JPH06327645A - Measuring apparatus for magnetism of living body - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a biomagnetism measuring device for estimating the position of an active region in a living body, and provides a biomagnetism measuring device improved so as to eliminate the influence of a volume current and improve the accuracy. The purpose is to do. In a biomagnetism measuring device for estimating a magnetic field generated by an electric phenomenon occurring in a living body by a plurality of pickup coils to estimate a position where the electric phenomenon is occurring, a mechanism for changing an installation angle of the pickup coil with respect to the living body is provided. Prepare

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biomagnetism measuring device for estimating the position of an active area in a living body.

[0002]

2. Description of the Related Art Electric phenomena occurring in a living body simultaneously generate a weak magnetic field. Therefore, by measuring the magnetic field distribution and inversely estimating the active region in the living body, it can be useful for estimation and diagnosis of a diseased part.

In the conventional biomagnetism measuring device, in order to measure the magnetic field generated from the current source in the brain, FIG.
As shown in FIG. 3, a plurality of pickup coils 1 are installed on a curved surface at equal intervals in the vertical direction so as to face the center of the curved surface to pick up the magnetic field.

Further, in order to measure the magnetic field generated from the current source in the heart, a plurality of pickups are horizontally arranged at equal intervals to pick up the magnetic field, as shown in FIG. 6 (B).

[0005]

However, the human head is not a perfect sphere, and the magnetic field due to the volume current flowing at the boundary of the head is measured simultaneously with the magnetic field directly generated by the current source. Therefore, the position of a current dipole with a depth of several cm necessary for medical diagnosis can be estimated by several meters from the magnetic field generated from the deep part of the heart or brain by measuring the magnetic field by volume current.
A large error was involved in making the precision of m.

An object of the present invention is to provide an improved biomagnetism measuring device which eliminates the influence of the volume current to eliminate the error in the estimated position and improves the accuracy.

[0007]

Means adopted by the present invention for solving the above-mentioned problems will be described. A biomagnetism measuring device for estimating a position where an electric phenomenon is occurring by picking up a magnetic field generated by an electric phenomenon occurring in a living body with a plurality of pickup coils, and including a mechanism for changing an installation angle of the pickup coil with respect to the living body.

[0008]

In the mechanism for changing the installation angle of the pickup coil, one end of the coil support that supports the pickup coil is a rotating sphere, and the rotating sphere is rotatable on the lower support base that supports the coil support close to the living body surface. A depression is provided, and a rotary sphere is fitted into this rotation depression and fixed at an angle such that the center of the axis of the pickup coil is perpendicular to the living body surface.

As described above, since the installation angle changing mechanism fixes the pickup coil at an angle such that the center of the axis of the pickup coil is perpendicular to the living body surface, the influence of the volume current disappears and the estimated position is eliminated. The accuracy of can be improved.

[0010]

EXAMPLE An example of the present invention will be described. FIG. 5 is a block diagram of a biomagnetism measuring device. The coil array 14 in which a plurality of pickup coils are installed is stored in the dewar 16, and the connecting wire from each pickup coil is a connecting terminal 19
It is taken out through.

SQUID (Superconducting QUantum In)
The control unit 20 supplies a bias current necessary for the operation of the SQUID to the coil array 14, converts the output signal from the coil array 14 into a digital value, and outputs the digital value to the data processing unit 21.

Reference numeral 22 is a tomographic image acquisition unit, which acquires a tomographic image of the surface of the living body to be measured by, for example, MRI or the like and inputs it to the data processing unit 21. Reference numeral 23 is an image display unit. As shown in FIG. 4, the coil array 14 is stored in the dewar 16 so that the coil array 14 can be taken out from the dewar 16, and liquid helium is injected from the injection port 18 during measurement, so that the coil array is removed. Cooling.

Further, the insulator 17 acts as a heat insulating material for reducing evaporation of liquid helium. In addition, an airbag 15 is provided between the dewar 16 and the human body.
Is inserted to keep the distance between the human body and Dewar constant.

Next, the structure of the coil array 14 in which a plurality of pickup coils are installed will be described with reference to FIG. In FIG. 1, 1 is a pickup coil for picking up a magnetic field, and 2 is a coil support for supporting the pickup coil 1.

One end of the coil support 2 on the human body side is a rotating sphere 4, and a lower support base 3 for supporting the coil support 2 is provided with a rotating recess 5 in which the rotating sphere 4 is rotatable. The rotary sphere 4 is inserted into the. The other end of the coil support 2 passes through the rotation port 17 of the upper support base 6 and the scale plate 8 and is fixed with a fastener 9.

As shown in FIG. 2A, the rotary sphere 4 and the rotary dent 5 are housed so that the slider 10 can be moved by a stopper 11 in order to prevent the rotary sphere 4 from coming out of the rotary dent 5. To do. Since the diameter of the slider 10 is smaller than the diameter of the rotating sphere 4, even if the angle of the coil support 2 is changed, the rotating sphere 4 is not pulled out from the rotating recess 5.

As another specific example, as shown in FIG. 2 (B), after the rotary sphere 4 is fitted into the rotary recess 5, a stopper 12 is attached to prevent the rotary sphere 4 from being pulled out. You can also On the other hand, the other end of the coil support 2 can be moved within the range of the rotation port 7 provided in the upper support base 6, and the other end is moved to change the angle of the axis of the pickup coil 1.

To change the axial angle of the coil, as shown in FIG. 3, when the pointer of the scale plate 8 is aligned with 0 of the scale 13 graduated on the upper support base 6, the coil axis is changed to the lower support base 3. It is perpendicular to the curved surface, and when changing the axis of the coil, the pointer of the scale plate 8 is aligned with the scale of the angle to be changed, and tightened with the fastener 9 to fix.

Next, the operation of the embodiment will be described. First, three-dimensional image data of a human head is acquired from the tomographic image acquisition unit 22 and input to the data processing unit 21. The data processing unit 21 extracts the boundary of the head surface from the fetched three-dimensional image data and smooths the boundary surface so as to facilitate the retrieval of the vertical plane.

Next, based on the coordinates of the rotation axes of the pickup coils that have been incorporated in advance, the axes of the pickup coils that are perpendicular to the head surface are compared with the boundary of the head surface. Find the angle. The axial angle of each coil is set to the angle calculated by and stored in the dewar, the dewar is placed on the head of the subject's head, and the measurement of the brain magnetic field is started.

Since each coil is set so that the axis of each coil is perpendicular to the head surface, the magnetic field generated by the volume current does not intersect with the coil, and only the brain magnetic field is measured. The data processing unit 21 calculates the position of the magnetic field generation source in the brain, that is, the position of the current source, based on the current value picked up by each pickup coil.

The calculated position of the current source is superimposed on the head image input from the tomographic image acquisition unit 22, and the image display unit 2 is displayed.
Display in 3. Although the magnetic measurement of the head has been described in the embodiment, the same applies to the case of the heart, and in this case, the lower support base 3 and the upper support base 6 are shaped to match the shape of the human body. used.

[0023]

As described above, according to the present invention, the following effects can be obtained. The installation angle changing mechanism fixes the pickup coil at an angle such that the axis center of the pickup coil is perpendicular to the living body surface, so that the influence of the volume current is eliminated and the accuracy of the estimated position can be improved. .

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a specific example of coil fixing of the embodiment.

FIG. 3 is a specific example of coil fixing of the embodiment.

FIG. 4 is an explanatory diagram of a storage state of a coil array.

FIG. 5 is a configuration diagram of a biomagnetism measuring device.

FIG. 6 is a configuration diagram of a conventional pickup coil array.

[Explanation of symbols]

 1 Pickup coil 2 Coil support 3 Lower support base 4 Rotating sphere 5 Rotating dent 6 Upper support base 7 Rotating opening 8 Scale plate 9 Fastener 10 Slider 11 Stopper 12 Stopper 13 Scale 14 Coil array 15 Airbag 20 SQUID control part 21 Data processing unit 22 Tomographic image acquisition unit 23 Image display unit

Claims (2)

[Claims] 1. A biomagnetism measuring apparatus for estimating a position where an electric phenomenon occurs by picking up a magnetic field generated by an electric phenomenon generated in a living body with a plurality of pickup coils, and changing an installation angle of the pickup coil with respect to the living body. A biomagnetism measuring device having a mechanism. 2. The installation angle changing mechanism, wherein one end of a coil support that supports the pickup coil is a rotating sphere, and the rotating sphere rotates on a lower support base that supports the coil support near a living body surface. It has a possible rotary depression,
The biomagnetism measuring device according to claim 1, wherein a rotary sphere of the pickup coil is fitted into the rotary recess to change an installation angle.