JP3454254B2 - Magnetic field measurement device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quantum interference device (SQUID: super) for detecting a magnetic field generated from an inspection object with high sensitivity.
The present invention relates to a magnetic field shield device for performing measurement using a plurality of magnetometers including conducting quantum interference devices), a magnetic field measurement method using the same, and a magnetic field measurement device. The present invention particularly relates to a magnetic field shielding device for measuring a biomagnetic field generated by myocardial activity of the heart of a living body, and
The present invention relates to a biomagnetic field measuring method and a biomagnetic field measuring apparatus using this.

[0002]

2. Description of the Related Art A magnetic shield has been reported in which a plurality of cylindrical shields having different diameters are sequentially arranged concentrically, and a gap is formed between the respective cylindrical shields (prior art 1: Japanese Patent Laid-Open No. Hei 9).
-214166 gazette).

In the technique described in Prior Art 1, the thickness is 0.1
mm-0.5mm, width 20cm-50cm made of tape-shaped Permalloy magnetic shield material, spirally wound magnetic shield material with a lightweight plastic cylinder as core Is 5 cm to 10 cm and is formed into a cylindrical shape.
The overlapping portion is substantially two to five layers and is spirally wound so that the total thickness thereof is about 0.5 mm to 3 mm. Further, rivets are provided in the overlap portion at intervals of 30 cm in the circumferential direction and fixed by tightening, and the adhesive surface of the overlap portion is in contact with metal.

Prior art 1 describes that as a conventional technique, a shielded room such as a prefabricated room is manufactured by using a large number of sheets of permalloy, which is a Ni--Fe alloy material having a high magnetic permeability. However, this conventional technique has a problem that it takes a long time to manufacture the magnetic shield, the number of parts is large, and the magnetic shield becomes very expensive. There is a statement that the price of magnetic shields is desired to be large.

It has been reported that a lightweight shield room is manufactured by using a magnetic shield sheet in which a film of a soft magnetic amorphous alloy and a polymer film are bonded together as a magnetic shield material instead of a permalloy plate ( Prior art 2: Japanese Patent Laid-Open No. 2000-077890).

[0006]

In the prior art of manufacturing shielded rooms by combining permalloy plates, and in prior art 1, there is a problem of requiring annealing treatment of permalloy after processing, and a problem of requiring a large area. ， There were problems that the shield room was heavy and there were restrictions on where to install it, and that the shield room was expensive. In the conventional technique 2, the weight of the shield room is lighter and the price can be reduced as compared with the conventional technique 1 in which a shield room is manufactured by combining permalloy plates, but the problem of requiring a large area is solved. Therefore, there has been a demand for a lighter shielded room and a lower price.

An object of the present invention is to provide a lightweight, small-sized, high-performance magnetic field shielding device at low cost by using a high-permeability sheet having a high magnetic permeability, and to detect a magnetic field generated from an inspection object, especially a living body. It is to provide a magnetic field measurement method and a magnetic field measurement device for measurement.

[0008]

A typical magnetic field measuring apparatus of the present invention comprises a magnetic field shielding apparatus for shielding a component of an external magnetic field in a direction perpendicular to the first direction, and a magnetic field shielding apparatus for generating a magnetic field generated from an inspection target. A plurality of SQs that detect a component in a direction perpendicular to the direction of 1
A cryostat that holds the UID magnetometer at a low temperature, a device that holds the cryostat, a drive detection circuit that drives the SQUID magnetometer and detects the signal from the SQUID magnetometer, and collects the output of the drive detection circuit and performs arithmetic processing. It is composed of an arithmetic processing unit and a display unit 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 magnetic permeability,
The parts are affixed to each other so as to partially overlap each other.

The innermost tubular member has 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 is formed through the plurality of tubular members in a direction perpendicular to the axis of the first direction. A component of the external magnetic field in a direction perpendicular to the first direction is shielded in a space inside the tubular member arranged on the innermost side. If the inspection target is a living body, the living body (test subject) is mounted in the space inside the innermost tubular member by making the body axis direction of the inspection target site substantially parallel to the axis of the first direction. A living-body-equipped device (bed, chair) is installed.

A part of the cryostat is inserted into the third opening, and the bottom surface of the cryostat is placed 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 portion with the smaller diameter 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 external magnetic field can be improved. The third opening is a chest surface of a living body (subject) when the inspection target is a living body, or
The bottom surface of the cryostat, which faces the back surface, is arranged in the inner space facing the chest surface of the living body or the back surface.

The positional relationship between the bottom surface of the cryostat and the surface to be inspected is adjusted by the position adjusting device, and the positional relationship is adjusted in the 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 target is mounted in the second direction perpendicular to the first direction. Further, the position adjusting device has a third direction perpendicular to the first and second directions, and a first direction,
The position of the on-board device can be changed.

Further, the magnetic field shielding device is formed with a fourth opening penetrating each tubular member in a direction perpendicular to the axis of the first direction. The opening of No. 4 is in the visual field of the subject, giving the subject a feeling of openness.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the following description, a heart of a living body will be described as a typical example of an inspection target. It is needless to say that the present invention is not limited to the heart of a living body and can be applied to, for example, the inspection of the presence or absence of a magnetic substance included in a general inspection target and the inspection of the distribution of the magnetic substance. Since the structure of the device of the present invention does not require a large area, it can be used, for example, as a device for inspecting dangerous substances including a magnetic substance,
It can also be applied to inspection of baggage at ports.

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

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

The short sides of a plurality of strips of each high magnetic permeability sheet are
The high magnetic permeability sheet is arranged substantially parallel to the axis of the first direction, and the long sides of the plurality of strips of each high magnetic permeability sheet are first on the surface (inner surface and / or outer surface) of each of the plurality of tubular members. It is attached and held so as to surround the shaft 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 the external magnetic field is improved.

The innermost tubular member has a first
Has a first opening at one end in the direction of and a second opening at the other end in the direction of
The opening is formed. A third opening is formed through the plurality of tubular members in a direction perpendicular to the axis of the first direction and into which a cryostat for keeping the plurality of SQUID magnetometers at a low temperature is inserted. A component of the external magnetic field in a direction perpendicular to the first direction is shielded in a space inside the tubular member arranged on the innermost side.

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

A more preferable shape of the cross section of the innermost tubular member perpendicular to the axis in the first direction has a diameter of about 5
It is a circle of 0 cm or more and about 200 cm or less, and should not give a feeling of pressure to the subject inserted into the innermost tubular member. In the case of a device for exclusive examination of children, the inner diameter of the cylindrical member placed further inside should be about 50 cm, and in the case of a device for examination of children and large adults, it should be closer. Also, the inner diameter of the cylindrical member disposed inside may be about 50 cm.

As a plurality of non-magnetic cylindrical members, from the viewpoint of manufacturing a magnetic field shielding device and cost, a thickness of 0.5 mm to 1
It is more preferred to use FRP hollow cylinders, aluminum hollow cylinders with mm.

In the space inside the tubular member arranged at the innermost side where the component of the extrinsic magnetic field in the direction perpendicular to the first direction is shielded, the subject can comfortably operate in any of the following three modes. Placed in a state in which the body axis direction of the body part of the subject who wants to detect the biomagnetic field is substantially parallel to the axis of the first direction. For example, a living body generated from the fetus in the chest or abdomen of the subject. The magnetic field is detected. (1) When the axis in the first direction is substantially horizontal to the floor surface, the bed on which the subject lies is placed in the innermost tubular member in a substantially horizontal state. . (2) When the axis in the first direction is substantially perpendicular to the floor surface, the subject is placed inside the tubular member arranged on the innermost side while sitting on the chair. (3) When the axis in the first direction is tilted at an angle of 20 degrees or more and 30 degrees or less with respect to the horizontal plane, the bed on which the subject lies is tilted, or the chair on which the subject sits It is placed inside the innermost tubular member with the backrest angled.

The third opening and / or the fourth opening are formed in any of the following three modes. (1) Each tubular member is provided with a hole, and the plurality of tubular members are fixed and integrated so as to concentrically surround the axis in the first direction. The hole forms a third opening. In addition to the aspect of (1), a part of each tubular member is configured to be movable, and the third and / or fourth openings are formed by moving a part of each tubular member.

That is, a part of each tubular member is movable in any one of the first direction, the circumferential direction surrounding the axis in the first direction, and the direction intersecting with the first direction. Movement of a portion of the shaped member forms the third and / or fourth opening. A specific mode is shown below. (2) Each tubular member is divided in the first direction into two parts, a first part and a second part. The respective tubular members of the first and second parts are fixed to each other so as to concentrically surround the axis in the first direction and are integrally formed. The first part is the second
Can be separated by moving in the first direction with respect to the part of.

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

The movement of the first portion relative to the second portion in the first direction causes the end of the first portion and the end of the second portion to overlap in the first direction, resulting in a first The third and / or fourth opening is formed by the second notch.

In addition to the first movement of the first part in the first direction with respect to the second part, a second movement in a direction intersecting with the first direction is also possible. The first move, or
The first movement and the second movement form an opening in the magnetic field shielding device. (3) Each tubular member is divided into two parts, a first part and a second part, in the circumferential direction surrounding the axis in the first direction. The respective tubular members of the first and second portions are fixed to each other and integrated. The first portion is configured to be movable in the circumferential direction surrounding the second portion.

Each tubular member of the first portion has a first notch portion having a semicircular portion opening on one side substantially parallel to the first direction. Each tubular member of the second portion has a second notch portion having a semicircular portion opening on one side substantially parallel to the first direction.

The movement of the first portion relative to the second portion in the circumferential direction surrounding the axis in the first direction causes the first portion and the second portion to move in the circumferential direction surrounding the axis in the first direction. Duplicate results,
The first and second cutouts form a third opening.

The first portion and the second portion are two sides that are substantially parallel to the first direction and overlap each other in the range of about 10 degrees to about 15 degrees in the circumferential direction surrounding the axis of the first direction. . Due to the movement of the first portion, approximately 90 in the circumferential direction surrounding the axis in the first direction.
An opening in the range of degrees is formed in the magnetic field shielding device.

In another configuration of the magnetic field shield device, as described in (2) and (3) above, each tubular member is the first
The second opening is formed by being divided into two parts, the first opening and the second opening, and the third opening is formed, but the third opening described above is not formed. The bottom portion of the cryostat is inserted through the first opening and the second opening. Since the fourth opening is formed at a position far from the examination target site of the subject, it does not deteriorate the magnetic field shielding rate of the external magnetic field.

The procedure of magnetic field measurement in the present invention will be described below.

First, a part of each tubular member of the magnetic field shielding device is moved in any one of the first direction, the circumferential direction surrounding the axis in the first direction, and the direction intersecting with the first direction. To form an open part.

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

Next, a part of each tubular member is opened by moving it in any one of the first direction, the circumferential direction surrounding the axis in the first direction, and the direction intersecting with the first direction. Close the department. As a result, the 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 arranged in the space inside the magnetic field shielding device and the surface of the living body is
Adjustment is made in a direction perpendicular to the first direction so that the magnetic field signal is detected significantly. The plurality of SQUID magnetometers detect the component of the magnetic field generated from the living body in the direction perpendicular to the first direction.

According to the present invention, it is possible to provide a magnetic field shielding device having a high magnetic field shielding rate of an external magnetic field, which is lightweight, small in size, low in cost and high in performance, and further, a biomagnetic field using the magnetic field shielding device can be provided. 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 compact, it is not particularly required to have a weight resistance in the place where it is installed, and it can be installed if there is a small area. ， There is no limit to the place to install the magnetic field measuring device.

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

In the magnetic field measuring apparatus of the present invention, the tangential components B _x (x, y, t) and B _y (x, y, t) of the biomagnetic field are respectively measured normal components B _z (x, y). , T) in the x direction is calculated as a value proportional to the rate of change ∂B _z (x, y, t) / ∂x, the rate of change in the y direction ∂B _z (x, y, t) / ∂y. If the constant of proportionality is 1, then the tangential component B _x (x, y,
t) and B _y (x, y, t) are given by (Equation 1) and (Equation 2).

[0041]

[Formula 1] B _x (x, y, t) = − (∂B _z (x, y, t) / ∂x) (Formula 1)

[0042]

[Number 2] _{B y (x, y, t} ) = - (∂B (x, y, t) z / ∂y) ... ( Equation 2) Next, in the x-direction rate of change in the y direction of the change rate A value S _t (x, y, t) proportional to the square root of the sum of squares is obtained. When the constant of proportionality is 1, the magnetic field waveform S _t (x, y, t) is given by (Equation 3).

[0043]

## EQU00003 ## S _t (x, y, t) = √ [{∂B _z (x, y, t) / ∂x} ² + {∂B _z (x, y, t) / ∂y} ² ] (Equation 3) S _t (x, y, t) is the magnetic field generation source inside the living body (x,
y) The magnetic field strength information projected on the plane is given. As t,
Taking the peak position of each wave of Q, R, S, S _t (x, y,
From the data of t), an isomagnetic field map connecting points (x, y) giving the same magnetic field strength is obtained by interpolation and extrapolation.

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

As the integration range, for example, when the measurement target is the heart, the period in which each of the Q, R, and S waves is generated, Q
Period of QRS wave (QRS complex) where S wave is generated from wave,
Take the period in which the T wave is generated.

[0046]

[Equation 4] I (x, y) = ∫│S _t (x, y, t) | dt (Equation 4) Furthermore, the time waveform of the magnetic field strength obtained by combining the magnetic field components in the three directions of x, y, and z. By obtaining V (x, y, t) by (Equation 5), it is possible to obtain a stable magnetic field waveform even when the movement is vigorous like a fetus.

[0047]

V (x, y, t) = √ [{∂B _z (x, y, t) / ∂x} ² + {∂B _z (x, y, t) / ∂y} ² + { B _z (x, y, t)} ² ] (Equation 5) Instead of S _t (x, y, t), V (x, y, t) is used, and the same magnetic field is obtained. It is possible to obtain a line diagram and an isointegral diagram.

The magnetic field waveforms S _t (x, y, t) and V (x, y, t) measured by each SQUID magnetometer are displayed, and the magnetic field distribution map includes an isomagnetic field diagram and an isointegral diagram. ，
Display on the display screen of the display device. It is possible to obtain data useful for diagnosis by displaying the contour lines of the magnetic field and the contour diagram in three-dimensional color by color coding according to the height of the contour lines.

[0049] That is, in a magnetic field measurement apparatus of the present invention, the tangential component _{B x (x, y, t} ), B y (x, y, t) without measuring, normal component _B z (x, y, A magnetic field distribution map in which a peak pattern appears just above the current source can be obtained from only the measurement of t). As a result, the positions of multiple current sources in the living body can be directly read, so that myocardial infarction, ischemia, arrhythmia,
Data useful for diagnosing myocardial hypertrophy and for diagnosing heart diseases such as evaluation of changes in myocardial condition before and after surgery can be obtained. The magnetic field measuring device of the present invention can measure and display data (magnetic field distribution) for diagnosing hearts of adults and fetuses in a short time of about 10 seconds to 5 minutes.

Hereinafter, a more specific example will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining a structural 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 for explaining an arrangement example of the high-permeability sheet in the hollow cylinder that constitutes the magnetic field shielding device in each embodiment of the present invention. FIG. 3 is a cross-sectional view for explaining an arrangement example of the high-permeability sheet in the hollow cylinder that constitutes the magnetic field shielding device in each embodiment of the present invention.

The flexible high-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 prior 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 each other on the long sides of the adjacent strips, and the long sides of the plurality of strips are arranged substantially in parallel. The plurality of magnetic material ribbons 25 are made of flexible resin between the holding sheets 26-1 and 26-2,
Alternatively, it is fixed by an adhesive 24. Holding sheet 26
A PET (polyethylene terephthalate) sheet is typically used as the material for -1,26-2. The size of the high magnetic permeability sheet 23 is, for example, 450 cm in length and 600 in width.
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 having an ultrafine crystal structure with a grain boundary size of 100 nm or less.

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

The magnetic field shielding device in each embodiment of the present invention is composed of a plurality of magnetic field shielding cylinders 60 arranged coaxially. Each magnetic field shielding cylinder has a high-permeability sheet supporting cylinder 80 having a different inner radius, and a high-permeability sheet layer 8 arranged on the inner peripheral surface and / or outer peripheral surface of the high-permeability sheet supporting cylinder 80.
It consists of two.

In each magnetic field shield cylinder, a circular third opening 4 for inserting the bottom surface of the cryostat inside the innermost magnetic field shield cylinder is provided corresponding to each embodiment.
3 is formed and within the field of view of the patient, which is located inside the innermost magnetic field shielding cylinder, a circular fourth opening 44
Is formed, and the patient can talk with the doctor while keeping a line of sight.

One magnetic field shielding cylinder 60 is shown in FIG. 2, 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 by using an adhesive agent or the like. The layer 82 is formed. As the high-permeability sheet supporting cylinder 80, a hollow aluminum cylinder having an inner radius r and a thickness of 0.5 mm is used.

The high permeability sheet 23 is attached by any of the following methods. (1) A plurality of high-permeability sheets 23 are attached so that they have overlapping portions. (2) The high permeability sheet 23 of the upper layer is attached so as to cover the overlapping portion of the high permeability sheet 23 of the lower layer. (3) The method of (1) and the method of (2) are combined and attached. Whichever method you use,
A plurality of high-permeability sheets 23 are laminated and attached such that the magnetic material ribbons 25 are overlapped with each other by the mutual superposition of the high-permeability sheets 23.

In each high magnetic permeability sheet 23, the long side of each magnetic material ribbon 25 is arranged so that the short side of each magnetic material ribbon 25 is substantially parallel to the central axis of the high magnetic permeability sheet supporting cylinder 80. The inside of the high permeability sheet supporting cylinder 80 is attached to the high permeability sheet supporting cylinder 80 with an adhesive or the like so as to be substantially parallel to the plane perpendicular to the center axis of the high permeability sheet supporting cylinder 80. Multiple layers of 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 Figure 3, the first
Overlapping of the high-permeability sheets 23 in each of the layers and the second layer is omitted.

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

In the following description of each embodiment, the central axes of the magnetic field shielding cylinders 60 arranged coaxially are referred to as the "central axis of the magnetic field shielding device" for simplicity. Furthermore, in the following description of each embodiment, each cylinder of the plurality of magnetic field shielding cylinders 60 is configured by being divided into two parts in the direction perpendicular to the central axis, or two parts in the circumferential direction. In the case where each of the plurality of magnetic field shielding cylinders 60 is configured by overlapping these two portions with each other, the plurality of magnetic field shielding cylinders 60 are also configured so as to be overlapped and arranged coaxially. The central axis of the magnetic field shielding cylinder is also 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 shield device 40 shown in FIG. FIG. 6 is a cross-sectional view of a plane passing through the center of the measurement visual field of the biomagnetic field measuring apparatus shown in FIG.

The biomagnetic field measuring apparatus includes a magnetic field shielding apparatus 40,
A cryostat 50 that holds a plurality of SQUID magnetometers 57 that detect a magnetic field (biomagnetic field) generated from an inspection target (living body) at a low temperature, a gantry 30-2 that supports the cryostat 50, a magnetic field shield device 40, and a gantry 3.
0-2 supporting magnetic field shield / gantry support 30-
1 and SQ via the coolant supply device or cooling device 55 for cooling the inside of the cryostat 50, the coolant supply line or cooling transmission line 54, and the data collection / sensor control line 51.
It is composed of a data collection processing / sensor control device 52 which drives and controls the UID magnetometer 57 to collect the detected biomagnetic field and performs data processing, and a single or a plurality of display devices 53 which display the result of the data processing.

Inside the cryostat 50, the liquid H supplied from the refrigerant supply device 55 via the refrigerant supply line 54.
He gas, which is cooled by e or is cooled by a compressor via a cooling transmission line 54 using a refrigerator as a cooling device 55, is supplied to a cold head arranged inside the cryostat 50 to be cooled. It

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

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

The height of the gantry 30-2 is controlled and fixed by the height control device 31 of the gantry, and the examiner (doctor) 35
Operates the gantry height control box 32 while observing the positional relationship between the inspection site of the inspection target (patient) 36 lying on the bed 20 through 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 by the signal from, and the position of the bottom surface of the cryostat 50 in the z direction is fixed. The x direction is set to the 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 processing / sensor control device 52. The FLL circuit is
The biomagnetic field signal detected by the SQUID magnetometer 57 is output. The output of the FLL circuit is filtered, amplified, converted into digital data by the AD converter, and stored in the storage device of the data collection processing / sensor control device 52. As a result of data processing by the data collection processing / sensor control device 52, for example, the magnetic field waveform S _t (x, y,
t) ((Equation 3)), V (x, y, t) (Equation 5), and the like magnetic field diagram, isometric diagram, etc. are displayed on the display screen of the display device 53.

The bed 20 on which the inspection object 36 is mounted is x
And the y-direction moving device 21, and the x- and y-direction moving device 21 is fixed to a support base 22 of the x- and y-direction moving device. The bed 20 is arranged inside the innermost magnetic field shielding cylinder of the magnetic field shielding device 40.

Incidentally, with the height of the bottom surface of the cryostat 50 fixed, it is possible to use an x, y, z direction moving device instead of the x and y direction moving device 21. In this case, the gantry 30-2 and the magnetic field shielding device 4
The gantry 3 has a positional relationship with 0 so 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 base 30-1 are integrally configured. Of course, the gantry height control device 31 and the gantry height control box 32 are unnecessary.

The examiner (doctor) 35 controls the height of the gantry while observing the positional relationship between the examination site of the examination subject (patient) 36 on the bed 20 and the bottom surface of the cryostat 50 through the fourth opening 44. Instead of the box 32, an x, y, z direction movement control box (not shown) of the bed 20 is operated. A signal from the x, y, z direction movement control box controls the x, y, z direction movement device of the bed 20, and fixes the position of the bed 20 in the x direction, y direction and z direction.

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 in a configuration in which the fourth opening 44 is not provided.

The fourth opening 44 provided in the field of view of the patient 36 gives the patient 36 a feeling of openness, and the examiner (doctor) 35 can interact with the patient 36 through the fourth opening 44, The condition of the patient can be accurately observed. The inspector (doctor) 35 can easily transmit the instruction to the patient 36. The patient 36 receives the magnetic field shielding device 4 through the fourth opening 44.
The outside of 0 can be seen, and it has the effect of reducing psychological anxiety.

As shown in FIG. 5, the central axis of the third opening 43 penetrating the magnetic field shielding cylinders and the central axis of the fourth opening 44 penetrating the magnetic field shielding cylinders are about 45 degrees. Has an angle of. As shown in FIG. 6, a SQUID magnetometer 57 is two-dimensionally arranged at the bottom of the inside of the cryostat 50, and the inside of the cryostat 50 has a refrigerant 56.
Is satisfied.

The magnetic field shield cylinder 60 is composed of a first magnetic field shield cylinder 60-1 and a second magnetic field shield cylinder 60-2. A filler 70 is filled between the first magnetic field shielding cylinder 60-1 and the second magnetic field shielding cylinder 60-2, and the first magnetic field shielding cylinder 60-1 and the second magnetic field shielding cylinder 60- The shape of No. 2 is held stably. In the example shown in FIG. 6, the filler 7
0 is filled in the lower half, but the third opening 43,
The upper half portion other than 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 blowing agent
Since it is lightweight, the first magnetic field shielding cylinder 60- can be filled even if the upper half portion except the third opening 43 and the fourth opening 44 is filled.
The shapes of the first and second magnetic field shielding cylinders 60-2 are 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 shield device shown in FIG. 7. FIG. 9 is a cross-sectional view of a plane passing through the center of the measurement visual field of the biomagnetic field measuring apparatus shown in FIG. 7, including a partially enlarged cross section.

The differences from the first embodiment will be mainly described below. The configuration of the biomagnetic field measuring apparatus of the second embodiment is the same as that of the first embodiment.
The magnetic field shielding device 40 described in 1. is divided into two in the y direction,
The first portion 40-1 of the magnetic field shielding device and the second portion 40-2 of the magnetic field shielding device are included. First of magnetic field shielding device
40-1 is the second part 40-2 of the magnetic field shielding device.
On the other hand, it is configured to be movable in the y direction. Similar to the first embodiment, the gantry 30-2 and the second portion 40-2 of the magnetic field shield device are supported by the magnetic field shield device / gantry support base 30-1.

The first portion 40-1 of the magnetic field shield device is supported and fixed to the magnetic field shield device support base 92, and the plurality of wheels 91 arranged below the magnetic field shield device support base 92 are the floor 11
It is mounted on rails 90-1 and 90-2 arranged on the surface of No. 7. The first portion 40-1 of the magnetic field shielding device 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 and the second portion 40-2 of the magnetic field shielding device can be separated.

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 easily lie on the bed 20. The patient is mounted with the foot first passing under the cryostat and eventually the chest reaching 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 separated first portion 40 of the magnetic field shielding device
-1 is moved to move the first portion 40-1 of the magnetic field shielding apparatus.
And the second portion 40-2 of the magnetic field shielding device can be overlapped in the y direction to form the third opening 43 and the fourth opening 44.

As a result, the component of the external magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device 40 is transferred to the innermost magnetic field shielding cylinder 4.
It is possible to shield with a high magnetic field shielding rate inside 0-1-1 and 40-2-1. In the space in which the external magnetic field is shielded with a high magnetic field shielding rate, the z-direction component of the biomagnetic field from the examination site can be detected with high sensitivity.

As shown in FIG. 8, the magnetic field shielding cylinder forming the first portion 40-1 of the magnetic field shielding apparatus and the magnetic field shielding cylinder constituting the second portion 40-2 of the magnetic field shielding apparatus are made to overlap with each other. It has a notch part having a part of the circumference so that the third opening 43 and the fourth opening 44 are formed when the opening is formed.

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

Inside the second magnetic field shield outer cylinder 40-2-2, the first magnetic field shield outer cylinder 40-1-2 is overlapped and arranged, and the second magnetic field shield inner cylinder 40-2-1. The first magnetic field shielding inner cylinder 40-1-1 is overlapped and arranged inside the. A third opening is shown in this overlap in FIG.

As shown in the enlarged cross section, the second magnetic field shield inner cylinder 40-2-1 and the second magnetic field shield outer cylinder 40-2.
-2, the high magnetic permeability sheet 23 forms a high magnetic permeability sheet layer 82 inside each high magnetic permeability sheet supporting cylinder 80. The high magnetic permeability sheet 23 forms a high magnetic permeability sheet layer 82 outside the high magnetic permeability sheet supporting 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, in the overlapping part,
The high-permeability sheet layer 82 is arranged close to each other to reduce the leakage flux and enhance the magnetic field shielding effect.

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

The bed 20 and the support 22 for the bed and the moving device on which the moving device 21 for the x and y directions is mounted are provided with the second magnetic field shielding inner cylinder 40-2-through the spacer 140-1.
It is arranged inside 1. For the same purpose as in Example 1, the second
Of the first magnetic field shielding inner cylinder 40-1 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. -1 and 1
The lower half between the magnetic field shielding outer cylinders 40-1-2 is filled with the filler 70-2. In the example shown in FIG. 9, the filler 7
Although 0-1 and 70-2 are filled in the lower half, it goes without saying that they may be filled in the upper half part except the third opening 43 and the fourth opening 44.

As in the first embodiment, the height of the bottom surface of the cryostat 50 is set as 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, it goes without saying that the fourth opening may be omitted, as in the first embodiment. (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 apparatus shown in FIG. 10, including a partially enlarged cross section.
FIG. 12 is a cross-sectional view for explaining the insertion / removal of the examination target (patient) into / from the biomagnetic field measuring apparatus shown in FIG.

The differences from the first embodiment will be mainly described below. The magnetic field shielding device 40 described in the first embodiment is divided into two 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. Similar to 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 base 30-1.

As shown in FIGS. 11 and 12, the first portion 40-3 of the magnetic field shield device is connected by the connecting plates 150-1 at the positive and negative y-direction ends. The magnetic field shield inner cylinder 40-3-1 and the second magnetic field shield outer cylinder 40-3-2. Similarly, the second portion 40-4 of the magnetic field shielding device of the magnetic field shielding device is coupled by the coupling plate 150-2 (not shown) at the positive and negative ends of the y direction to form the second portion 40-4. Magnetic field shielding inner cylinder 40-4-1,
It is composed of a second magnetic field shield outer cylinder 40-4-2.
As shown in FIGS. 10, 11, and 12, the first magnetic field shielding inner cylinder 40-3-1 and the second magnetic field shielding outer cylinder 40-
The 4th opening 40 which penetrates 3-2 is formed.

Inside 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 outside of 0-3-2 is covered with a transparent curved plate, respectively, and the first portion 40-3 of the magnetic field shielding device moves in the circumferential direction with respect to the second portion 40-4 of the magnetic field shielding device. At the time, I try not to get my hands or clothes caught in it.

The first portion 40-3 of the magnetic field shield is approximately 1
The second part 40 of the magnetic field shielding device having a circumference of 10 degrees
-4 has a circumference of about 270 degrees, and both ends overlap each other within 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 shield outer cylinder 40-4-2 respectively form a closed magnetic field shield device when they overlap each other at a range of about 10 degrees at both ends parallel to the central axis of the magnetic field shield device. When it is formed and overlaps in the range of about 110 degrees, it forms an open magnetic field shielding device having an opening. In the closed state, the overlapping portion is made large enough 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. The second magnetic field shield outer cylinder 40-4 is arranged.
-2, a T-shaped elongated groove for receiving the guide 105-2 is formed on the inner peripheral surface of the high magnetic permeability sheet supporting cylinder 80.

Similarly, the first magnetic field shielding inner cylinder 40-3
On the outer peripheral surface of the high-permeability sheet supporting cylinder of No. -1, a T-shaped elongated plate is arranged as a guide 105-1, and the high magnetic permeability of the second magnetic field shielding inner cylinder 40-4-1 is provided. 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 supporting cylinder.

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

As shown in FIG. 11, the first magnetic field shielding device is
Of the magnetic field shielding cylinder constituting the 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 so as to form the third opening 43 when overlapped,
It has a notch with a part of the circumference.

FIG. 12A shows a state in which the patient 36 lies on the bed 20 and the biomagnetic field from the examination site is measured. The magnetic field shielding cylinder that constitutes the first portion 40-3 of the magnetic field shielding device and the magnetic field shielding cylinder that constitutes the second portion 40-4 of the magnetic field shielding device overlap each other. The positional relationship between the first portion 40-3 and the second portion 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 inside the innermost magnetic field shielding cylinders 40-3-1 and 40-4-1 with a high magnetic field shielding rate. In the space in which the external magnetic field is shielded with a high magnetic field shielding rate, the z-direction component 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 shield device is rotated manually or automatically by using a handle (not shown) attached to the first portion 40-3. Direction is moved, the position of the first portion 40-3 is locked, an opening is formed, and an open space is formed in an angular range of about 90 degrees. As a result, in the open space, the doctor 35 can move 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 as 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, it goes without saying that the fourth opening may be omitted, as in the first embodiment. (Embodiment 4) A biomagnetic field measuring apparatus according to Embodiment 4 of the present invention is
A part of the configuration of the biomagnetic field measuring apparatus of Example 3 was changed,
It is a bedside biomagnetic field measuring 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 base 30-1, and a plurality of wheels 100 are also movably mounted on the support base 22 of the bed and the moving device. Individual wheels 29-1, 29-2, 29-
3, 29-4 (not shown) are arranged. The data collection processing / sensor control device 52, the display device 53, the refrigerant supply device or the cooling device 5 is mounted on a trolley having a plurality of 100-1.
5 is installed.

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

As shown in FIG. 12C, the wheels 29'-
1, 29'-2, 29'-3 (not shown), 29'-4
After moving the bedside biomagnetic field measuring apparatus to the vicinity of the bed moving table 103, which has a unit (not shown), as shown in FIG. 12B, the first portion 40 of the magnetic field shielding apparatus is shown. -3 is moved in the circumferential direction to lock its position, and an open space is formed within an angle range of about 90 degrees.

The x, y, z direction moving device 21 'of the bed 20 and the bed 20-1, x, y, z direction moving device 21' of the bed moving table 10 of the bedside biomagnetic field measuring apparatus.
Using and, bed 2 in each of the x, y, and z directions
0 and bed 20-1 position to adjust 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, the biomagnetic field from the examination site of the patient 36 is measured in the state shown in FIG. After the measurement of the biomagnetic field is completed, in the state shown in FIG.
The bed 20 in the x, y and z directions is used by using the y and z direction moving device 21 'and the bed 20-1, x, y and z direction moving device 21' of the bed moving table 10. Also, 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 bedside biomagnetic field measuring apparatus according to the fourth embodiment can be freely moved, and can be moved in a hospital to perform an inpatient bedside examination. Therefore, the emergency patient,
When measuring a bedridden patient, the patient does not have to move to the examination room where the biomagnetic field measuring device is installed,
The burden on the patient is reduced. (Embodiment 5) FIG. 13 is an embodiment of Embodiment 5 of the present invention, in which a medical examination vehicle equipped with the biomagnetic field measuring apparatus described in Embodiment 3 or 4 in an automobile (movable biomagnetic field measuring apparatus).
FIG. 6 is a perspective view showing an example of FIG. The entire biomagnetic field measuring apparatus is a vibration isolation table 11 placed on a floor 110 inside the vehicle.
It is placed and fixed on top of the 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 examination car is used for regular group medical examinations by moving to local communities such as schools and public health centers. (Sixth Embodiment) FIG. 14 is a perspective view showing a configuration example of a magnetic field shielding apparatus used in a biomagnetic field measuring apparatus of a sixth embodiment of the present invention, including a partial enlargement. FIG. 15 is a cross-sectional view taken along a plane passing through the center of the measurement visual field of the biomagnetic field measuring apparatus using the magnetic field shielding apparatus shown in FIG.

The magnetic field shielding apparatus shown in FIG. 14 is obtained by dividing the magnetic field shielding apparatus 40 described in the first embodiment into two in the circumferential direction to form a first portion 40-5 of the magnetic field shielding apparatus and a second portion of the magnetic field shielding apparatus. It is composed of a 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 portions 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 wheel 118 is arranged inside the movement guide groove 119 formed in the floor 117. Second magnetic field shield inner cylinder 40-6-1, second magnetic field shield outer cylinder 40-6-
The upper parts of 2 are connected by a connecting plate 115. An upper coupling portion 116 for movement is fixed to the coupling plate 115 for coupling with a circular guide rail arranged on the ceiling.

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

As shown in FIG. 15, the first magnetic field shield inner cylinder 40-5-1 is formed by the magnetic field shield cylinder support 128.
The second magnetic field shield outer cylinder 40-5-2 is fixed to the floor 117 by the magnetic field shield cylinder support 120, respectively. S
The cryostat 50-1 on the side where the QUID magnetometer 57 is 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 the side where the SQUID magnetometer 57 is arranged, 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 portion 40-6 of the magnetic field shielding device is made higher than the height of the first portion 40-5 of the magnetic field shielding device so that the second portion 40-6 of the magnetic field shielding device is made higher. Simplify the structure for rotating. The second portion 40-6 of the magnetic field shielding device has a circumference of about 200 degrees, and the first portion 40-5 of the magnetic field shielding device has a circumference of 180 degrees, and the first portion 40-5 of the magnetic field shielding device has a circumference of about 180 degrees. The configuration is such that it overlaps within a range of 10 degrees. That is, the first magnetic field shield inner cylinder 40-5-1 and the second magnetic field shield inner cylinder 40-5-1
Magnetic field shield inner cylinder 40-6-1, and second magnetic field shield outer cylinder 40-5-2 and second magnetic field shield outer cylinder 40.
-6-2 forms a closed magnetic field shielding device when overlapping at approximately 10 degrees at both ends parallel to the central axis of the magnetic field shielding device, and when overlapping at approximately 180 degrees, A magnetic field shielding device in an open state 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 transferred to the innermost magnetic field shielding cylinder 40.
It is possible to shield with a high magnetic field shielding rate inside -5-1 and 40-6-1. In the space where the external magnetic field is shielded with a high magnetic field shielding rate, the x-direction component of the biomagnetic field from the examination site can be detected with high sensitivity.

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

The central axes of the magnetic field shielding cylinders 60 constituting the magnetic field shielding apparatus used in the sixth embodiment are 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 apparatus used in the sixth embodiment, the patient 36 can easily enter the inside of the magnetic field shielding apparatus, and the examination site can be efficiently aligned. The magnetic field shield device used in the sixth embodiment is small, and the installation area of the biomagnetic field measuring device can be small.

With the height of the cryostat 50-1 fixed, instead of the x- and y-direction moving device, the x, y, z-direction control of the chair 122 on which the inspection object 36 is seated is controlled. , Z direction moving device, SQ
The cryostat 5 on the side where the UID magnetometer 57 is arranged
It goes without saying that the 0-1 surface and the surface of the inspection site of the inspection object 36 can be aligned. (Embodiment 7) FIG. 16 shows Embodiment 7 of the present invention.
4 is a cross-sectional view taken along a plane passing through the center of the measurement visual field of the biomagnetic field measuring apparatus using the magnetic field shielding apparatus shown in FIG. 15. In the biomagnetic field measuring apparatus according to the seventh embodiment, the magnetic field shielding apparatus shown in FIGS. 14 and 15 is arranged on the floor 117-1 that is inclined with respect to the floor 117 by 20 degrees or more and 30 degrees or less. Other configurations are the same as those in the sixth embodiment. (Embodiment 8) FIG. 17 is a perspective view showing a structural example of a biomagnetic field measuring apparatus according to Embodiment 8 of the present invention. FIG. 18 is a cross-sectional view of a plane passing through the center of the measurement visual field of the biomagnetic field measuring apparatus shown in FIG.

The differences from the first embodiment will be mainly described below. The magnetic field shield device 40-7 includes a magnetic field shield inner cylinder 40-
7-1, composed of a magnetic field shielding outer cylinder 40-7-2,
The magnetic field shield device 40-7 is held by the magnetic field shield device support 130 fixed to the floor 117.

In the eighth embodiment, since the flat type SQUID magnetometer in which the detection coil for detecting the magnetic field is a thin film is used, a small cryostat can be used. Example 8
Then, in the configuration of the magnetic field shielding device 40 described in the first embodiment,
The cryostat 50-2 in which the SQUID magnetometer is two-dimensionally arranged at the bottom without forming the third opening 43 into which the cryostat 50 is inserted is attached to the magnetic field shielding inner cylinder 40-7-.
Place inside 1. The cryostat 50-2 is held by the cryostat holding plate 132, and the cryostat holding plate 132 is held by the fixing base 131 of the cryostat holding plate fixed to the floor 117.

The bed 20 and the support 22 of the bed and the moving device for mounting the moving device 21 in the x and y directions are arranged 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 upper half may be filled.

In the eighth embodiment, since the third opening described in the first embodiment is not formed, the component of the external magnetic field in the direction perpendicular to the central axis of the magnetic field shielding device 40 is transferred to the innermost magnetic field shielding cylinder 4.
It is possible to shield the inside of 0-7-1 with a higher magnetic field shielding rate than the magnetic field shielding apparatus shown in the first embodiment. In the space in which the external magnetic field is shielded with a higher magnetic field shielding rate, the z-direction component of the biomagnetic field from the examination site can be detected with high sensitivity.

The patient placed on the bed 20 is allowed to pass through the second opening 42 into the inside of the magnetic field shielding inner cylinder 40-7-1, and more preferably, the foot first passes through the lower portion of the cryostat 50-2. Then, the chest is inserted so that the chest reaches the lower part of the cryostat and the feeling of pressure is reduced as much as possible. Of course, as shown in FIG. 18, the magnetic field shielding inner cylinder 40-7-
You may carry in in 1. The doctor determines 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. To do.

Similar to the first embodiment, with the height of the cryostat 50-2 being a fixed position, the x, y, z direction moving device of the bed 20 can be used instead of the x, y direction moving device 21. Needless to say. Further, it goes without saying that the fourth opening may be omitted, as in the first embodiment. (Ninth Embodiment) FIG. 19 is a diagram showing an example of a magnetic field waveform measured by the biomagnetic field measuring apparatus according to the first embodiment of the present invention. FIG. 19 shows a magnetic field generated from the heart of a healthy subject, which is detected by using a total of 4 channels of SQUID magnetometers arranged at each vertex of a square at the bottom of the inside of the cryostat, and shows a magnetic field waveform of 1 channel. The horizontal axis of FIG. 19 is time (sec), and the vertical axis is the differential value of the detected magnetic field (pT /
m) is shown.

The structure of the magnetic field shielding apparatus 40 used when obtaining the measurement results of Example 8 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 has a high magnetic permeability outside the high magnetic permeability sheet supporting cylinder 80. Sheet 2
3 to form a high magnetic permeability sheet layer 82. The magnetic field shielding device used does not have the fourth opening. The third opening has a radius of 30 due to the insertion of a cryostat with a circular cross section in which the 4-channel SQUID magnetometer is placed.
It was a circle of cm.

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

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

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

As shown in FIG. 2, the flexible high-permeability sheet 23 has the magnetic material ribbons 25 so that the short sides of the magnetic material ribbons 25 are substantially parallel to the central axes of the hollow cylinders.
Adhesive is attached to the peripheral surface of each hollow cylinder with an adhesive so that the long side of the hollow cylinder surrounds the center axis of each hollow cylinder and is almost parallel to the plane perpendicular to the center axis of each hollow cylinder. Multiple layers of magnetic susceptibility sheet 23 were formed.

By using the magnetic field shield having a simple structure, the component in the direction perpendicular to the central axis of the magnetic field shield for the external magnetic field (the central axis of the first, second and third magnetic field shield cylinders) is minimized. At the position of the central axis of the first magnetic field shielding cylinder inside,
It could be attenuated 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 z-direction component of the biomagnetic field generated from the inspection 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 central axis of the magnetic field shielding device, and the magnetic field generated from the heart of an adult healthy person had an SN ratio of 1 at the time when the R wave was emitted.
It turned out that it can be measured at 0 or more.

The high magnetic permeability sheet 23 is attached to the peripheral surface of each hollow cylinder so that the long side of the magnetic material ribbon 25 is parallel to the central axis of each hollow cylinder. When each magnetic field shielding cylinder is formed by forming the 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 is about − at the position of the central axis of the innermost first magnetic field shielding cylinder. Three
It could be attenuated to 1 dB.

In the configurations of the first embodiment, the second embodiment, the third embodiment, the fourth embodiment, the fifth embodiment, and the eighth embodiment described above,
When the fourth opening is provided, the diameter of the fourth opening can be about 30 cm when the inner diameter of the innermost magnetic field shielding cylinder is about 1 m.

In addition, in the configurations of the first, second, and eighth embodiments, when the examination subject (patient) is carried into the inner space of the innermost magnetic field shielding cylinder of the magnetic field shielding device, the foot portion is first. First, pass the lower part of the cryostat so that the chest finally reaches the lower part of the cryostat to minimize the feeling of pressure.

[0130]

According to the present invention, it is possible to realize a magnetic field shielding device having a high magnetic field shielding rate, which is lightweight, small in size, low in cost and high in performance, by using a high magnetic permeability sheet having a high magnetic permeability. Since the magnetic field shielding device of the present invention is lightweight and small, it is not particularly required to have a load resistance in the place where it is installed, and it can be installed if there is a small area. The magnetic field shielding device, that is, the magnetic field measuring device is installed. There are no restrictions on places.

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

[Brief description of drawings]

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

FIG. 2 is a perspective view illustrating an arrangement example of a high-permeability sheet in a hollow cylinder that constitutes a magnetic field shielding device according to each embodiment of the present invention.

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

FIG. 4 is a perspective view showing a configuration example of the 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.

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

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

8 is a perspective view of the magnetic field shield device shown in FIG.

9 is a cross-sectional view of a plane passing through the center of the measurement visual field of the biomagnetic field measuring apparatus shown in FIG.

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

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

FIG. 12 is a cross-sectional view illustrating the insertion / removal of an inspection target (patient) into / from the biomagnetic field measuring apparatus shown in FIG.

FIG. 13 is an example of Example 5 of the present invention, and Example 3
Alternatively, a perspective view including a partially broken portion showing an example of a medical examination vehicle in which the biomagnetic field measuring apparatus of the fourth embodiment is mounted on an automobile.

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

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

16 is Embodiment 7 of the present invention and is a cross-sectional view taken along a plane passing through the center of the measurement visual field of the biomagnetic field measuring apparatus using the magnetic field shielding apparatus shown in FIG.

FIG. 17 is a perspective view showing a configuration example of a biomagnetic field measuring apparatus of Example 8 of the present invention.

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

FIG. 19 is a diagram showing 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
Directional 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 ... Wheel,
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 ... Inspector (doctor),
36 ... Examination target (patient), 40 ... Magnetic field shielding device, 40-
DESCRIPTION OF SYMBOLS 1 ... 1st part of a magnetic field shielding apparatus, 40-1-1 ... 1st magnetic field shielding inner cylinder, 40-1-2 ... 1st magnetic field shielding outer cylinder, 40-2 ... 2nd of magnetic field shielding apparatus Part, 40-2
-1 ... 2nd magnetic field shield inner cylinder, 40-2-2 ... 2nd magnetic field shield outer cylinder, 40-3 ... 1st part of magnetic field shield apparatus, 40-3-1 ... 1st magnetic field shield inner side Cylinder, 40-3
-2 ... 2nd magnetic field shielding outer cylinder, 40-4 ... 2nd part of magnetic field shielding apparatus, 40-4-1 ... 2nd magnetic field shielding inner cylinder, 40-4-2 ... 2nd magnetic field shielding outer side Cylinder, 40-5
... 1st part of magnetic field shielding device, 40-5-1 ... 1st magnetic field shielding inner cylinder, 40-5-2 ... 2nd magnetic field shielding outer cylinder, 40-6 ... 2nd part of magnetic field shielding device , 40-6-
1 ... 2nd magnetic field shielding inner cylinder, 40-6-2 ... 2nd magnetic field shielding outer cylinder, 40-7 ... magnetic field shielding apparatus, 40-7-
1 ... Magnetic field shielding inner cylinder, 40-7-2 ... Magnetic field shielding outer cylinder, 41 ... First opening, 42 ... Second opening, 43 ... Third
Opening, 44 ... Fourth opening, 50, 50-1, 50-2
... cryostat, 51 ... data collection / sensor control line, 52 ... data collection processing / 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-permeability sheet supporting cylinder, 82 ... High-permeability sheet layer, 90-1, 90
-2 ... Rail, 91 ... Wheel, 92 ... Magnetic field shielding device support stand, 100, 100-1 ... Wheel, 101 ... Coupling part, 10
3 ... Bed moving table, 105 ... Guide, 110 ... Floor in vehicle, 111 ... Vibration isolation table, 112 ... Anchor, 115 ... Coupling plate, 116 ... Upper coupling part for moving, 117 ... Floor, 1
17-1 ... Inclined floor, 118 ... Wheels, 119 ... Movement 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 base, 132 ... Cryostat holding plate, 140-1, 140-2 ... Spacer,
150-1, 150-2 ... Coupling plate.

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Akihiko Kamtori 1-280 Higashi Koikeku, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Keiji Tsukada 1-280 Higashi Koikeku, Kokubunji, Tokyo Hitachi Ltd. Central Research Laboratory (72) Inventor Koichi Yokozawa 1-280, Higashi Koikekubo, Kokubunji City, Tokyo Central Research Laboratory, Hitachi, Ltd. (56) Reference JP-A-9-214166 (JP, A) JP-A-2000-77890 (JP, A) JP 10-41670 (JP, A) JP 2000-254108 (JP, A) JP 3-126439 (JP, A) JP 7-59743 (JP, A) JP 6- 90916 (JP, A) JP 7-147497 (JP, A) JP 63-292698 (JP, A) Actually open 3-73104 (JP, U) Actually open 53-112468 (JP, U) ( 58) Fields investigated (Int.Cl. ⁷ , DB name) A61B 5/05 G01R 33/035 H05K 9/00

Claims (9)

(57) [Claims] 1. A plurality of non-magnetic cylinders having a hollow portion, in which a part of a plurality of high permeability sheets having a high magnetic permeability are overlapped with each other, concentrically surrounding an axis in a first direction. The tubular member that includes a member and is arranged 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 the first opening. Has a third opening penetrating the plurality of tubular members in a direction perpendicular to the axis of the direction, and is located in the innermost space of the tubular member and is arranged in the first direction of the external magnetic field. A magnetic field shielding device that shields a component in a vertical direction; a living body mounting device that holds a living body in a body axis direction substantially parallel to the axis of the first direction and is placed in the inner space; A cryous that is inserted into an opening and has its bottom placed in the inner space to keep a plurality of SQUID magnetometers at a low temperature. And each tubular member is divided in the first direction into two parts, a first part and a second part, the first part relative to the second part. Is movable in the first direction to be separable, and each of the tubular members of the first portion has a first notch portion having a semicircular portion opening at an end, Each of the tubular members of the second portion has a second notch having a semi-circular portion open at the end, and the first direction of the first portion with respect to the second portion. Movement, the third opening is formed by the first cutout portion and the second cutout portion, and the plurality of SQUID magnetometers are arranged in the first direction of the magnetic field generated from the living body. A magnetic field measuring device characterized by detecting a component in a direction perpendicular to. 2. The magnetic field measuring device according to claim 1, wherein:
A magnetic field measuring apparatus, wherein a cross-sectional shape of each of the plurality of tubular members perpendicular to an axis in the first direction is a circle. 3. The magnetic field measuring device according to claim 1, wherein:
The magnetic field measuring apparatus, wherein the number of the tubular members is in the range of 2 to 5. 4. The magnetic field measuring device according to claim 1, wherein:
The cross-sectional shape of the innermost tubular member perpendicular to the axis in the first direction is a circle, and the diameter of the circle is about 50.
A magnetic field measuring device characterized in that it is not less than cm and not more than about 200 cm . 5. The magnetic field measuring device according to claim 1,
The high-permeability sheet is formed in a strip shape by sandwiching a magnetic material having a high magnetic permeability between non-magnetic holding sheets, and the plurality of strips overlap each other on the long sides of the adjacent strips. 2. The magnetic field measuring device, wherein the long sides of the strips are arranged substantially parallel to each other. 6. The magnetic field measuring device according to claim 1, wherein:
The high-permeability sheet is formed in a strip shape by sandwiching a magnetic material having a high magnetic permeability between non-magnetic holding sheets, and the plurality of strips overlap each other on the long sides of the adjacent strips. The long sides of the strips are arranged substantially parallel to each other, and the short sides of the plurality of strips of each of the high permeability sheets are arranged substantially parallel to the axis in the first direction, and the high permeability sheets are The magnetic field measuring device, wherein the long sides of the plurality of strips of each high-permeability sheet are held on the surface of each tubular member so as to surround the axis in the first direction inside. 7. The magnetic field measuring device according to claim 1, wherein:
The magnetic field measuring apparatus, wherein the axis in the first direction is substantially horizontal. 8. The magnetic field measuring device according to claim 1,
The magnetic field measuring device, wherein the diameter of the third opening is smaller than the diameter of the bottom surface of the cryostat. 9. A plurality of non-magnetic cylindrical members having hollow portions, wherein a plurality of high magnetic permeability sheets having a high magnetic permeability are partially overlapped with each other, concentrically surrounding an axis in the first direction. And the innermost cylindrical member has a first opening at one end in the first direction, a second opening at the other end in the first direction, and a second opening at the other end in the first direction. A third opening, which penetrates the plurality of cylindrical members in a direction perpendicular to the axis and into which a cryostat for holding the plurality of SQUID magnetometers at low temperature is inserted, is provided on the inner side of the innermost cylindrical member. A magnetic field shielding device that shields a component of an external magnetic field in a direction perpendicular to the first direction in a space, and a body axis direction substantially parallel to the axis of the first direction to hold a living body in the inner space. The living body mounting device to be arranged, and the bottom surface inserted into the third opening is the inside It is arranged in the space, a plurality of SQUID
It is equipped with a cryostat that keeps the magnetometer at a low temperature,
In the circumferential direction in which each of the cylindrical members surrounds the first direction,
Part and a second part, the first part is movable in the circumferential direction with respect to the second part, and each cylindrical member of the first part is Each of the cylindrical members of the second portion has a first notch portion having a semicircular portion that is open on one side parallel to the first direction, and each cylindrical member of the second portion is parallel to the first direction. A second notch portion having a semicircular portion opening to a side is provided, and the first notch portion and the first notch portion are moved by the movement of the first portion with respect to the second portion in the circumferential direction. The second cutout portion forms the third opening, and the plurality of SQUID magnetometers detect a component of a magnetic field generated from the living body in a direction perpendicular to the first direction. Magnetic field measuring device.