JP2002136494A - Method for measuring magnetic field - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic field measuring method through the use of sheets with high magnetic permeability. SOLUTION: A magnetic field shielding device 40 is the one where a plurality of sheets having high magnetic permeability are arranged by partial superimposition on pluralities of non-magnetic cylindrical members which is arranged by concentrically enclosing a first direction axis to have a hollow part, where the most inner cylindrical member is provided with first and second openings 41 and 42 at both ends in a first direction and with a third opening being put through the cylindrical members in a vertical direction with respect to the first direction axis and also by which a component in the vertical direction concerning the first direction in an extraneous magnetic field is shielded in the internal space of the most inner cylindrical member. A living body is loaded on loading devices in the internal space of the device 40 or the loading devices where the living body is loaded are carried into the internal space. The bottom surface of a cryostat 50 for keeping low temperature in pluralities of SQUID flux meters is arranged to face the front surface of the living body and, then, the component in the vertical direction concerning the first direction in the magnetic field generated from the living body is detected by the SQUID flux meters. Thus, the magnetic field is measured with high performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly sensitive quantum interference device (SQUID: super
The present invention relates to a magnetic field shielding device for measuring using a plurality of magnetometers comprising a conducting quantum interference device, and a magnetic field measuring method and a magnetic field measuring device using the same. In particular, the present invention relates to a magnetic field shielding device for measuring a biomagnetic field generated by a myocardial activity or the like of a living body, and
The present invention relates to a biomagnetic field measurement method and a biomagnetic field measurement device using the same.

[0002]

2. Description of the Related Art A magnetic shield in which a plurality of cylindrical shields having different diameters are sequentially arranged concentrically and a gap is formed between the cylindrical shields has been reported (prior art 1: Japanese Patent Application Laid-open No.
-214166).

In the technique described in the prior art 1, a thickness of 0.1
Using a magnetic shielding material made of tape-shaped permalloy with a thickness of 20 mm to 0.5 cm and a width of 20 cm to 50 cm, the magnetic shielding material is spirally wound around a lightweight plastic cylinder as a core, and the width of the overlapped portion overlapped without gaps Of 5 cm to 10 cm is formed in a cylindrical shape.
The overlap portion has substantially two to five layers, and is spirally wound so that the total thickness is about 0.5 mm to 3 mm. Also, rivets are provided in the overlap portion at intervals of 30 cm in the circumferential direction and are fixed by tightening, and the bonding surface of the overlap portion is in contact with metal.

The prior art 1 describes, as a conventional technique, the production of a shielded room such as a prefabricated room using a large number of permalloy plates, which are Ni-Fe-based alloy materials having high magnetic permeability. There is a problem with this conventional technology that it takes a long time to manufacture a magnetic shield, the number of parts is large, and the magnetic shield becomes very expensive. There is a statement that it is desired to reduce the price of the magnetic shield.

[0005] It has been reported that a light-weight shield room is manufactured by using a magnetic shield sheet in which a soft magnetic amorphous alloy film and a polymer film are bonded together as a magnetic shield material, instead of a permalloy plate ( Prior art 2: JP-A-2000-077890).

[0006]

In the prior art 1 and the prior art 1 in which a shield room is manufactured by combining permalloy plates, there is a problem that an annealing process of permalloy after processing is required, and a problem that a large area is required. However, there is a problem that the weight of the shield room is large and there is a limit to a place where the shield room is installed, and there is a problem that the shield room becomes expensive. In the prior art 2, the weight of the shield room can be reduced and the price can be reduced as compared with the prior art 1 in which a shield room is manufactured by combining permalloy plates, but the problem of requiring a large area is solved. Therefore, a lighter and lower price shielded room was desired.

An object of the present invention is to provide a light-weight, small-sized, high-performance magnetic field shielding device at a low cost by using a high magnetic permeability sheet having a high magnetic permeability, and to reduce a magnetic field generated from an object to be inspected, particularly, a living body. An object of the present invention is to provide a magnetic field measurement method and a magnetic field measurement device for measurement.

[0008]

A representative magnetic field measuring apparatus according to the present invention includes a magnetic field shielding apparatus for shielding a component of an external magnetic field in a direction perpendicular to a first direction, and a magnetic field shielding apparatus for generating a magnetic field generated from an inspection object. A plurality of SQs for detecting components in a direction perpendicular to one direction
A cryostat that holds the UID magnetometer at low temperature, a device that holds the cryostat, a drive detection circuit that drives the SQUID magnetometer, and detects a signal from the SQUID magnetometer, and collects the output of the drive detection circuit to perform arithmetic processing. It comprises an arithmetic processing unit and a display device for displaying the output of the arithmetic processing unit.

The magnetic field shielding device of the present invention is formed by arranging a plurality of non-magnetic cylindrical members having hollow portions so as to concentrically surround the axis in the first direction. On the surface (inner surface and / or outer surface) of each tubular member, a plurality of high permeability sheets having high permeability
They are affixed and arranged so that a part of them is mutually overlapped.

The innermost tubular member has a first opening at one end in a first direction and a second opening at the other end in the first direction. A third opening is formed through the plurality of tubular members in a direction perpendicular to the axis in the first direction. In the space inside the innermost cylindrical member, the component of the external magnetic field in the direction perpendicular to the first direction is shielded. When the test object is a living body, the living body (subject) is mounted in the space inside the cylindrical member arranged at the innermost side with the body axis direction of the test target part substantially parallel to the axis in the first direction. A living body mounted device (bed, chair) is arranged.

[0011] A part of the cryostat is inserted into the third opening, and the bottom surface of the cryostat is disposed in the inner space. By making the diameter of the third opening smaller than the diameter of the bottom surface of the cryostat and inserting the small diameter portion of the cryostat into the third opening, it is not necessary to increase the diameter of the third opening. The magnetic field shielding rate of the extraneous magnetic field can be improved. The third opening is, when the test object is a living body, a chest surface of the living body (subject), or
Facing the back, the bottom surface of the cryostat is disposed in the chest space of the living body or in the inner space facing the back.

The positional relationship between the bottom surface of the cryostat and the surface to be inspected is adjusted by a position adjusting device, and the positional relationship is adjusted in a direction perpendicular to the first direction. The position adjusting device can change the position of the cryostat or the position of the mounting device on which the inspection object is mounted in a second direction perpendicular to the first direction. Further, the position adjusting device may be arranged in a third direction perpendicular to the first and second directions, and in the first direction.
The position of the mounting device can be changed.

Further, the magnetic field shielding device is provided with a fourth opening which penetrates each cylindrical member in a direction perpendicular to the axis of the first direction. The opening 4 is within the field of view of the subject, giving the subject a sense of openness.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, an examination object will be described as a typical example of a living heart. The present invention is not limited to the heart of a living body, and it is needless to say that the present invention can be applied to, for example, inspection of the presence / absence of a magnetic substance and distribution of the magnetic substance included in a general inspection target. Since the configuration of the device of the present invention does not require a large area, it can be used, for example, as an inspection device for dangerous substances including magnetic substances,
It is also applicable to inspection of baggage at ports and the like.

According to the magnetic field shielding apparatus of the present invention, a plurality of high permeability sheets having flexibility and a small thickness including a thin layer of a magnetic material having high permeability composed of amorphous or polycrystalline, or And a plurality of high-permeability sheets using a high-permeability magnetic material composed of an alloy containing Ni. The high magnetic permeability sheet used in the present invention is flexible.

The plurality of high-permeability sheets are arranged such that a part of the high-permeability sheet is overlapped with two to five non-magnetic cylindrical members having a hollow portion. The plurality of tubular members are the first
Are fixed and arranged so as to concentrically surround the axis in the direction of. In the high-permeability sheet, a region where the magnetic material is arranged is formed in a strip shape sandwiched between non-magnetic holding sheets (eg, paper, polymer film, metal film). Overlap on the long sides of adjacent strips,
The long sides of the plurality of strips are arranged substantially in parallel.

The short sides of a plurality of strips of each high magnetic permeability sheet are
The high magnetic permeability sheet is disposed substantially parallel to the axis in the first direction, and the long side of the plurality of strips of each high magnetic permeability sheet is placed on the surface (inner surface and / or outer surface) of each of the plurality of cylindrical members. It is stuck and held so as to surround the axis in the direction of. By arranging a plurality of regions in which the magnetic material having such a strip shape is arranged, the magnetic field shielding rate of an external magnetic field is improved.

The innermost cylindrical member has a first member.
A first opening is provided at one end in the direction
Openings are formed. A third opening is formed to penetrate the plurality of cylindrical members in a direction perpendicular to the axis of the first direction and to insert a cryostat that holds the plurality of SQUID magnetometers at low temperature. In the space inside the innermost cylindrical member, the component of the external magnetic field in the direction perpendicular to the first direction is shielded.

A more preferable shape of the cross section of the plurality of cylindrical members perpendicular to the axis in the first direction is a circle having higher symmetry from the viewpoint of improving the magnetic field shielding rate of an external magnetic field. The circle may be crushed in a direction perpendicular to the axis in the first direction, for example, by about 10% of the diameter of the circle.

A more preferred shape of the innermost cylindrical member having a cross section perpendicular to the axis in the first direction has a diameter of about 5 mm.
It is a circle of 0 cm or more and about 200 cm or less, and does not give a subject a feeling of oppression inserted into the innermost tubular member. In the case of a device dedicated to examining children, the inner diameter of the cylindrical member that is located farther inside should be about 50 cm. The inside diameter of the cylindrical member disposed on the inside may be about 50 cm.

As a plurality of non-magnetic cylindrical members, from the viewpoint of the manufacture and cost of the magnetic field shielding device, the thickness is 0.5 mm to 1 mm.
It is more preferable to use a hollow cylinder made of FRP or aluminum having a diameter of 0.1 mm.

In the space inside the innermost cylindrical member, where the component of the extraneous magnetic field in the direction perpendicular to the first direction is shielded, the subject can comfortably take one of the following three modes. Placed in a state, the body axis direction of the part of the subject whose biomagnetic field is to be detected is substantially parallel to the axis of the first direction, for example, a living body generated from a fetus or the like in the chest or abdomen of the subject. A magnetic field is detected. (1) When the axis in the first direction is substantially horizontal with respect to the floor, the bed on which the subject lies is placed in a substantially horizontal state inside the innermost tubular member. . (2) When the axis in the first direction is substantially perpendicular to the floor, the subject is placed inside the innermost tubular member while sitting on a chair. (3) When the axis of the first direction is inclined at an angle of not less than 20 degrees and not more than 30 degrees with respect to the horizontal plane, the bed on which the subject lies is inclined, or the chair on which the subject sits is tilted. It is arranged inside the innermost tubular member with the backrest angled.

The third opening and / or the fourth opening are formed in any one of the following three modes. (1) A hole is formed in each cylindrical member, and a plurality of cylindrical members are fixed to each other so as to concentrically surround the axis in the first direction and integrated, thereby forming each cylindrical member. The third opening is formed by the hole. In addition to the mode (1), a part of each cylindrical member is configured to be movable, and the third and / or fourth openings are formed by moving a part of each cylindrical member.

That is, a part of each cylindrical member is movable in any one of a first direction, a circumferential direction surrounding the axis of the first direction, and a direction intersecting the first direction. A third and / or fourth opening is formed by movement of a portion of the profile. Specific embodiments will be described below. (2) Each cylindrical member is divided in the first direction into two parts, a first part and a second part. Each of the cylindrical members of the first and second portions is integrally fixed and integrated so as to concentrically surround the axis in the first direction. The first part is the second
Can be separated by moving in the first direction with respect to the portion.

Each cylindrical member of the first portion has a first notch having a semicircular portion opening at an end. Each tubular member of the second portion has a second notch having a semicircular portion opening at the end.

The movement of the first part in the first direction relative to the second part causes the end of the first part and the end of the second part to overlap in the first direction. The third and / or fourth openings are formed by the second cutout portion.

In addition to the first movement of the first part relative to the second part in the first direction, a second movement in a direction crossing the first direction is also possible. The first move, or
An opening is formed in the magnetic field shielding device by the first movement and the second movement. (3) Each cylindrical member is divided into two parts, a first part and a second part, in the circumferential direction surrounding the axis in the first direction. Each of the cylindrical members of the first and second portions is fixed and integrated with each other. The first portion is configured to be movable in a circumferential direction surrounding the second portion.

Each cylindrical member of the first portion has a first notch having a semicircular portion opened on one side substantially parallel to the first direction. Each cylindrical member of the second portion has a second notch having a semicircular portion that opens on one side substantially parallel to the first direction.

The movement of the first part in the circumferential direction surrounding the axis in the first direction with respect to the second part causes the first part and the second part to move in the circumferential direction surrounding the axis in the first direction. Duplicate results,
A third opening is formed by the first and second notches.

The first portion and the second portion overlap each other on two sides substantially parallel to the first direction in a range from about 10 degrees to about 15 degrees in a circumferential direction surrounding the axis in the first direction. . The movement of the first part causes about 90 in the circumferential direction surrounding the axis in the first direction.
Openings in the range of degrees are formed in the magnetic shielding device.

In another configuration of the magnetic field shielding device, as described in the above (2) and (3), each cylindrical member is the first member.
And the second portion are formed so as to be divided into two, and the third opening is formed, but the above-described third opening is not formed. The bottom of the cryostat is inserted through the first opening and the second opening. The fourth opening is formed at a position far from the subject to be inspected by the subject, so that the magnetic field shielding rate of the external magnetic field does not deteriorate.

Hereinafter, the procedure of magnetic field measurement according to the present invention will be described.

First, a part of each cylindrical member of the magnetic field shielding device is moved in any one of a first direction, a circumferential direction surrounding an axis of the first direction, and a direction intersecting the first direction. Thus, an open portion is formed.

The living body is mounted on a living body mounting device (bed, chair) placed in a space inside the magnetic field shielding device through an opening from a direction crossing the axis of the first direction. Alternatively, the living body mounting device on which the living body is mounted is moved along the axis in the first direction, from the direction substantially parallel to the first direction, or from the direction crossing the axis in the first direction, through the opening portion. It is carried into the space inside the shielding device.

Next, a part of each cylindrical member is moved in any one of the first direction, the circumferential direction surrounding the axis in the first direction, and the direction intersecting the first direction, thereby opening the cylindrical member. Close the part. As a result, a third and / or fourth opening is formed, and a part of the cryostat is inserted into the third opening.

The positional relationship between the bottom surface of the cryostat placed in the space inside the magnetic field shielding device and the surface of the living body is
Adjustment is performed in a direction perpendicular to the first direction so that a large magnetic field signal is detected. The components of the magnetic field generated from the living body in the direction perpendicular to the first direction are detected by the plurality of SQUID magnetometers.

According to the present invention, it is possible to provide a light-weight, small-sized, low-cost, high-performance magnetic field shielding device having a high magnetic field shielding ratio of an external magnetic field. A magnetic field measurement method and a magnetic field measurement device for measurement can be provided.

Further, since the magnetic field shielding device of the present invention is lightweight and small, it does not particularly require load resistance at the place where it is installed, and can be installed if it has a small area. In addition, there is no restriction on the place where the magnetic field measuring device is installed.

Here, the time variable is t, and the surface of the living body is (x,
y) The direction perpendicular to the plane and the plane of the living body is defined as the z direction. The positions of the SQUID magnetometers arranged in a two-dimensional grid at equal intervals near the bottom surface inside the cryostat are (x, y),
The magnetic field component (normal component) of the biomagnetic field detected by the SQUID magnetometer is defined as Bz (x, y, t).

In the magnetic field measuring apparatus of the present invention, the tangential components Bx (x, y, t) and By (x, y, t) of the biomagnetic field are respectively measured by the measured normal component Bz (x, y, t). In the x direction 比例 Bz (x, y, t) / ∂x, y The change rate in the ∂Bz (x, y, t) / ∂y is obtained as a value proportional to the change rate. Assuming that the proportionality constant is 1, the tangent component Bx (x, y,
t) and By (x, y, t) are given by (Equation 1) and (Equation 2).

[0041]

Bx (x, y, t) = − (∂Bz (x, y, t) / ∂x) (Equation 1)

[0042]

## EQU2 ## By (x, y, t) =-(∂B (x, y, t) z / ∂y) (Equation 2) Next, the rate of change in the x direction and the rate of change in the y direction are given by 2 A value St (x, y, t) proportional to the square root of the sum of squares is obtained. Assuming that the proportionality constant is 1, the magnetic field waveform St (x, y, t) is given by (Equation 3).

[0043]

## EQU3 ## St (x, y, t) = √ [｛∂Bz (x, y, t) / ∂x｝ 2+ ｛∂Bz (x, y, t) / ∂y｝ 2] (number 3) St (x, y, t) represents the magnetic field source inside the living body as (x, y, t).
y) Give magnetic field intensity information projected on the surface. As t
Taking the peak position of each wave of Q, R, and S, St (x, y,
From the data of t), an isomagnetic field diagram connecting (x, y) points giving the same magnetic field strength by interpolation and extrapolation is obtained.

Next, for each point (x, y), the integrated value I (x, y) of the magnetic field waveform St (x, y, t) in an arbitrary period
Is obtained by (Equation 4), and the integrated value I is obtained by interpolation and extrapolation.
An isointegral diagram connecting points where (x, y) has the same value is obtained.

As the integration range, for example, when the heart is to be measured, the period during which the Q, R, and S waves are generated, Q
The period of the QRS complex (QRS complex) in which the S-wave is generated from the wave,
A period during which the T wave is generated is taken.

[0046]

I (x, y) = ∫ | St (x, y, t) | dt (Equation 4) Further, a time waveform V of a magnetic field intensity obtained by synthesizing magnetic field components in three directions x, y, and z. By calculating (x, y, t) by (Equation 5), a stable magnetic field waveform can be obtained, especially in a case where the movement is severe such as a fetus.

[0047]

V (x, y, t) = √ [｛∂Bz (x, y, t) / ∂x｝ 2+ ｛∂Bz (x, y, t) / ∂y｝ 2+ ｛Bz (x , Y, t)｝ 2] (Equation 5) Using V (x, y, t) instead of St (x, y, t), in the same manner as described above, the isomagnetic field map, the equal integration A figure can be obtained.

The magnetic field waveforms St (x, y, t) and V (x, y, t) measured by the SQUID magnetometers are displayed, and the magnetic field distribution map is represented by an isomagnetic field diagram and an equal integration diagram.
Display on the display screen of the display device. The contour map and the isointegral chart are color-coded according to the level of the contour lines, and three-dimensionally displayed to obtain data useful for diagnosis.

That is, the magnetic field measuring apparatus of the present invention does not measure the tangential components Bx (x, y, t) and By (x, y, t), but measures the normal component Bz (x, y, t). From the measurement alone, a magnetic field distribution map in which a peak pattern appears immediately above the current source can be obtained. As a result, the positions of multiple current sources in the living body can be read directly, so that myocardial infarction, ischemia, arrhythmia,
It is possible to obtain useful data for diagnosing diseases related to the heart such as diagnosis of myocardial hypertrophy and evaluation of changes in myocardial condition before and after surgery. The magnetic field measuring apparatus of the present invention can measure and display data (magnetic field distribution) for diagnosis of an adult or fetal heart in a short time of about 10 seconds to 5 minutes.

Hereinafter, a typical embodiment will be described in more detail with reference to the drawings.

FIG. 1 is a view for explaining a configuration example of a high magnetic permeability sheet 23 having a high magnetic permeability used in each embodiment of the present invention. FIG. 2 is a perspective view illustrating an example of the arrangement of a high magnetic permeability sheet on a hollow cylinder constituting a magnetic field shielding device in each embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating an example of the arrangement of a high magnetic permeability sheet on a hollow cylinder constituting a magnetic field shielding device in each embodiment of the present invention.

The flexible high magnetic permeability sheet 23 is made of a strip-shaped magnetic material (magnetic material ribbon, magnetic material tape) 2.
5 is sandwiched between the non-magnetic holding sheets 26-1 and 26-2. The high magnetic permeability sheet 23 is the same as the high magnetic permeability sheet described in the related art 2. A soft magnetic amorphous alloy is used as the high magnetic permeability material.

The strip-shaped magnetic material ribbons 25 are arranged so as to overlap on the long sides of adjacent strips, and the long sides of a plurality of strips are arranged almost in parallel. The plurality of magnetic material ribbons 25 are made of a resin having flexibility between the holding sheets 26-1 and 26-2.
Alternatively, it is fixed by the adhesive 24. Holding sheet 26
As a material of -1, 26-2, a PET (polyethylene terephthalate) sheet is typically used. The size of the high magnetic permeability sheet 23 is, for example, 450 cm long and 600 cm wide.
cm.

The soft magnetic amorphous alloy is a Fe—Cu—Nb—Si—B system (Fe: 73.5%, Cu: 1%, Nb: 3%, Si:
(13.5%, B: 9%) alloy, and has an ultrafine crystal structure with a crystal grain boundary size of 100 nm or less.

The thickness of the used magnetic ribbon 25 is about 20.
μm, and the thickness of the holding sheets 26-1 and 26-2 is 30 μm.
The total thickness of the high magnetic permeability sheet 23 is 100 μm. The thickness of the magnetic material ribbon 25 is about 10 μm to 100 μm.
m, the thickness of the holding sheets 26-1 and 26-2 is 10 μm or more.
500 μm, and the total thickness of the high magnetic permeability sheet 23 is 50 μm.
When the thickness is set to 1.5 mm, the attaching and bending work of the high magnetic permeability sheet 23 becomes easy.

The magnetic field shielding device according to each embodiment of the present invention comprises a plurality of magnetic field shielding cylinders 60 arranged coaxially. Each magnetic field shielding cylinder is composed of a high magnetic permeability sheet supporting cylinder 80 having a different inner radius, and a high magnetic permeability sheet layer 8 disposed on the inner peripheral surface and / or outer peripheral surface of the high magnetic permeability sheet supporting cylinder 80.
2

In each magnetic field shielding cylinder, corresponding to each embodiment, a circular third opening 4 for inserting the bottom of the cryostat into the innermost magnetic field shielding cylinder.
3 is formed, and within the patient's field of view placed inside the innermost magnetic field shielding cylinder, a fourth circular opening 44 is formed.
Is formed, and the patient can talk with the doctor in line of sight.

FIG. 2 shows one magnetic field shielding cylinder 60, and a plurality of high magnetic permeability sheets 23 are attached to the outer peripheral surface of the high magnetic permeability sheet supporting cylinder 80 using an adhesive or the like. A layer 82 is formed. The high-permeability sheet supporting cylinder 80 is an aluminum hollow cylinder having an inner radius r and a thickness of 0.5 mm.

The high magnetic permeability sheet 23 is attached by any of the following methods. (1) A plurality of high-permeability sheets 23 are attached so as to have overlapping portions. (2) The upper high permeability sheet 23 is attached so as to cover the overlapping portion of the lower high permeability sheet 23. (3) The method (1) and the method (2) are combined and affixed. Regardless of the method of attachment,
A plurality of high-permeability sheets 23 are laminated and attached so that the magnetic material ribbons 25 overlap each other due to the mutual overlap of the high-permeability sheets 23.

Each high magnetic permeability sheet 23 has a long side of each magnetic material ribbon 25 such that the short side of each magnetic material ribbon 25 is substantially parallel to the center axis of the high magnetic permeability sheet support cylinder 80. Is adhered to the high-permeability sheet support cylinder 80 using an adhesive or the like so as to be substantially parallel to a plane perpendicular to the center axis of the high-permeability sheet support cylinder 80. A plurality of layers of the magnetic susceptibility sheet 23 are formed.

FIG. 3 shows a high magnetic permeability sheet layer 82 formed by two layers of the high magnetic permeability sheet 23. In FIG. 3, the first
The overlap of the high magnetic permeability sheet 23 in each of the layers and the second layer is omitted.

In the magnetic field shielding device according to each embodiment of the present invention, the high magnetic permeability sheet supporting cylinders 80 constituting each of the plurality of magnetic field shielding cylinders 60 arranged coaxially have different inner radii. The interval between the adjacent high-permeability sheet supporting cylinders 80 is 1 cm to 20 cm. According to the configuration of the magnetic field shielding device described above, a plurality of magnetic field shielding cylinders 6 for the external magnetic field are provided.
The component in the direction perpendicular to the central axis of 0 is shielded from the external magnetic field at a high magnetic field shielding rate inside the innermost magnetic field shielding cylinder. In each of the following embodiments, the configuration of a magnetic field shielding device having two magnetic field shielding cylinders is illustrated for simplification of the drawing. However, the configuration of a magnetic field shielding device having two to five magnetic field shielding cylinders may be used. good.

In the following description of each embodiment, the central axis of the plurality of magnetic field shielding cylinders 60 arranged coaxially is referred to as “the central axis of the magnetic field shielding device” for simplicity. Further, in the following description of each embodiment, each of the plurality of magnetic field shielding cylinders 60 is configured to be divided into two portions in the direction perpendicular to the center axis, or to be divided into two portions in the circumferential direction. In the case where these two parts are overlapped with each other and each of the plurality of magnetic field shielding cylinders 60 is formed, a plurality of the magnetic field shielding cylinders 60 are configured to be overlapped and arranged coaxially. The central axis of the magnetic field shielding cylinder is similarly referred to as “the central axis of the magnetic field shielding device”. (Embodiment 1) FIG. 4 is a perspective view showing a configuration example of a biomagnetic field measuring apparatus according to Embodiment 1 of the present invention. FIG. 5 is a perspective view of the magnetic field shielding device 40 shown in FIG. FIG. 6 is a cross-sectional view of a plane passing through the center of the measurement field of view of the biomagnetic field measurement device shown in FIG.

The biomagnetic field measuring device includes a magnetic field shielding device 40,
A cryostat 50 for holding a plurality of SQUID magnetometers 57 for detecting a magnetic field (biomagnetic field) generated from an inspection target (living body) at a low temperature, a gantry 30-2 supporting the cryostat 50, a magnetic field shielding device 40 and a gantry 3
Magnetic field shielding device that supports 0-2, gantry support 30-
1 and a coolant supply device or a cooling device 55 for cooling the inside of the cryostat 50, and a SQ through a coolant supply line or a cooling transmission line 54 and a data collection / sensor control line 51.
The UID magnetometer 57 includes a data collection / sensor control device 52 for controlling the drive of the UID magnetometer 57 and collecting and detecting the detected biomagnetic field, and a single or a plurality of display devices 53 for displaying the result of the data processing.

The inside of the cryostat 50 contains liquid H supplied from a refrigerant supply device 55 through a refrigerant supply line 54.
e, or cooled by supplying a He gas cooled by a compressor via a cooling transmission line 54 using a refrigerator as a cooling device 55 to a cold head disposed inside the cryostat 50. You.

The magnetic field shielding device 40 is composed of a plurality of magnetic field shielding cylinders 60 described with reference to FIGS. 2 and 3, and has a first opening 41 in the positive direction of the central axis (y direction) of the plurality of magnetic field shielding cylinders.
And a third opening 4 penetrating a plurality of magnetic shielding cylinders for inserting the second opening 42 in the negative direction of the y direction and the cryostat 50 in the upper part in the direction perpendicular to the central axis (z direction).
3 has a fourth opening 44 penetrating a plurality of magnetic field shielding cylinders for observing an inspection object lying on the bed 20. Central axis of multiple magnetic shielding cylinders (y direction)
(The central axis of the magnetic field shielding device 40) is horizontal to the floor surface.

The magnetic field shielding device 40 shields a component of the external magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device 40 with a high magnetic field shielding ratio inside the innermost magnetic field shielding cylinder 60-1. As a result, the SQUID magnetometer 57 can detect the z-direction component of the biomagnetic field generated inside the magnetic field shielding device 2 with high sensitivity.

The height of the gantry 30-2 is controlled and fixed by the gantry height control device 31, and the inspector (doctor) 35
Operates the gantry height control box 32 while observing the positional relationship between the inspection site of the inspection object (patient) 36 lying on the bed 20 from the fourth opening 44 and the bottom surface of the cryostat 50. Gantry height control box 32
, The gantry height control device 31 is controlled, and the position of the bottom surface of the cryostat 50 in the z direction is fixed. The x direction is set to a direction orthogonal to the y direction and the z direction.

A plurality of SQs arranged in a plane (measurement plane) parallel to the xy plane near the bottom inside the cryostat 102
The UID magnetometer 57 is driven by the FLL circuit of the data collection / sensor control device 52. The FLL circuit is
A biomagnetic signal detected by the SQUID magnetometer 57 is output. The output of the FLL circuit is filtered, amplified, converted into digital data by an AD converter, and stored in the storage device of the data collection processing / sensor control device 52. As a result of the data processing by the data collection processing / sensor control device 52, for example, the magnetic field waveform St (x, y,
An isomagnetic field diagram, an equal integration diagram, and the like based on t) ((Equation 3)) and V (x, y, t) ((Equation 5)) are displayed on the display screen of the display device 53.

The bed 20 on which the inspection object 36 is mounted is x
The x and y direction moving devices 21 are mounted on a support 22 of the x and y direction moving devices. The bed 20 is disposed inside the innermost magnetic field shielding cylinder of the magnetic field shielding device 40.

It is to be noted that an x, y, and z direction moving device can be used instead of the x and y direction moving device 21 with the height of the bottom surface of the cryostat 50 being a fixed position. In this case, the gantry 30-2 and the magnetic shielding device 4
The gantry 3 is positioned such that the measurement surface on which the detection coils of the plurality of SQUID magnetometers 57 are arranged substantially coincides with the central axis of the innermost magnetic field shielding cylinder 60-1.
The position of 0-2 is fixed, or the gantry 30-2 and the magnetic field shielding device / gantry support 30-1 are integrally formed. Of course, the gantry height control device 31 and the gantry height control box 32 are not required.

The inspector (physician) 35 controls the height of the gantry while observing the positional relationship between the inspection site (the patient) 36 on the bed 20 and the bottom surface of the cryostat 50 from the fourth opening 44. Instead of the box 32, an x, y, z movement control box (not shown) of the bed 20 is operated. The x, y, and z direction moving devices of the bed 20 are controlled by signals from the x, y, and z direction movement control boxes, and the positions of the bed 20 in the x, y, and z directions are fixed.

In the above explanation, the inspector (doctor) 35
Although the patient 36 is observed through the fourth opening 44, it goes without saying that the patient 36 may be observed through the first opening 41 or the second opening 42 as a configuration without the fourth opening 44.

The fourth opening 44 provided in the field of view of the patient 36 gives the patient 36 a sense of openness, and the examiner (physician) 35 can interact with the patient 36 through the fourth opening 44 in close proximity. The patient's condition can be accurately observed. The examiner (physician) 35 can easily transmit instructions to the patient 36. The patient 36 passes through the fourth opening 44 through the magnetic shielding device 4.
0 can be seen outside, which has the effect of reducing psychological anxiety and the like.

As shown in FIG. 5, the center axis of the third opening 43 passing through the plurality of magnetic field shielding cylinders and the center axis of the fourth opening 44 passing through the plurality of magnetic field shielding cylinders are approximately 45 degrees. At an angle. As shown in FIG. 6, SQUID magnetometers 57 are two-dimensionally arranged at the bottom inside the cryostat 50.
Is satisfied.

The magnetic field shielding cylinder 60 is composed of a first magnetic field shielding cylinder 60-1 and a second magnetic field shielding cylinder 60-2. The space between the first magnetic field shielding cylinder 60-1 and the second magnetic field shielding cylinder 60-2 is filled with a filler 70, and the first magnetic field shielding cylinder 60-1 and the second magnetic field shielding cylinder 60- 2 is stably maintained. In the example shown in FIG.
0 is filled in the lower half, but the third opening 43,
The upper half portion excluding the fourth opening 44 may be filled. As the filler 70, hard polyurethane containing a foaming agent or the like can be used. Rigid polyurethane containing a foaming agent
Because of its light weight, the first magnetic field shielding cylinder 60- can be filled even in the upper half except for the third opening 43 and the fourth opening 44.
First, the shape of the second magnetic field shielding cylinder 60-2 is not deformed. (Embodiment 2) FIG. 7 is a perspective view showing a configuration example of a biomagnetic field measuring apparatus according to Embodiment 2 of the present invention. FIG. 8 is a perspective view of the magnetic field shielding device shown in FIG. FIG. 9 is a cross-sectional view taken along a plane passing through the center of the measurement field of view of the biomagnetic field measuring apparatus shown in FIG. 7, and includes a partially enlarged cross section.

The following description focuses on differences from the first embodiment. In the configuration of the biomagnetic field measuring apparatus according to the second embodiment,
Is divided into two in the y direction,
It is composed of a first portion 40-1 of the magnetic field shielding device and a second portion 40-2 of the magnetic field shielding device. The first of magnetic field shielding device
Is a second part 40-2 of the magnetic shielding apparatus.
Is configured to be movable in the y direction. As in the first embodiment, the gantry 30-2 and the second part 40-2 of the magnetic field shield device are supported by the magnetic field shield device / gantry support 30-1.

The first part 40-1 of the magnetic field shielding device is supported and fixed on the magnetic field shielding device support 92, and a plurality of wheels 91 arranged below the magnetic field shielding device support 92 are mounted on the floor 11.
7 are mounted on rails 90-1 and 90-2 arranged on the surface of No. 7. The first part 40-1 of the magnetic shielding apparatus is
It can move in the y direction on the rails 90-1 and 90-2.
By this movement, the first portion 40-1 of the magnetic field shielding device can be separated from the second portion 40-2 of the magnetic field shielding device.

As a result, in the open space, the doctor 35 can mount the patient 36 on the bed 20 in a comfortable posture, or the patient 36 can lie down on the bed 20 easily. The patient is mounted so that the foot first passes under the cryostat and eventually the chest reaches the bottom of the cryostat. The doctor 35 can efficiently adjust the positional relationship between the examination site of the patient 36 and the bottom surface of the cryostat 50. After adjustment, the first part 40 of the separated magnetic shielding apparatus
-1 to move the first part 40-1 of the magnetic shielding apparatus.
The third opening 43 and the fourth opening 44 can be formed by overlapping the magnetic field shielding device with the second portion 40-2 in the y direction.

As a result, the component of the extraneous magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device 40 is converted to the innermost magnetic field shielding cylinder 4.
0-1-1 and 40-2-1 can be shielded with a high magnetic field shielding ratio. In a space where an extraneous magnetic field is shielded with a high magnetic field shielding ratio, a component in the z direction of the biomagnetic field from the examination site can be detected with high sensitivity.

As shown in FIG. 8, the magnetic field shielding cylinder constituting the first portion 40-1 of the magnetic field shielding device and the magnetic field shielding cylinder constituting the second portion 40-2 of the magnetic field shielding device are respectively overlapped. It has a notch having a part of the circumference so that the third opening 43 and the fourth opening 44 are formed at the time.

As shown in FIG. 9, the magnetic field shielding device 40
It comprises a first portion 40-1 of the magnetic field shielding device and a second portion 40-2 of the magnetic field shielding device. The first part 40-1 of the magnetic field shielding device is a first magnetic field shielding inner cylinder 40-1.
-1, the first magnetic field shielding outer cylinder 40-1-2. The second part 40-2 of the magnetic field shielding device is composed of a second magnetic field shielding inner cylinder 40-2-1 and a second magnetic field shielding outer cylinder 40-2-2.

The first magnetic field shielding outer cylinder 40-1-2 is overlapped inside the second magnetic field shielding outer cylinder 40-2-2, and the second magnetic field shielding inner cylinder 40-2-1 is provided. , A first magnetic field shielding inner cylinder 40-1-1 is arranged in an overlapping manner. FIG. 9 shows a third opening at this overlapping portion.

As shown in the enlarged cross section, the second magnetic field shielding inner cylinder 40-2-1 and the second magnetic field shielding outer cylinder 40-2
The high permeability sheet layer 82 is formed by the high permeability sheet 23 inside each high permeability sheet supporting cylinder 80 of -2. A high magnetic permeability sheet 23 and a high magnetic permeability sheet layer 82 are provided outside the high magnetic permeability sheet support cylinders 80 of the first magnetic field shielding inner cylinder 40-1-1 and the first magnetic field shielding outer cylinder 40-1-2. Are formed. As a result, at the overlap,
The configuration in which the high magnetic permeability sheet layer 82 is brought close to the structure reduces the leakage magnetic flux to enhance the magnetic field shielding effect.

Further, the second magnetic field shielding outer cylinder 40-2-2 and the first magnetic field shielding outer cylinder 40-1 outside the third opening in a direction parallel to the central axis of the magnetic field shielding device 40. −
2, the second magnetic field shield inner cylinder 40-2
The distance at which -1 and the first magnetic field shielding inner cylinder 40-1-1 overlap is about 1/2 to about 1/4 of the diameter of the third opening. The overlapping portion is made sufficiently large to enhance the magnetic field shielding effect.

The bed 20 on which the bed 20, the x- and y-direction moving devices 21 are mounted, and the support base 22 of the moving device are connected via a spacer 140-1 to the second magnetic field shielding inner cylinder 40-2-.
1. For the same purpose as in the first embodiment, the second
The filler 70-1 is filled in the lower half between the magnetic field shielding inner cylinder 40-2-1 and the second magnetic field shielding outer cylinder 40-2-2, and the first magnetic field shielding inner cylinder 40-1 is filled. -1 and first
The lower half between the magnetic field shielding outer cylinders 40-1-2 is filled with a filler 70-2. In the example shown in FIG.
Although 0-1 and 70-2 are filled in the lower half, it goes without saying that the upper half excluding the third opening 43 and the fourth opening 44 may also be filled.

As in the first embodiment, the height of the bottom surface of the cryostat 50 is set to a fixed position, and x and y are set.
It goes without saying that the x, y, z direction moving device of the bed 20 can be used instead of the direction moving device 21. Further, as in the first embodiment, it is needless to say that the fourth opening may be omitted. (Embodiment 3) FIG. 10 is a perspective view showing a configuration example of a biomagnetic field measuring apparatus according to Embodiment 3 of the present invention. FIG. 11 is a perspective view of the magnetic field shielding device shown in FIG. 10 and includes a partially enlarged cross section.
FIG. 12 is a cross-sectional view for explaining how a test object (patient) is taken in and out of the biomagnetic field measuring apparatus shown in FIG. 7, and includes a partially enlarged cross section.

The following description focuses on differences from the first embodiment. The magnetic field shielding device 40 described in the first embodiment is divided into two parts in the circumferential direction, and is configured by a first portion 40-3 of the magnetic field shielding device and a second portion 40-4 of the magnetic field shielding device. The first portion 40-3 of the magnetic field shielding device is configured to be movable in the circumferential direction with respect to the second portion 40-4 of the magnetic field shielding device. As in the first embodiment, the gantry 30-2 and the second portion 40-4 of the magnetic field shield device are supported by the magnetic field shield device / gantry support 30-1.

As shown in FIGS. 11 and 12, the first portion 40-3 of the magnetic field shielding device is connected by a connecting plate 150-1 at the positive and negative ends in the y direction. , And a second magnetic field shielding outer cylinder 40-3-2. Similarly, the second part 40-4 of the magnetic field shielding device of the magnetic field shielding device is joined by a coupling plate 150-2 (not shown) at the positive and negative ends in the y direction. Magnetic field shielding inner cylinder 40-4-1,
It comprises a second magnetic field shielding outer cylinder 40-4-2.
As shown in FIGS. 10, 11, and 12, a first magnetic field shielding inner cylinder 40-3-1 and a second magnetic field shielding outer cylinder 40-3-1.
A fourth opening 40 penetrating 3-2 is formed.

The inside of the first magnetic field shielding inner cylinder 40-3-1 of the fourth opening 40 and the second magnetic field shielding outer cylinder 4
The outer sides of 0-3-2 are each covered with a transparent curved plate, and the circumferential movement of the first part 40-3 of the magnetic shielding apparatus with respect to the second part 40-4 of the magnetic shielding apparatus. At the time of, do not pinch your hands, clothes, etc.

The first part 40-3 of the magnetic field shield device is approximately 1
The second part 40 of the magnetic shielding apparatus has a circumference of 10 degrees.
-4 has a circumference of about 270 degrees, and is mutually overlapped at both ends in a range of about 10 degrees. That is, the first
Magnetic field shielding inner cylinder 40-3-1, second magnetic field shielding inner cylinder 40-4-1 and second magnetic field shielding outer cylinder 40
-3-2 and the second magnetic field shielding outer cylinder 40-4-2 respectively close the magnetic field shielding device in a closed state when overlapping at about 10 degrees at both ends parallel to the central axis of the magnetic field shielding device. When it is formed and overlaps in a range of about 110 degrees, it has an opening and forms an open magnetic field shielding device. In the closed state, the overlapping portion is made sufficiently large to enhance the magnetic field shielding effect.

On the outer peripheral surface of the high magnetic permeability sheet supporting cylinder 80 of the second magnetic field shielding outer cylinder 40-3-2, a T-shaped elongated plate as a guide 105-2 is shown as an enlarged cross section. And a second magnetic field shielding outer cylinder 40-4
A T-shaped elongated groove for receiving the guide 105-2 is formed on the inner peripheral surface of the high-permeability sheet supporting cylinder 80-2.

Similarly, the first magnetic field shielding inner cylinder 40-3
A T-shaped elongated plate is arranged as a guide 105-1 on the outer peripheral surface of the high-permeability sheet supporting cylinder of No. -1, and the high magnetic permeability of the second magnetic field shielding inner cylinder 40-4-1. A T-shaped elongated groove (not shown) for receiving the guide 105-1 is formed on the inner peripheral surface of the magnetic susceptibility sheet support cylinder.

The high-permeability sheet layer 82 is formed by the high-permeability sheet 23 so that the second magnetic-field-shield inner cylinder 40-4- is formed.
1. The first magnetic field shielding inner cylinder 40 is provided on the outer surface of each high magnetic permeability sheet supporting cylinder of the second magnetic field shielding outer cylinder 40-4-2.
3-1 and the second magnetic field shielding outer cylinder 40-3-2 are formed on the inner surface of each high magnetic permeability sheet supporting cylinder.

As shown in FIG. 11, the first magnetic field shielding device
The magnetic field shielding cylinder constituting the portion 40-3 of the above and the magnetic field shielding cylinder constituting the second portion 40-4 of the magnetic field shielding device respectively form a third opening 43 when overlapped.
It has a notch with a part of the circumference.

FIG. 12A shows a state where the patient 36 lies on the bed 20 and the biomagnetic field from the examination site is measured. The magnetic field shielding cylinder constituting the first portion 40-3 of the magnetic field shielding device and the magnetic field shielding cylinder constituting the second portion 40-4 of the magnetic field shielding device are respectively overlapped. The positional relationship between the first part 40-3 and the second part 40-4 is fixed by a lock. In this state, the component of the external magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device 40 can be shielded at a high magnetic field shielding rate inside the innermost magnetic field shielding cylinders 40-3-1 and 40-4-1. In a space where an extraneous magnetic field is shielded with a high magnetic field shielding ratio, a component in the z direction of the biomagnetic field from the examination site can be detected with high sensitivity.

FIG. 12 (b) shows that the first portion 40-3 of the magnetic field shielding device is rotated manually or automatically using a handle (not shown) attached to the first portion 40-3. Direction, the position of the first portion 40-3 is locked, an opening is formed, and an open space is formed in an angle range of about 90 degrees. As a result, in the open space, the doctor 35 moves the patient 36 from the bed moving table 103 to the bed 2 in a comfortable posture.
0 or the patient 36 can easily lie on the bed 20, and the doctor 35 can efficiently adjust the positional relationship between the examination site of the patient 36 and the bottom surface of the cryostat 50.

As in the first embodiment, the height of the bottom surface of the cryostat 50 is set to a fixed position, and x and y are set.
It goes without saying that the x, y, z direction moving device of the bed 20 can be used instead of the direction moving device 21. Further, as in the first embodiment, it is needless to say that the fourth opening may be omitted. (Embodiment 4) A biomagnetic field measuring apparatus according to Embodiment 4 of the present invention
A part of the configuration of the biomagnetic field measuring apparatus according to the third embodiment is changed.
This is a bedside biomagnetic field measurement device configured to be movable to the vicinity of a bed in a hospital room.

A plurality of wheels 100 are movably arranged on the magnetic field shielding device / gantry support 30-1. A plurality of wheels 100 are also movably mounted on the bed and the support 22 of the moving device. Wheels 29-1, 29-2, 29-
3, 29-4 (not shown) are arranged. A data collection processing / sensor control device 52, a display device 53, a refrigerant supply device or a cooling device 5
5 is mounted.

In the bedside biomagnetic field measuring apparatus according to the fourth embodiment, the height of the bottom surface of the cryostat 50 is set to a fixed position, and the x, y, and z directions of the bed 20 are used instead of the x and y direction moving devices 21. The moving device 21 'is used.

As shown in FIG. 12C, the wheels 29'-
1, 29'-2, 29'-3 (not shown), 29'-4
(Not shown), and after moving the bedside biomagnetism measuring device to the vicinity of the bed moving table 103 to be mounted, as shown in FIG. -3 is moved in the circumferential direction, the position is locked, and an open space is formed in an angle range of about 90 degrees.

The x, y, z direction moving device 21 ′ of the bed 20 of the bedside biomagnetic field measuring device and the bed 20-1, x, y, z direction moving device 21 ′ of the bed moving table 10.
And the bed 2 in each of the x, y, and z directions.
0 and the position of the bed 20-1 are adjusted so that the patient 3
6 can be moved from the bed 20-1 to the bed 20.

Using the bed 20-1, x, y, z direction moving device 21 ', the doctor 35 adjusts the positional relationship between the examination site of the patient 36 and the bottom surface of the cryostat 50.
Thereafter, in the state shown in FIG. 12A, the biomagnetic field from the examination site of the patient 36 is measured. After the measurement of the biomagnetic field, x and x of the bed 20 are set as shown in FIG.
The bed 20 in each of the x, y, and z directions using the y, z direction moving device 21 'and the bed 20-1, x, y, z direction moving device 21' of the bed moving table 10. The patient 36 can be easily moved from the bed 20 to the bed 20-1 by adjusting the position of the bed 20-1.

The biomagnetic field measuring device for a bedside according to the fourth embodiment can be freely moved, and can be moved in a hospital to perform an examination of a hospitalized patient at the bedside. Therefore, emergency patients,
When measuring a bedridden patient, the patient does not need to move to the laboratory where the biomagnetic measurement device is installed,
The burden on the patient is reduced. (Embodiment 5) FIG. 13 shows an embodiment of Embodiment 5 of the present invention, and a medical examination vehicle (mobile biomagnetic field measuring apparatus) in which the biomagnetic field measuring apparatus described in Embodiment 3 or 4 is mounted on an automobile.
It is a perspective view including the partially broken part which shows the example of FIG. The entire biomagnetic field measuring device is mounted on a vibration isolation table 11 placed on a floor 110 in the vehicle.
It is arranged and fixed on 1 to block external vibration. The vehicle has an anchor 112 for fixing, and when measuring the biomagnetic field, the anchor 112 is lowered to the ground to fix the vehicle to the ground. This medical checkup car is moved to local communities such as schools and public health centers and used for periodic group checkups. (Embodiment 6) FIG. 14 is a perspective view showing a configuration example of a magnetic field shielding device used in a biomagnetic field measuring apparatus according to Embodiment 6 of the present invention, and includes a partly enlarged view. FIG. 15 is a cross-sectional view taken along a plane passing through the center of the measurement field of view of the biomagnetic field measurement device using the magnetic field shielding device shown in FIG.

In the magnetic field shielding device shown in FIG. 14, the magnetic field shielding device 40 described in the first embodiment is divided into two parts in the circumferential direction, and the first part 40-5 of the magnetic field shielding device and the second part of the magnetic field shielding device It is constituted by the portion 40-6. The first portion 40-5 of the magnetic field shielding device is configured to be movable in the circumferential direction with respect to the second portion 40-6 of the magnetic field shielding device.

A plurality of wheels 118 are fixed to the lower portion of the second magnetic field shielding inner cylinder 40-6-1 and the second magnetic field shielding outer cylinder 40-6-2, as shown in the enlarged cross section of FIG. In addition, the wheels 118 are arranged inside moving guide grooves 119 formed on the floor 117. Second magnetic field shielding inner cylinder 40-6-1, second magnetic field shielding outer cylinder 40-6-1
The upper portions of 2 are connected by a connecting plate 115. An upper connecting portion 116 for movement for connection to a circular guide rail arranged on the ceiling is fixed to the connecting plate 115.

As shown in the enlarged cross section of FIG. 14, the inside of each high magnetic permeability sheet supporting cylinder 80 of the second magnetic field shielding inner cylinder 40-6-1 and the second magnetic field shielding outer cylinder 40-6-2. The high permeability sheet layer 82 is formed of the high permeability sheet 23. First magnetic field shield inner cylinder 40-5
1. A high-permeability sheet layer 82 is formed by a high-permeability sheet 23 outside each high-permeability sheet supporting cylinder 80 of the first magnetic field shielding outer cylinder 40-5-2. As a result,
The high magnetic permeability sheet layer 82 is arranged close to the overlapping portion to reduce the leakage magnetic flux and enhance the magnetic field shielding effect.

As shown in FIG. 15, the first magnetic field shielding inner cylinder 40-5-1 is formed by the magnetic field shielding cylindrical support 128.
The second magnetic field shielding outer cylinders 40-5-2 are fixed to the floor 117 by the magnetic field shielding cylindrical supports 120, respectively. S
The cryostat 50-1 on the side where the QUID magnetometers 57 are two-dimensionally arranged is movably fixed to the gantry 124. The positional relationship between the examination site of the patient 36 sitting on the chair 122 movable in the x and y directions and the surface of the cryostat 50-1 on which the SQUID magnetometer 57 is arranged, and the height of the cryostat 50-1 After the position is adjusted, the cryostat 50-1 is fixed by the cryostat position fixing lock 126.

The height of the second part 40-6 of the magnetic shielding apparatus is higher than the height of the first part 40-5 of the magnetic shielding apparatus, and the height of the second part 40-6 of the magnetic shielding apparatus is increased. The structure for rotating is simplified. The second part 40-6 of the magnetic shielding apparatus has a circumference of about 200 degrees, and the first part 40-5 of the magnetic shielding apparatus has a circumference of 180 degrees, and each has a circumference of about 180 degrees. It is configured to overlap in the range of 10 degrees. That is, the first magnetic field shielding inner cylinder 40-5-1 and the second
Magnetic field shielding inner cylinder 40-6-1, the second magnetic field shielding outer cylinder 40-5-2, and the second magnetic field shielding outer cylinder 40
-6-2 respectively form a closed magnetic field shielding device when overlapping at about 10 degrees at both ends parallel to the central axis of the magnetic field shielding apparatus, and when overlapping at about 180 degrees, An open magnetic field shielding device is formed.

In the closed state, the overlapping portion is made sufficiently large to enhance the magnetic field shielding effect, and the component of the external magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device 40 is reduced to the innermost magnetic field shielding cylinder 40.
Inside of -5-1 and 40-6-1 can be shielded with a high magnetic field shielding ratio. In a space where an extraneous magnetic field is shielded with a high magnetic field shielding ratio, a component in the x direction of the biomagnetic field from the examination site can be detected with high sensitivity.

When the second part 40-6 of the magnetic field shielding device is rotated to create an open space, and the patient 36 is sitting on the chair 122, the physician checks the examination site of the patient 36 and the outer surface of the cryostat 50-1. Adjust the positional relationship of.

The center axis of each magnetic field shielding cylinder 60 constituting the magnetic field shielding device used in the sixth embodiment is arranged coaxially, and each magnetic field shielding cylinder is divided by a plane parallel to the central axis. Each magnetic field shielding cylinder is arranged vertically. In the magnetic field shielding device used in the sixth embodiment, the patient 36 can easily enter the inside of the magnetic field shielding device, and the positioning of the examination site can be performed efficiently. The magnetic field shielding device used in the sixth embodiment is small, and the installation area of the biomagnetic field measuring device can be small.

Note that, assuming that the height of the cryostat 50-1 is a fixed position, instead of the x- and y-direction moving devices, x, y for controlling the x, y, and z directions of the chair 122 on which the inspection target 36 sits. , SQ using the
Cryostat 5 on the side where UID magnetometer 57 is arranged
It goes without saying that the alignment between the plane 0-1 and the plane of the inspection site of the inspection target 36 can be performed. (Embodiment 7) FIG. 16 shows a seventh embodiment of the present invention.
FIG. 16 is a cross-sectional view of a biomagnetic field measuring apparatus using the magnetic field shielding apparatus shown in FIG. In the biomagnetic field measuring apparatus according to the seventh embodiment, the magnetic field shielding apparatus shown in FIGS. 14 and 15 is disposed on a floor 117-1 that is inclined at an angle of 20 degrees or more and 30 degrees or less with respect to the floor 117. Other configurations are the same as those of the sixth embodiment. (Eighth Embodiment) FIG. 17 is a perspective view showing a configuration example of a biomagnetic field measuring apparatus according to an eighth embodiment of the present invention. FIG. 18 is a cross-sectional view taken along a plane passing through the center of the measurement field of view of the biomagnetic field measurement apparatus shown in FIG.

The following description focuses on the differences from the first embodiment. The magnetic field shield device 40-7 is a magnetic field shield inner cylinder 40-.
7-1, composed of a magnetic field shielding outer cylinder 40-7-2,
The magnetic shielding apparatus 40-7 is held by a magnetic shielding apparatus support 130 fixed to the floor 117.

In the eighth embodiment, a small-sized cryostat can be used because a flat type SQUID magnetometer in which a detection coil for detecting a magnetic field is a thin film is used. Example 8
In the configuration of the magnetic field shielding device 40 described in the first embodiment,
The third opening 43 for inserting the cryostat 50 is not formed, and the cryostat 50-2 in which the SQUID magnetometer is arranged two-dimensionally at the bottom is attached to the magnetic field shielding inner cylinder 40-7-.
1 inside. The cryostat 50-2 is held by a cryostat holding plate 132, and the cryostat holding plate 132 is held by a fixed base 131 of the cryostat holding plate fixed to the floor 117.

The bed 20 on which the bed 20, the x and y direction moving devices 21 are mounted, and the support 22 of the moving device are disposed inside the magnetic field shielding inner cylinder 40-7-1 via the spacer 140-2. In the example shown in FIG. 18, the filler 70-3 is filled in the lower half, but it goes without saying that the filler in the upper half may be further filled.

In the eighth embodiment, since the third opening described in the first embodiment is not formed, the component of the extraneous magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device 40 is removed.
Inside 0-7-1, it is possible to shield with a higher magnetic field shielding ratio than the magnetic field shielding device shown in the first embodiment. In a space where an extraneous magnetic field is shielded with a higher magnetic field shielding ratio, a component in the z direction of the biomagnetic field from the inspection site can be detected with high sensitivity.

The patient placed on the bed 20 is moved from the second opening 42 to the inside of the magnetic field shielding inner cylinder 40-7-1, more preferably, so that the foot first passes under the cryostat 50-2. The chest is then inserted with the chest reaching the lower part of the cryostat, with a minimum of pressure. Of course, as shown in FIG. 18, the magnetic field shielding inner cylinder 40-7-
1 may be carried inside. The doctor describes the positional relationship between the examination site of the patient 36 and the bottom surface of the cryostat 50-2.
After adjusting using the x and y direction moving device 21 of the bed 20 and the height direction moving device (position adjusting device) incorporated in the fixed base 131 of the cryostat holding plate, the biomagnetic field from the examination site is measured. I do.

As in the first embodiment, the x, y, z direction moving device of the bed 20 can be used in place of the x, y direction moving device 21 with the height of the cryostat 50-2 being a fixed position. Needless to say. Further, as in the first embodiment, it is needless to say that the fourth opening may be omitted. (Embodiment 9) FIG. 19 is a view showing an example of a magnetic field waveform measured by the biomagnetic field measuring apparatus shown in Embodiment 1 of the present invention. FIG. 19 shows a magnetic field generated from a healthy person's heart detected using a total of four channels of SQUID magnetometers arranged at the vertices of a square at the bottom inside the cryostat, and shows a magnetic field waveform of one channel. The horizontal axis in FIG. 19 is time (sec), and the vertical axis is the differential value (pT /
m).

The configuration of the magnetic field shielding device 40 used for obtaining the measurement result of the eighth embodiment is as follows. The magnetic field shielding device used is composed of first, second and third magnetic field shielding cylinders 60 arranged coaxially from the inside to the outside, and the high magnetic permeability sheet supporting cylinder 80 is provided with a high magnetic permeability outside. Sheet 2
3, a high permeability sheet layer 82 was formed. The magnetic field shielding device used did not have the fourth opening. The third opening has a radius of 30 in order to insert a circular cryostat in which a 4-channel SQUID magnetometer is arranged.
cm round.

Each of the first magnetic field shielding cylinder, the second magnetic field shielding cylinder, and the third magnetic field shielding cylinder has an inner radius of 80c.
An aluminum hollow cylinder having a thickness of 0.5 mm and a length of 200 cm having a m, 90 cm and 100 cm was used. The third opening was provided at the center in the longitudinal direction of each hollow cylinder.

As the high magnetic permeability sheet 23 used, a commercial product (Hitachi Metals Co., Ltd., trade name: Finemet) was used.
The high magnetic permeability sheet 23 has, as a high magnetic permeability material, an ultrafine crystal structure in which the size of a crystal grain boundary is 100 nm or less.
Fe-Cu-Nb-S having a maximum relative permeability of 50,000 or more
i-B type (Fe: 73.5%, Cu: 1%, Nb: 3
%, Si: 13.5%, B: 9%).

The structure of the high magnetic permeability sheet used was such that the thickness of the magnetic material ribbon (high magnetic permeability material) 25 was about 20 μm, the thickness of the holding sheets 26-1 and 26-2 was 30 μm, and the total thickness of the high magnetic permeability sheet 23. 100 μm. Area 610cm × 24
The high-permeability sheet 23 of 0 cm was overlapped and attached to the outer peripheral surface of each aluminum hollow cylinder to form a high-permeability sheet layer 82 having a thickness of about 1 mm.

As shown in FIG. 2, the flexible high magnetic permeability sheet 23 is provided so that the short side of the magnetic material ribbon 25 is substantially parallel to the central axis of each hollow cylinder.
Adhering to the peripheral surface of each hollow cylinder using an adhesive so that the long side surrounds the central axis of each hollow cylinder inside and is almost parallel to the plane perpendicular to the central axis of each hollow cylinder, it is highly transparent. A plurality of layers of the magnetic susceptibility sheet 23 were formed.

By using a magnetic field shield device having a simple configuration, the component in the direction perpendicular to the central axis of the magnetic field shield device for the external magnetic field (the central axis of the first, second, and third magnetic field shield cylinders) can be minimized. At the position of the center axis of the inner first magnetic field shielding cylinder,
It was able to attenuate to -35 dB. That is, at the position of the central axis of the innermost first magnetic field shielding cylinder, the component of the external magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device can be attenuated to -35 dB. As a result, the SQUID magnetometer can detect, with high sensitivity, the component in the z direction of the biomagnetic field generated from the examination site of the living body placed inside the magnetic field shielding device.

The magnetic field shielding ratio of the magnetic field shielding device used was 1/56 at the position of the center axis of the magnetic field shielding device.
It turned out that measurement was possible at 0 or more.

The high-permeability sheet 23 is adhered to the peripheral surface of each hollow cylinder so that the long side of the magnetic material ribbon 25 is parallel to the center axis of each hollow cylinder, and a plurality of layers of the high-permeability sheet 23 are formed. When each magnetic field shielding cylinder is formed by forming the magnetic field shielding component, the component of the extraneous magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device is reduced by about-at the position of the central axis of the innermost first magnetic field shielding cylinder. 3
It could be attenuated to 1 dB.

In the configurations of Embodiment 1, Embodiment 2, Embodiment 3, Embodiment 4, Embodiment 5, and Embodiment 8 described above,
When the fourth opening is provided, when the inner diameter of the innermost magnetic field shielding cylinder is about 1 m, the diameter of the fourth opening can be about 30 cm.

In the configuration of the first, second and eighth embodiments, the inspection target (patient) is loaded into the inner space of the innermost magnetic field shielding cylinder of the magnetic field shielding device with the foot first. First, pass the lower part of the cryostat so that the chest finally reaches the lower part of the cryostat so that the feeling of oppression is as small as possible.

[0130]

According to the present invention, it is possible to realize a light-weight, small-sized, low-cost, high-performance, high-magnetic-field shielding device having a high magnetic-field shielding ratio by using a high-permeability sheet having a high magnetic permeability. Since the magnetic field shield device of the present invention is lightweight and small, it does not particularly require load resistance at the place where it is installed, and can be installed if the area is small, and a magnetic field shield device, that is, a magnetic field measurement device is installed. There are no restrictions on locations.

In the magnetic field measuring apparatus according to the present invention, a magnetic field distribution map in which a peak pattern appears immediately above a current source can be obtained only by measuring the normal component of the magnetic field without measuring the tangential components in two directions of the magnetic field. Can be. As a result, it is possible to directly read the position of a plurality of current sources in the test object, particularly in the living body, and thus, when the test object is a living body, it is possible to obtain useful data for diagnosing diseases relating to the heart of adults and fetuses. The magnetic field measuring device of the present invention can measure and display a magnetic field from an inspection target in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a high magnetic permeability sheet having a high magnetic permeability used in each embodiment of the present invention.

FIG. 2 is a perspective view illustrating an arrangement example of a high magnetic permeability sheet on a hollow cylinder constituting a magnetic field shielding device in each embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating an arrangement example of a high magnetic permeability sheet on a hollow cylinder constituting a magnetic field shielding device in each embodiment of the present invention.

FIG. 4 is a perspective view showing a configuration example of a biomagnetic field measuring apparatus according to the first embodiment of the present invention.

5 is a perspective view of the magnetic field shielding device shown in FIG.

FIG. 6 is a cross-sectional view of the biomagnetic field measuring apparatus shown in FIG.

FIG. 7 is a perspective view illustrating a configuration example of a biomagnetic field measurement apparatus according to a second embodiment of the present invention.

FIG. 8 is a perspective view of the magnetic field shielding device shown in FIG. 7;

9 is a cross-sectional view of the biomagnetic field measuring apparatus shown in FIG.

FIG. 10 is a perspective view illustrating a configuration example of a biomagnetic field measurement apparatus according to a third embodiment of the present invention.

11 is a perspective view of the magnetic field shielding device shown in FIG.

FIG. 12 is a cross-sectional view for explaining how a test object (patient) is taken in and out of the biomagnetic field measuring apparatus shown in FIG.

FIG. 13 is an embodiment of the fifth embodiment of the present invention, and is a third embodiment.
Alternatively, a perspective view including a partially broken portion showing an example of a medical examination car in which the biomagnetic field measurement device of the fourth embodiment is mounted on an automobile.

FIG. 14 is a perspective view showing a configuration example of a magnetic field shielding device used in a biomagnetic field measuring device according to a sixth embodiment of the present invention.

FIG. 15 is a cross-sectional view of a biomagnetic field measuring apparatus using the magnetic field shielding apparatus shown in FIG. 14 taken along a plane passing through the center of a measurement visual field.

FIG. 16 is a cross-sectional view of a biomagnetic field measuring apparatus using the magnetic field shielding apparatus shown in FIG.

FIG. 17 is a perspective view illustrating a configuration example of a biomagnetic field measurement apparatus according to an eighth embodiment of the present invention.

FIG. 18 is a cross-sectional view of the biomagnetic field measuring apparatus shown in FIG.

FIG. 19 is a diagram illustrating an example of a magnetic field waveform measured by the biomagnetic field measuring apparatus according to the first embodiment of the present invention.

[Explanation of symbols]

20, 20-1 ... bed, 21 ... x and y direction moving device, or x, y, z direction moving device, 21 '... x, y, z
Direction moving device, 22 ... bed and support for moving device, 2
3: high permeability sheet, 24: flexible resin or adhesive,
25 ... magnetic material ribbon, 26-1, 26-2 ... holding sheet, 29-1, 29-2, 29-3, 29-4 ... wheels,
29'-1, 29'-2, 29'-3, 29'-4: wheels, 30-1: magnetic field shielding device / gantry support, 30-
2 ... Gantry, 31 ... Gantry height control device, 32 ...
Gantry height control box, 35 ... Examiner (doctor),
36 ... test object (patient), 40 ... magnetic field shield device, 40-
1. First part of magnetic field shielding device, 40-1-1 ... first magnetic field shielding inner cylinder, 40-1-2 ... first magnetic field shielding outer cylinder, 40-2 ... second of magnetic field shielding device Part, 40-2
-1 ... second magnetic field shielding inner cylinder, 40-2-2 ... second magnetic field shielding outer cylinder, 40-3 ... first portion of the magnetic field shielding device, 40-3-1 ... first magnetic field shielding inner Cylinder, 40-3
-2: second magnetic field shielding outer cylinder, 40-4: second part of magnetic field shielding device, 40-4-1: second magnetic field shielding inner cylinder, 40-4-2: second magnetic field shielding outer Cylinder, 40-5
... First part of magnetic field shielding device, 40-5-1 ... First magnetic field shielding inner cylinder, 40-5-2 ... Second magnetic field shielding outer cylinder, 40-6 ... Second part of magnetic field shielding device , 40-6-
DESCRIPTION OF SYMBOLS 1 ... 2nd magnetic field shielding inner cylinder, 40-6-2 ... 2nd magnetic field shielding outer cylinder, 40-7 ... Magnetic field shielding apparatus, 40-7-
DESCRIPTION OF SYMBOLS 1 ... Magnetic field shielding inner cylinder, 40-7-2 ... Magnetic field shielding outer cylinder, 41 ... 1st opening, 42 ... 2nd opening, 43 ... 3rd
Opening, 44... Fourth opening, 50, 50-1, 50-2
... cryostat, 51 ... data collection and sensor control line, 52 ... data collection processing and sensor control device, 53 ... display device, 54 ... refrigerant supply line or cooling transmission line, 55 ... refrigerant supply device or cooling device, 56 ... refrigerant, 57 ... SQUID
Magnetic flux meter, 60: magnetic field shielding cylinder, 60-1: first magnetic field shielding cylinder, 60-2: second magnetic field shielding cylinder, 70, 70-
1, 70-2, 70-3: filler, 80: high magnetic permeability sheet support cylinder, 82: high magnetic permeability sheet layer, 90-1, 90
-2 ... rail, 91 ... wheels, 92 ... magnetic shielding apparatus support base, 100, 100-1 ... wheels, 101 ... coupling part, 10
DESCRIPTION OF SYMBOLS 3 ... Bed moving stand, 105 ... Guide, 110 ... Car floor, 111 ... Anti-vibration stand, 112 ... Anchor, 115 ... Connection plate, 116 ... Upper connection part for movement, 117 ... Floor, 1
17-1: inclined floor, 118: wheels, 119: moving guide groove, 120, 128 ... magnetic field shielding cylindrical support, 122
... chair, 124 ... gantry, 126 ... cryostat position fixing lock, 130 ... magnetic field shielding device support, 131
... Cryostat holding plate fixing stand, 132 ... Cryostat holding plate, 140-1, 140-2 ... Spacer,
150-1, 150-2 ... connecting plates.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Go Miyashita 1-280 Higashi Koikekubo, Kokubunji City, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. Central Research Laboratory (72) Inventor Keiji Tsukada 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Hitachi, Ltd.Central Research Laboratories Term (reference) 2G017 AA04 AB01 AC01 AD32 4C027 AA10 CC00 KK00 KK01

Claims (6)

[Claims] 1. A plurality of non-magnetic cylindrical members having a plurality of high-permeability sheets each having a high magnetic permeability, wherein a part of the plurality of high-permeability sheets is overlapped and arranged so as to concentrically surround an axis in a first direction. A cylindrical member having a member and having a first opening at one end in the first direction and a second opening at the other end in the first direction; A third opening penetrating the plurality of tubular members in a direction perpendicular to the axis of the first direction, wherein the plurality of tubular members are connected to the first portion and the first portion in the first direction; And the first part is movable in the first direction with respect to the second part and is separable, and the plurality of cylindrical parts of the first part are separated from each other. The member has a first notch having a semicircular portion opening at an end, and the plurality of cylindrical members of the second portion have a semicircular shape opening at an end. Has a second notch portion having a minute,
The movement of the first portion relative to the second portion in the first direction causes the first notch and the second notch to move perpendicularly to the axis in the first direction. The third opening is formed penetrating the plurality of cylindrical members in a direction, and a space inside the cylindrical member disposed at the innermost side is formed in a direction perpendicular to the first direction of the external magnetic field. A step of moving the first portion in the first direction with respect to the second portion to form an open portion of the magnetic field shielding device in which the component is shielded; Moving the first part into the inner space along the axis in the first direction through the opening, and moving the first part with respect to the second part in the first direction. Closing the opening and inserting it into the third opening formed by closing the opening. Adjusting the positional relationship between the bottom surface of the cryostat holding the plurality of SQUID magnetometers at low temperature and the surface of the living body in a direction perpendicular to the first direction. Detecting a component of a magnetic field generated from the living body in a direction perpendicular to the first direction using a plurality of the SQUID magnetometers. 2. A plurality of non-magnetic cylindrical members having a plurality of high-permeability sheets having a high magnetic permeability, wherein a plurality of the high-permeability sheets are arranged so as to overlap each other, are arranged so as to concentrically surround an axis in a first direction, and have a hollow portion. The cylindrical member provided with a member and having the first opening at one end in the first direction and the second opening at the other end in the first direction. A part of each of the cylindrical members of the magnetic field shielding device, in which a component of a foreign magnetic field in a direction perpendicular to the first direction is shielded in a space inside the cylindrical member disposed at the first position; Forming an open portion by moving in either the circumferential direction surrounding the axis of the direction or the direction intersecting the first direction; and mounting the living body on the living body mounting apparatus, or Loading a living body mounted device into which the magnetic shielding apparatus is carried through the opening, Closing the open portion by moving a part of the cylindrical member in any one of the first direction, a circumferential direction surrounding the axis in the first direction, and a direction intersecting the first direction. And a bottom surface of a cryostat that is inserted into a third opening formed by closing the opening and whose bottom surface is spatially arranged on the inner side and that holds a plurality of SQUID magnetometers at a low temperature; Adjusting the positional relationship in a direction perpendicular to the first direction, and detecting a component of a magnetic field generated from the living body in a direction perpendicular to the first direction by a plurality of SQUID magnetometers. A magnetic field measurement method comprising: 3. The magnetic field measuring method according to claim 2, wherein
The magnetic field measurement method, wherein the living body is mounted on the living body mounting device through the opening from a direction crossing the axis of the first direction. 4. A magnetic field measuring method according to claim 2,
The living body mounting device on which the living body is mounted is carried into the inner space through the opening from a direction substantially parallel to the first direction or a direction crossing an axis of the first direction. A method for measuring a magnetic field, comprising: 5. A plurality of non-magnetic cylindrical members having a plurality of high-permeability sheets each having a high magnetic permeability and arranged so as to overlap each other, concentrically surrounding an axis in a first direction, and having a hollow portion. The cylindrical member, which is provided on the innermost side, has a first opening at one end in the first direction, a second opening at the other end in the first direction, and a first opening. A third opening penetrating through the plurality of cylindrical members in a direction perpendicular to the axis of the direction, and in the space inside the cylindrical member arranged at the innermost position in the first direction of the external magnetic field. In the space inside the magnetic field shielding device in which the component in the vertical direction is shielded, the living body is mounted on the living body mounted device, or the living body mounted device on which the living body is mounted is carried into the inner space. Process and multiple SKUs
Arranging the bottom surface of the cryostat that holds the ID magnetometer at a low temperature so as to face the surface of the living body, and using the plurality of SQUID magnetometers in a direction perpendicular to the first direction of the magnetic field generated from the living body. Detecting a component. 6. A plurality of non-magnetic cylindrical members having a plurality of high-permeability sheets each having a high magnetic permeability and arranged in an overlapping manner, concentrically surrounding an axis in a first direction, and having a hollow portion. The high-permeability sheet is formed of a magnetic material having a high magnetic permeability in the form of a strip sandwiched between non-magnetic holding sheets, and a plurality of the strips are adjacent to a long side of the strip. And the long sides of the strips are arranged substantially in parallel,
The short sides of the plurality of strips of each of the high magnetic permeability sheets are arranged substantially parallel to the axis in the first direction, and the high magnetic permeability sheet is attached to the surface of each of the plurality of cylindrical members by the high magnetic permeability. The long sides of the plurality of strips of the sheet are held so as to surround the axis in the first direction inward, and the innermost cylindrical member has a first opening at one end in the first direction. Is provided with a second opening at the other end in the first direction, and in the space inside the cylindrical member disposed at the innermost position, the first
A living body is mounted on a living body mounted device in the space inside the magnetic field shielding device in which a component in a direction perpendicular to the direction is shielded, or the living body mounted device on which the living body is mounted is mounted on the inner side. Process to be brought into space and multiple SQUIDs
Arranging the bottom surface of the cryostat so as to face the surface of the living body in the inner space where the bottom surface of the cryostat holding the magnetometer at a low temperature is arranged, and generating the plurality of SQUID magnetometers from the living body. Detecting a component of the magnetic field to be applied in a direction perpendicular to the first direction.