution on the measurement surface of the subject is detected based on outputs of a plurality of the pressure sensors, and a positional relationship between the subject and the magnetic sensor is detected based on the detected pressure distribution. A magnetocardiograph. The magnetocardiograph according to claim 3, wherein
2. The magnetocardiograph according to claim 1, wherein the pressure sensor is formed of a hollow container that is filled with gas or liquid and has elasticity, and detects the pressure distribution by detecting the pressure in the hollow container. The magnetocardiograph according to claim 1, wherein
An image detecting means for detecting at least one of the feature point and the contour of the subject is provided,
A magnetocardiography measuring apparatus that detects a positional relationship between the subject and the magnetic sensor based on at least one of the detected feature point and outline. The magnetocardiograph according to claim 1, wherein
The bed and the dewar are provided inside, a magnetic shield container made of a shield member that has an opening that opens the table portion and shields magnetism entering from the outside, and
A magnetocardiograph comprising the shield member and provided with a magnetic shield door that closes at least the opening and shields the measurement surface by moving the shield member.

Images