JP4630194B2 - Biological measuring device and biological measuring method - Google Patents

Description

  The present invention relates to a technique for measuring a magnetic field generated from a human body, and mainly relates to a technique for measuring a magnetic field generated along with neural activity of a brain.

MEG (Magnetoencephalography), generally called “magnetoencephalograph”, can measure a weak magnetic field generated by the nerve activity of the brain from the scalp by a superconducting quantum interference device (SQUID). MEG is excellent in measurement accuracy, and is expected as a tool for elucidating higher-order brain functions such as perception, emotion, learning, and language.
JP 2004-160085 A

  However, MEG is not good at accurately identifying from which part of the brain the magnetic field is generated. On the other hand, MRI (Magnetic Resonance Imaging) has a function of imaging the inside of the brain based on the principle of magnetic resonance. Therefore, if magnetic field distribution data indicating the intensity distribution of the magnetic field generated from the brain is acquired by MEG and superimposed on the brain image obtained by MRI, how much magnetic field is generated from which part of the brain. It becomes easier to identify visually. This alignment is usually performed by the following method.

1. A marker containing moisture (hereinafter referred to as “first marker”) such as a vitamin E tablet is attached to a predetermined position of the subject's head. In this state, the inside of the brain is imaged by MRI. At this time, since the MRI detects moisture in the first marker, the first marker is projected in the MRI image.
2. Next, another type of marker (hereinafter referred to as “second marker”) that generates a magnetic field by an electromagnetic coil is attached to the same position on the subject's head (when the first marker and the second marker are collectively referred to as Simply called "marker"). In this state, magnetic field distribution data is acquired by the MEG. At this time, since the MEG also detects the magnetic field generated by the second marker, the magnetic field generated by the second marker is projected in the magnetic field distribution data.
3. If the magnetic field distribution data is superimposed on the MRI image so that the position of the second marker appearing in the magnetic field distribution data matches the position of the first marker appearing in the MRI image, the magnetic field generated from the brain The positional relationship between the intensity distribution and the brain region can be specified. In other words, the position of the marker is a reference point for superimposing the magnetic field distribution data and the MRI image.

  In order to correctly superimpose the magnetic field distribution data and the MRI image, the second marker must be attached at the same position as the first marker. Usually, a plurality of first markers and a plurality of second markers are each attached to the head, and their attachment positions are set to positions that are somewhat scattered on the head. Typically, a total of five markers are arranged, three on the forehead and one on each of the left and right depressions (hereinafter simply referred to as “recesses”) that are generated when the mouth is opened. The present inventor has recognized the difficulty of matching the positions of the two types of markers as a problem and has come up with means for solving this problem.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a technique for accurately specifying a generation site when measuring a magnetic field generated from a human body.

One embodiment of the present invention is an apparatus for measuring an internal state of a human body.
This apparatus uses two types of markers, a first marker and a second marker. This device images the inside of the human body with the first marker attached, acquires a first captured image on which the first marker is projected, and images the outside of the human body with the first marker attached in the same manner. Then, a second captured image indicating the attachment position of the first marker is acquired. Next, with reference to the second captured image, the position on the human body where the first marker was attached is irradiated, and the second marker that generates a magnetic field by itself is attached according to the irradiation position. Measure the strength of the magnetic field generated from the inside.

  By irradiating the position where the first marker was attached with reference to the second captured image after the first marker is removed, it becomes easier to attach the second marker at the same position as the first marker.

  According to the present invention, when a magnetic field generated from a human body is measured, it becomes easy to accurately specify the generation site.

FIG. 1 is a schematic diagram for explaining the basic principle of MEG.
There are hundreds of millions of nerve cells in the brain, and the brain processes information by the excitement of nerve cells. When the potential from the axon 30 toward the synaptic gap 32 and the cell body 34 changes with nerve excitation, magnetic field lines 38 are generated. A part of the magnetic field lines 38 penetrates the head surface 36 and appears outside the head. The living body measuring apparatus 100 having a function as an MEG is an apparatus for detecting nerve lines in the brain by detecting the lines of magnetic force 38.

  The biological measurement device 100 places a plurality of sensor devices 40 outside the head surface 36. The sensor device 40 detects lines of magnetic force 38 generated from each part of the brain. The sensor device 40 includes a magnetic flux detection coil 42 and a SQUID 44. The magnetic flux detection coil 42 guides the magnetic field generated from the brain to the SQUID 44 while eliminating the influence of an external magnetic field. The SQUID 44 detects the strength of this magnetic field. The biological measurement apparatus 100 aggregates the magnetic field strengths detected from the plurality of sensor devices 40 and acquires magnetic field distribution data indicating the strength distribution of the magnetic field generated from the brain. This magnetic field distribution data may be graphically represented as an isomagnetic diagram.

  MEG is an excellent measuring device in both time resolution and spatial resolution. Therefore, MEG is expected as an effective tool for elucidating the mechanism of the human mind as well as clinical diagnosis of the brain. However, the MEG is a device for obtaining a magnetic field distribution, and is not a device for acquiring a brain image itself. Therefore, it is necessary to accurately identify from which part of the brain the magnetic field detected by the MEG is generated.

  Widely used MRI is a measuring device that can image the inside of a living body by utilizing a nuclear magnetic resonance phenomenon. Therefore, if the magnetic field distribution data measured by the MEG is superimposed on the MRI image, the magnetic field generation source can be easily identified visually. In order to superimpose the MRI image and the magnetic field distribution data, it is necessary to determine a reference point for the alignment. In order to determine the reference point, a first marker 10 and a second marker 20 described later are used. In the following, first, after describing the functional blocks of the biological measurement apparatus 100, a method for overlaying the MRI image and the magnetic field distribution data will be described.

FIG. 2 is a functional block diagram of the biological measurement apparatus.
Each block shown here can be realized in hardware by an element such as a CPU of a computer or a mechanical device, and in software it is realized by a computer program or the like, but here it is realized by their cooperation. Draw functional blocks. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by a combination of hardware and software.

The 1st marker 10 is a marker which contains a water | moisture content inside, and is installed in the predetermined position of a test subject's head. The imaging unit 110 images the subject in a state where the first marker 10 is attached. The imaging unit 110 includes a first imaging unit 132 and a second imaging unit 134. The first imaging unit 132 images the subject's brain based on the principle of MRI. At this time, since the moisture of the first marker 10 is detected by the first imaging unit 132, the first marker 10 is projected in the MRI image. Moreover, the 2nd imaging part 134 images a test subject as a normal digital camera from the front. Naturally, the first marker 10 itself is reflected in the appearance image of the subject imaged by the second imaging unit 134. The image data holding unit 114 holds MRI image and appearance image data.
The irradiation part 130 irradiates the position where the 1st marker 10 was attached with reference to this external appearance image, after the 1st marker 10 is removed from a test subject. For this reason, even after the 1st marker 10 is removed, it can confirm where the 1st marker 10 was attached to the test subject.

  The second marker 20 is a marker that generates a magnetic field by a built-in electromagnetic coil, and is installed at the same position as the position where the first marker 10 was installed. The magnetic field measurement unit 112 acquires magnetic field distribution data indicating the intensity distribution of the magnetic field generated from the subject's brain according to the principle of MEG. The magnetic field distribution data holding unit 116 holds magnetic field distribution data.

  The user interface processing unit 128 is in charge of processing related to the entire user interface, such as input processing from the user and information display to the user. The data processing unit 120 executes various data processing based on data acquired from the user interface processing unit 128, the image data holding unit 114, the magnetic field distribution data holding unit 116, and the like. The data processing unit 120 also serves as an interface among the user interface processing unit 128, the image data holding unit 114, the magnetic field distribution data holding unit 116, the imaging unit 110, and the magnetic field measurement unit 112.

The data processing unit 120 includes a first marker detection unit 122, a second marker detection unit 124, and a position adjustment unit 126.
The first marker detection unit 122 detects the position of the first marker 10 from the MRI image and the appearance image. The second marker detection unit 124 detects the position of the second marker 20 from the magnetic field distribution data. The position adjustment unit 126 positions the first marker 10 projected on the MRI image and the second marker 20 projected on the magnetic field distribution data, thereby associating the MRI image with the magnetic field distribution data.

FIG. 3 is a diagram illustrating a marker attachment position.
Typically, a total of five markers are attached, three on the subject's forehead and one on each “recess”. However, it is difficult for the “dent” to match the mounting positions of the first marker and the second marker. Therefore, in the present embodiment, the ear hole is used as the marker installation position instead of “indentation”.

  In this embodiment, each marker is installed at five locations, installation positions 50a to 50e shown in FIG. First, the first marker 10a is installed at the installation position 50a, the first marker 10b is installed at the installation position 50b,..., And the first marker 10e is installed at the installation position 50e. Among these, the 1st marker 10a and the 1st marker 10e have the shape of an earphone type, and can be inserted in an ear hole as it is. On the other hand, the installation positions 50b to 50d are predetermined positions on the forehead, and the first markers 10b to 10d are attached by tape. After the five first markers 10 are installed, the first imaging unit 132 captures an MRI image. Next, the second imaging unit 134 captures an appearance image. When the imaging is completed, the first marker 10 is removed.

  Next, the second marker 20a is installed at the installation position 50a, the second marker 20b is installed at the installation position 50b,..., And the second marker 20e is installed at the installation position 50e. Among these, the 2nd marker 20a and the 2nd marker 20e also have an earphone type shape, and can be inserted into the ear hole as they are. On the other hand, the second markers 20b to 20d are attached to the installation positions 50b to 50d with a tape. After the five second markers 20 are installed, the magnetic field measurement unit 112 acquires magnetic field distribution data.

  Here, since the installation position 50a and the installation position 50e are both ear holes, the installation positions of the first marker 10 and the second marker 20 are easily matched. However, since the installation positions 50b to 50d do not correspond to clear marks on the human body such as ear holes, it is difficult to match the positions of the first marker 10 and the second marker 20. Therefore, the installation positions 50b to 50d are made easy to match the positions of the two types of markers by the irradiation process as shown in FIG.

FIG. 4 is a schematic diagram when irradiating the position of the first marker.
The second imaging unit 134 images the subject to which the first marker 10 is attached from the front. At this time, the 1st marker detection part 122 specifies the position coordinate in the test subject's face of the installation position 50b-50d to which the 1st marker 10b-10d was attached from the height and the width | variety of a test subject's face. For example, the installation position 50c is a position that is lowered from the top of the head by a quarter of the face length h, and is exactly the center when viewed from the width w of the face. The installation position 50b is shifted from the installation position 50c by 1/6 of the face width w. The installation position 50d is also a position shifted in the opposite direction from the installation position 50c by 1/6 of the face width w. In this manner, the positions of the installation positions 50b to 50d on the subject's face are digitized as position coordinate data. When the imaging of the MRI image and the appearance image is completed, the first marker 10 is removed from the subject.

  Next, the irradiation unit 130 irradiates the corresponding portion of the subject's forehead with laser light based on the position coordinate data of the installation positions 50b to 50d in the appearance image. In this state, if the second markers 20b to 20d are pasted in accordance with the irradiation position, as a result, the positions of the first marker 10 and the second marker 20 can be matched.

FIG. 5 is a schematic diagram showing the correspondence between the MRI image and the magnetic field distribution data.
On the MRI image 60, the installation positions 50a to 50e where the first marker 10 is installed are projected. The magnetic field distribution data 70 is graphically represented as an isomagnetic force diagram, and a magnetic field generated by the second marker 20 is projected thereon. Since the first marker 10 and the second marker 20 are installed at the same position, the installation positions 50a to 50e appearing in the MRI image 60 overlap with the installation positions 50a to 50e appearing in the magnetic field distribution data 70. Then, the magnetic field distribution data 70 and the MRI image 60 can be correctly superimposed.

FIG. 6 is a screen view of a user interface screen.
The user interface processing unit 128 displays the MRI image 60 on the user interface screen 200. In the figure, an MRI image 60 with the brain cut from various angles is displayed. Here, the position of the first marker 10 is indicated by a square mark in the figure, and the position of the second marker 20 is indicated by a cross-shaped mark. When the alignment button 202 is clicked, the position adjustment unit 126 displays the magnetic field distribution data 70 so as to overlap the MRI image 60.

In the above, this invention was demonstrated based on the Example.
First, according to the present Example, about the marker attached to a forehead, it becomes easy to attach the 1st marker 10 and the 2nd marker 20 to the same position by irradiation processing. In addition, since the ear hole is used as a marker instead of the “dent”, the first markers 10a and 10e and the second markers 20a and 20e can be easily attached to the same position. By targeting the ear hole, the subject can easily attach the marker himself. Therefore, it is particularly effective when the subject is a woman or an infant. Moreover, since a vitamin E tablet and an electromagnetic coil are only incorporated in a commercially available earphone, the ease of manufacture is also an advantage.

  In the present embodiment, the image inside the brain is acquired by MRI. However, the first imaging unit 132 images the inside of the human body such as X-rays, PET (Positron Emission Tomography), and ultrasound. The human body may be imaged by other known means. Then, magnetic distribution data by MEG may be superimposed on the human body image obtained in this way.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. is there.

  Further, it should be understood by those skilled in the art that the functions to be fulfilled by the constituent elements described in the claims are realized by the individual function blocks shown in the present embodiment or their linkage.

It is a schematic diagram for demonstrating the basic principle of MEG. It is a functional block diagram of a biological measurement apparatus. It is a figure which shows the attachment position of a marker. It is a schematic diagram when irradiating the position of a 1st marker. It is a schematic diagram which shows the correspondence of an MRI image and magnetic field distribution data. It is a screen figure of a user interface screen.

Explanation of symbols

  10 First marker, 20 Second marker, 30 Axon, 32 Synaptic gap, 34 Cell body, 36 Head surface, 38 Magnetic field lines, 40 Sensor device, 42 Magnetic flux detection coil, 44 SQUID, 50 Installation position, 60 MRI image, 70 Magnetic field distribution data, 100 Biological measuring device, 110 Imaging unit, 112 Magnetic field measurement unit, 114 Image data holding unit, 116 Magnetic field distribution data holding unit, 120 Data processing unit, 122 First marker detection unit, 124 Second marker detection unit, 126 position adjustment unit, 128 user interface processing unit, 130 irradiation unit, 132 first imaging unit, 134 second imaging unit, 200 user interface screen, 202 alignment button.

Claims (5)

A first marker attached to the human body;
A first imaging unit that captures an image of the inside of the human body with the first marker attached, and obtains a first captured image on which the first marker is projected;
A second imaging unit that captures an image of the outside of the human body with the first marker attached, and obtains a second captured image that indicates an attachment position of the first marker;
An irradiation unit that irradiates a position on the human body to which the first marker was attached with reference to the second captured image;
A second marker attached to the human body and generating a magnetic field by itself;
A magnetic field measurement unit for measuring the intensity of a magnetic field generated from the inside of the human body in a state where the second marker is attached in accordance with an irradiation position on the human body to which the first marker is attached;
A biological measurement apparatus comprising:   The biological measurement apparatus according to claim 1, wherein the magnetic field measurement unit measures the intensity of a magnetic field generated with a nerve activity of a brain by a SQUID (Superconducting Quantum Interfarence Device). The living body measurement apparatus according to claim 1, wherein the first imaging unit images the inside of the human body by a magnetic resonance method. A plurality of the first markers and the second markers are attached,
Plurality of said first marker comprises one or two first marker which is insertable formed to ear, and the other of the first marker,
A plurality of the second marker includes a second marker which is insertable formed in one or two ear, and the other of the second marker,
The living body measurement apparatus according to claim 1 , wherein the irradiation unit irradiates a position on the human body to which a first marker other than the first marker inserted into the ear hole is attached. . Imaging the inside of the human body with the first marker attached, and obtaining a first captured image on which the first marker is projected;
Imaging the outside of the human body with the first marker attached, and obtaining a second captured image indicating the attachment position of the first marker;
Illuminating a position on the human body where the first marker was attached with reference to the second captured image;
Measuring the intensity of the magnetic field generated from the inside of the human body in a state where the second marker for generating the magnetic field is attached to the irradiation position on the human body to which the first marker is attached;
The first captured image and the magnetic field distribution so that the position of the first marker on the first captured image matches the position of the second marker on the magnetic field distribution data measured in the measuring step. Overlaying the data,
A biological measurement method comprising:

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