JP2983362B2 - Biomagnetic 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 biomagnetic measuring apparatus, and more particularly to a magnetic resonance imaging apparatus (hereinafter abbreviated as MRI apparatus) or X-ray apparatus for taking a tomographic image of a human body by nuclear magnetic resonance.
Means for capturing a tomographic image of a human body by an X-ray CT apparatus that captures a tomographic image of the human body using X-rays, and further measures a magnetic field generated from each part of the human body, such as the brain, heart, lungs, etc. And a means for estimating the distribution of accumulated dust or iron from its magnetization distribution.

[0002]

2. Description of the Related Art For example, SQUID (Superconducting Qua
The SQUID magnetic measurement device that measures the magnetic field generated from each part of the human body by using the ntum Interference Device) is installed in a space of almost zero magnetic field in the magnetic shield room, measures the magnetic field generated from each part of the human body, In addition to detecting the current dipole, a magnetic field is applied to a specific portion of the human body such as the lung by an external coil, and the magnetization due to the applied magnetic field is also detected. On the other hand, a tomographic image of a human body is captured by an MRI apparatus or an X-ray CT apparatus.
Therefore, it is effective for diagnosis to obtain the positional relationship between the human body parts in the above two measurements and display the active part or the magnetic substance accumulation part where the current dipole occurs on the tomographic image.

[0003] As seen in Japanese Patent Application Laid-Open No. Hei 3-60637, a method using a computer common to both an MRI apparatus and an X-ray CT apparatus and a SQUID magnetic measurement apparatus is used to combine the two. The configured magnetoencephalography apparatus has an advantage that the current dipole distribution can be displayed, for example, on a tomographic image of the head, and the accuracy of brain active site diagnosis can be improved.

[0004]

In the above prior art, it is difficult to say that sufficient consideration is always given to the relationship between the position in the human body such as a current dipole obtained from magnetic measurement and the position on a tomographic image. For example, in order to determine the position on the tomographic image of the current flowing through the nerves of the human body, the positions in the human body in the two measurements must match each other with high accuracy. It is necessary to move the human body, which is a subject, to each measurement position for measurement when obtaining the current dipole or when obtaining the current dipole or magnetization distribution in the human body using SQUID. Accordingly, the positional relationship between the two measurements of the human body is shifted due to the movement between the two measurements, and there is a problem in accuracy in obtaining the position on the tomographic image of the current flowing through the nerve of the human body.

The present invention has been made in view of such a problem, and an object of the present invention is to eliminate the need to move a human body at the time of the two measurements and to use a current dipole or a magnetic substance on a tomographic image. An object of the present invention is to provide a biomagnetism measurement device capable of accurately displaying a storage site without displacement.

[0006]

According to the present invention, a tomographic image of a living body, for example, an MRI apparatus for taking a tomographic image of a human body by nuclear magnetic resonance or an X-ray is used. X-ray CT apparatus and SQUI measuring the magnetic field generated from each part of the living body, for example, brain, heart, lung, etc.
As for the ID magnetic measurement device, a part for detecting a biological signal from these two devices is integrated and combined, and two devices, one of an MRI device and an X-ray CT device, and a SQUID magnetic measurement device The computer that processes the measurement data is shared, the current dipole and the magnetization distribution are displayed on the tomographic image that displays the tomographic image of the living body, and the active site or the magnetic material accumulation site can be accurately measured, and that site Can be known accurately.

Further, a means for adjusting the position of the SQUID pickup coil in accordance with the part of the living body to be photographed is provided so that the magnetic field of each part of the living body can be measured with good sensitivity. Moreover, pickup and place the magnetic resonance substances such as pure water in the vicinity of the pickup coil, by M RI apparatus, the detection portion of the raw body and SQUID
The positional relationship with the coil can be measured accurately.

[0008]

[0009]

[0010]

[Function] SQUID magnetic measurement device and MRI device or X
Since the measurement part with the X-ray CT apparatus is integrated, the magnetic field generated from each part of the living body can be measured using the SQUID without moving the living body in a state where the tomographic image of the living body is captured. . In addition, in order to capture a tomographic image, it is necessary to move the part of the living body to be imaged to the center of the static magnetic field coil of the MRI apparatus or the center of the X-ray CT apparatus. By means of which the position of the pickup coil can be adjusted, the SQUID pickup coil can be brought into close contact with each surface of the living body to reduce the distance between the current dipole or magnetic substance inside the living body and the pickup coil, and the direction can be reduced. Because it can be adjusted, it is possible to measure a minute magnetic field generated in a living body with good sensitivity.

As a result, it is possible to accurately determine the position of an affected part in epilepsy, cerebral infarction, heart disease, measurement of magnetization distribution due to dust entering the lung, measurement of magnetization distribution due to iron accumulated in the liver, and the like. it can. In the measurement of the distribution of magnetization in the lungs and the distribution of magnetization due to iron accumulated in the liver, magnetization can be performed using the static magnetic field coil of the MRI apparatus. A special static magnetic field coil for magnetizing the magnet can be omitted.

[0012]

[0013] In addition, magnetic near the pickup coil
Place a resonance substance near the living body and the pickup coil
By magnetic resonance from both of the above magnetic resonance materials
Are detected simultaneously, the pickup coil and
The positional relationship with the unit can be obtained with very high accuracy.
Thereby, it is measured by the SQUID magnetic measurement device.
Apparatus for measuring current dipole or magnetization distribution in living body
Overlaid on the tomographic image of the living body measured by
Thus, highly accurate biological function information can be obtained.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a biomagnetism measuring apparatus according to the present invention. The biomagnetism measuring device of the present invention has a SQUID
It comprises a magnetic measuring device, an MRI device (or an X-ray CT device), a computer, a display device such as a CRT, and a recording device such as a hard disk.

FIG. 2 is a block diagram of the biomagnetism measuring device of the present invention, and FIG. 3 is a magnet and SQUI of the MRI device of the present invention.
FIG. 2 shows a configuration diagram with a D sensor. As shown in FIGS.
The QUID magnetic measurement device is composed of a SQUID 1 and a pickup coil 2 installed in a cryostat 3, and SQUID electronics including an oscillator, a preamplifier, a detector, and the like, which are placed at room temperature. Thus, a minute change in a magnetic field generated from a living body, for example, a certain part of a human body, can be detected as a change in voltage.

By operating several to several tens of SQUIDs at the same time, inputting the voltage output from each SQUID to a computer and solving the inverse problem, the current dipole or magnetization distribution can be obtained. For this purpose, a computer incorporates a program for creating a current dipole or magnetization distribution. On the other hand, the MRI apparatus includes a coil system such as a static magnetic field coil 4, a gradient magnetic field coil, and an RF coil, and a power source for the static magnetic field coil 4 as a driving source thereof, a power source for the gradient magnetic field coil, and an oscillator as an input device for the RF coil. And an RF amplifier, a receiver as an output device of the RF coil, and a detector. The MRI apparatus can energize the static magnetic field coil 4 to generate a static magnetic field and operate the gradient magnetic field coil and the RF coil to obtain a tomographic image of a human body. For this purpose, a computer incorporates a program for creating tomographic images.

Then, the part for diagnosing the human body is placed in the static magnetic field coil 4 of the MRI apparatus, and the pickup coil 2 of the SQUID magnetometer is placed on the body surface of the part. First, a tomographic image of a human body part is taken by an MRI apparatus, and then a SQUID magnetometer is operated to obtain a current dipole or a magnetization distribution. If the SQUID cannot be operated due to the influence of the magnetic field when the static magnetic field coil 4 is energized, the static magnetic field coil 4 of the MRI apparatus is demagnetized before the SQUID operation.
The QUID magnetometer may be operated. Where M
The operation order of the RI device and the SQUID magnetic measurement device may be reversed.

As shown in FIG. 3, the SQUID 1 and the pickup coil 2 of the SQUID magnetometer are installed in the cryostat 3, and the pickup coil 2 is placed near the center of the static magnetic field coil 4 of the MRI apparatus. Thus, the MRI apparatus and the SQUID magnetometer can operate. Then, after the tomographic image of each part of the human body is taken by the MRI apparatus, the magnetic field generated from this part is continuously measured by the SQUID magnetometer.

The operation of the biomagnetism measuring apparatus according to the present invention will be described with reference to the flowchart of the measuring procedure shown in FIG. An MRI apparatus (or an X-ray CT apparatus) captures a tomographic image of a target portion, such as the brain, heart, and lungs of the subject, and takes it into a computer. At this time, the positions of the pickup coils of the plurality of SQUID sensors installed near the target portion are also measured. Next, the magnetic field near the target portion is measured by the SQUID magnetometer. This data is sent to a computer to determine the current dipole or magnetization distribution in the target area. This is a so-called inverse problem of finding a current dipole or magnetization distribution in a living body as a source from a generated magnetic field. As the number of SQUIDs and pickup coils connected thereto increases, the current tie pole or magnetization distribution becomes larger. The accuracy of obtaining the position, intensity, and direction is improved.

The position of the current dipole or the magnetization distribution thus determined is displayed on the tomographic image of the target portion in the next step. Therefore, according to the present embodiment, the active site such as the brain, the heart or the accumulation site of the magnetic substance such as the lung can be accurately displayed on the tomographic image of the target portion as the current dipole distribution or the magnetization distribution, and the There is an effect that the active site or the accumulation site of the magnetic substance can be accurately known. In addition, close to the pickup coil
It has a characteristic X-ray transmittance or shape different from the surrounding
After placing the substance, the living body and SQUI
The positional relationship with the pickup coil, which is the detector of D
It may be possible to measure accurately. In addition, MRI equipment
The sensitivity is highest in the uniform magnetic field in the magnet
Generate a constant magnetic field by adjusting the SQUID
MRI system using a rotating magnet and various parts of the living body
Combination with SQUID magnetic measurement device to measure generated magnetic field
For the SQUID joint.
Optimal critical current value for SQUID operation in the above constant magnetic field
It may be a value. Also, inside the magnet of the MRI device,
SQUID detector near living body under constant magnetic field
Put only the pickup coil, SQUID body
Placement in a low magnetic field is also an effective means. Also, M
SQUID part under a constant magnetic field near the magnet of RI equipment
The magnetic field applied to the SQUID so that the minute can be set
Or a magnetic shield that can reduce
Means that it is effective to provide a coil near the SQUID
Becomes Emitted from each part of the living body using the SQUID sensor
The SQUID magnetometer that measures the generated magnetic field is MR
At the place where the SQUID is installed in the magnet of the I device
SQUID tuned to be most sensitive in magnetic fields
D measures the magnetic field from each part of the living body with high sensitivity
Can be determined. Therefore, the critical current of the SQUID junction
Decreases as the applied magnetic field increases.
The critical current Ic at the SQUID junction under a magnetic field is given by
What is necessary is just to make it hold. Where Φo is the flux quantum and L is the SQUID inductor
It is. In some cases, the pickup coil
Increase the distance between the SQUID and the MRI
SQUID detection near the living body under a constant magnetic field in the net
Place only the pickup coil, which is the output part, and
The SQUID magnetometer can be used to place the ID body in a low magnetic field.
May be effective in increasing the sensitivity of the
Increase the distance between the backup coil and the SQUID
Doing so will slightly increase the noise during the measurement). This is S
Placing a QUID in a magnetic field increases noise in the measurement.
It is inevitable.

[0021]

According to the present invention, the position of the current dipole or the magnetization distribution is accurately superimposed in direct correspondence with the tomographic image of the brain, heart, lung, etc. obtained by the MRI apparatus or the X-ray CT apparatus. Since the active site or the accumulation site of the magnetic substance in the living body can be accurately measured, there is an effect that the site can be accurately known.

[Brief description of the drawings]

FIG. 1 is a block diagram of a biomagnetism measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a biomagnetism measurement apparatus showing one embodiment of the present invention.

FIG. 3 is a configuration diagram of a magnet and a SQUID sensor of the MRI apparatus.

FIG. 4 is a flowchart illustrating the operation principle of the present invention.

[Explanation of symbols]

1 SQUID sensor 2 Pickup coil 3 Cryostat 4 MRI magnet

Claims (3)

(57) [Claims] 1. An imaging unit that captures a tomographic image of a living body, a pickup coil that senses a magnetic field generated from a living body, a SQUID that measures the magnetic field by the pickup coil, and the imaging unit and the SQUID. Processing means for processing the data, and displaying a tomographic image of the living body by the image data from the processing means,
Display means for displaying also a current dipole and a magnetization distribution induced in the living body on the tomographic image, wherein the pickup coil is in imaging means for taking a tomographic image, and A biomagnetism measuring device, which is installed adjacent to the surface of a measurement site of a living body. 2. A means for adjusting the position of a pickup coil of a SQUID according to a relative positional relationship with a living body part to be imaged with respect to a living body entering an imaging means for imaging a tomographic image. The biomagnetic measurement apparatus according to claim 1, wherein: 3. A positional relationship between the pickup coil and a living body is measured by arranging a magnetic resonance substance near the pickup coil of the SQUID and detecting a signal by magnetic resonance between the magnetic resonance substance and the living body. The biomagnetic measurement device according to claim 1, wherein the measurement is performed.