JPH10165393A - Magnetic resonance imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To position a subject by direct visual observation of an imaging region of the subject. SOLUTION: This MRI apparatus is provided with a luminescence means 1 composed of a plurality of illuminants 2 arranged almost in a round shape beneath a magnet for static magnetic field generation 103 in an upper side of the MRI apparatus. The illuminants 2 are arranged corresponding to a position of an imaging region 3. The corresponding region 3 is displayed on a surface of a subject's body in a desired light strength and color by controling a luminescence condition of the illuminants 2 within the imaging region 3 in a luminescence means control circuit of the MRI apparatus. A magnetic field center position is also displayed in its center part together with the imaging region 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance imaging apparatus (hereinafter, referred to as an MRI apparatus), and more particularly to an MRI which can easily align a subject at the time of imaging.
Related to the device.

[0002]

2. Description of the Related Art Conventionally, an MRI apparatus uses a light projector for positioning a subject. Emitter is MRI
It is placed near the end of the magnetic circuit of the device, and before imaging the subject, the light from the projector is applied to the imaging part of the subject placed on the couch top to perform positioning and measurement in the magnetic circuit. The photographing is performed after the top plate is fed into the space by a predetermined amount. Thereafter, when re-aligning the subject, even when the imaging region of the subject is visible from the outside of the apparatus, the top plate on which the subject is mounted is pulled out of the measurement space again, and the desired The top plate is sent to the measurement space again after adjusting to the shooting position.

The following example is disclosed as a conventional example of irradiating a subject, which is sent into a measurement space, with light for alignment or illumination.

Japanese Patent Application Laid-Open No. 63-145463 discloses a technique for illuminating a measurement space with uniform illuminance and comfortable color light using an optical fiber as an optical transmission body in order to remove anxiety from a subject. Have been. Further, in the present invention, in order to notify the subject of the time when the subject needs to be stationary,
Techniques of irradiating light only during that time or blinking light as a signal to start shooting are also disclosed.

Japanese Patent Application Laid-Open No. 4-1055642 discloses a projector for positioning a subject in a measurement space in order to display a center position in at least one of a horizontal direction and a vertical direction of a magnetic field. A technique of irradiating display light to the surface of a subject is disclosed.

Japanese Unexamined Patent Publication No. Hei 5-161626 discloses a process in which the luminous intensity and luminescent color of a illuminant illuminating the inside of a measurement space are measured in order to visually inform the subject of the progress of the imaging. In accordance with the following.

[0007]

In the conventional MRI apparatus, a projector for positioning the subject is provided in the measurement space. However, this projector only displays the center position of the magnetic field, and determines the range of the subject. Could not be seen directly. Therefore, an object of the present invention is to provide an MRI apparatus capable of positioning an object by directly viewing the imaging range of the object.

[0008]

According to an aspect of the present invention, there is provided an MRI apparatus for achieving the above object, comprising a static magnetic field generating means and a gradient magnetic field generating means which are arranged opposite to each other with a measuring space therebetween, and inserted into the measuring space. A high-frequency coil for irradiating the subject with a high frequency to detect a nuclear magnetic resonance signal (hereinafter referred to as an NMR signal) from the subject, and an image for obtaining an image representing a physical property of the subject from the NMR signal M comprising a reconstructing means and a control means for controlling the measurement conditions of the subject
The RI apparatus includes a light emitting unit capable of displaying a photographing range of the image in the measurement space (claim 1).

In the MRI apparatus according to the present invention, the light emitting means can display a magnetic field center position. In this configuration, the light emitting means is arranged in the measurement space, and the imaging range of the captured image and the magnetic field center position can be displayed. Therefore, the subject can be positioned by directly viewing the imaging range.

In the MRI apparatus according to the present invention, the light emitting means can illuminate the subject inserted into the measurement space. With this configuration, the subject in the measurement space can be illuminated, so that in an open MRI apparatus, the light-emitting means can be used as illumination during surgery or healing of the subject.

[0011] The MRI apparatus of the present invention further comprises a light emitting means control circuit for controlling light emitting conditions of the light emitting means. In this configuration, various light emission conditions of the light emitting means can be controlled by the light emitting means control circuit.

Further, in the MRI apparatus of the present invention, the light emitting means includes a plurality of light emitters, and the light emitters are arranged so as to face the subject in association with positions within a maximum imaging range. The luminous condition of the luminous body is controlled by the luminous means control circuit in association with the position of the subject within the imaging range (claim 5).

[0013] In this configuration, the light-emitting elements constituting the light-emitting means are arranged and controlled in association with the positions in the photographing range, so that the photographing range can be easily displayed by setting the photographing range and the light-emitting condition. Will be

Further, in the MRI apparatus of the present invention, at least one of the luminous intensity and the luminous color of the luminous body is controlled so as to change in association with the position of the subject within the imaging range. Claim 6). In this configuration,
The light intensity and the light color within the photographing range can be changed in association with the position.

[0015] In the MRI apparatus of the present invention, the light emitting means control circuit and / or the control means for controlling the measurement conditions of the subject may be arranged near the static magnetic field generating means. , 8). In this configuration, since the light emitting unit control circuit and the control unit are provided close to the subject, the subject can be quickly positioned,
As a result, quick shooting is possible.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a first light emitting device of the present invention.
FIG. 2 shows the configuration of an MRI apparatus to which the light emitting device is attached. In FIG. 2, an MRI apparatus includes a static magnetic field generating magnet 103 for generating a static magnetic field in a measurement space 102 into which a subject 101 is inserted.
A gradient magnetic field coil 104; a high-frequency coil 105 for irradiating the subject 101 with high frequency or detecting an NMR signal emitted from the subject 101;
Bed 107 to be placed on 06 and inserted into measurement space 102
A gradient magnetic field power supply 108 for supplying power to the gradient magnetic field coil 104; a high frequency transmitting / receiving circuit 109 for supplying high frequency power to the high frequency coil 105 and detecting an NMR signal detected by the high frequency coil 105; Light-emitting device 1 for irradiating light to the light-emitting device, light-emitting device control circuit 110 for controlling light-emitting device 1,
Including an image reconstructing means for obtaining an image representing the physical properties of the subject 101 based on the signal, a gradient magnetic field power supply 108, a high-frequency transmission / reception circuit 109, a bed 107, a light emitting device control circuit 1
A control circuit 111 for controlling the control circuit 10 and the like;
And an operation console 112 for operating the operation console 1.

As shown in FIG. 2, the light emitting device 1 is installed on the surface of the upper magnet 103 of the static magnetic field generating magnet 103 opposed to the upper and lower sides of the MRI apparatus facing the subject 101. FIG. 1 is an overall perspective view of a first embodiment of the light emitting device. In FIG. 1, a light emitting device 1 includes a plurality of light emitting bodies 2.
And attached to the lower surface of the upper static magnetic field generating magnet 103. It is arranged closer to the subject 101 than the gradient coil 104 and the high-frequency coil 105 so that there is no obstacle between the subject 101 and the light emitter 2 that blocks light. The plurality of light emitters 2 are in close contact with each other in a circular, elliptical, or rectangular shape having a size corresponding to the maximum imaging range of the subject 101 so that the size of the imaging range 3 of the subject 101 can be displayed. It is arranged as. Each of the light emitters 2 generates a parallel light beam, and is controlled by the light emitting device controller 110 so that only the light emitters 2 corresponding to the imaging range 3 set on the console 112 or the outer periphery 4 thereof emit light. When the light-emitting body 2 emits light, it is more preferable that the light-emitting body 2 corresponding to the outer periphery 4 of the photographing range 3 emit light than the light-emitting body 2 corresponding to the entire area of the photographing range 3 emits light. Since the number of the bodies 2 is small, the light emitting device 1
Consumes less power and is more efficient.

The imaging range 3 of the subject 101 is controlled by the control circuit 1
It is set as a FOV (photographing range) at 11,
Data is input from the console 112 by key operation. The association between the irradiation range of the light-emitting body 2 of the light-emitting device 1 and the horizontal coordinate system of the FOV is performed between the position of each light-emitting body 2 and the corresponding coordinate in the FOV. Is set, the corresponding light emitter 2 is designated, the designated light emitter 2 is turned on via the light emitting device control circuit 110, and the imaging range 3 (or the outer periphery 4) of the subject 101 is displayed. become.

By controlling the light emitting device 1 as described above,
When the light is emitted, the imaging range 3 or the outer periphery 4 thereof can be displayed on the upper surface of the subject 101 having unevenness by light. When the light generated by the light emitter 2 is not a parallel light beam, the imaging range 3 displayed on the body surface changes depending on the size of the subject 101 (when the subject 101 is large, the imaging range 3 is small, (When 101 is small, the photographing range 3 becomes large.) Therefore, each light emitting body 2 is provided with a convex lens for converting into a parallel light beam. Also,
There is a laser beam as the luminous body 2 that generates a parallel ray,
When this is used, it is necessary to prevent light from directly entering the eye of the subject 101.

FIG. 3 shows a light emitting device according to a second embodiment of the present invention. The light emitting device 1 is attached to the lower surface of the upper magnet 103 as in the first embodiment. The luminous body 2 of the present embodiment is a luminous body 2 that displays the imaging range 3 of the subject 101, particularly, the periphery 5 or the outer periphery 4 of the imaging range 3.
A and a luminous body 2B indicating the magnetic field center position 6.
The peripheral portion 5 or the outer periphery 4 of the imaging range of the subject 101 is displayed by the light emitter 2A, and the magnetic field center position 6 is displayed by the light emitter 2B. As a result, the inspector can simultaneously observe both the peripheral portion 5 or the outer periphery 4 of the imaging range and the magnetic field center position 6. In this case, the luminous body 2B corresponding to the magnetic field center position 6 is usually located at the center of the entire luminous body 2, and the luminous body 2 around the luminous body 2B should be removed so that the magnetic field center position 6 can be easily identified. Or control not to emit light.

FIGS. 4 to 7 show display examples of the imaging range of the subject and the center position of the magnetic field by the luminous body according to the present invention.
In each case, the case where the imaging range is circular is illustrated. In FIG. 4, only the luminous body 2 is displayed for the imaging range 3 of the subject 101, but the light intensity of the luminous body 2 is changed between the central portion 7 and the peripheral portion 5 of the imaging range 3. . That is, the intensity of light at the central portion 7 is reduced, and the intensity of light at the peripheral portion 5, particularly the outer periphery 4, is increased. The lower figure shows the light intensity distribution 21 in the photographing range 3. By displaying in this manner, the outer periphery 4 of the photographing range 3 becomes easy to see. The control of the light intensity of the light emitters 2
The light emitting device control circuit 110 controls the light source power.

In FIG. 5, both the imaging range 3 of the subject 101 and the magnetic field center position 6 are displayed. As shown in the light intensity distribution 21 of the light emitters in the lower diagram, the light emitter 2B corresponding to the magnetic field center position 6 does not emit light, and the other light emitters 2 in the imaging range 3 emit light with uniform intensity. I have. In this example, the magnetic field center position 6 is displayed as a dark point, and the other imaging ranges 3 are displayed with uniform brightness.

In FIG. 6, both the outer periphery 4 of the imaging range 3 and the magnetic field center position 6 are displayed. As shown in the light intensity distribution 21 of the luminous body in the lower diagram, the luminous body 2 corresponding to the outer periphery 4 of the imaging range 3 and the luminous body 2B corresponding to the magnetic field center position 6 emit light with the same intensity. In this example, the outer periphery 4 of the imaging range 3 and the magnetic field center position 6 are displayed with uniform brightness. Here, with respect to the luminous body which displays the magnetic field center position 6, if only one luminous body is insufficient, the luminous bodies around the luminous body may be illuminated so that the magnetic field center position 6 can be clearly seen.

In FIG. 7, the display of the center position of the magnetic field is changed from the display example of FIG. 6, and a circle mark is replaced with a plus sign 6A. As a method of the + mark display 6A, the light exit of the luminous body 2B for displaying the center position of the magnetic field has a +
A method of attaching a mask with a hole of a mark, or arranging another luminous body 2 in a + shape around the luminous body 2B, combining a plurality of luminous bodies and displaying a + mark, etc. is there.

Although not shown in FIGS. 4 to 7, there is also a method in which the luminous body 2A for displaying the photographing range 3 and the luminous body 2B for displaying the center position 6 of the magnetic field are displayed in different colors.
In this case, since the emission colors of the two are different, the two are more clearly distinguished from each other, and are very easy to see. Regarding the display of the photographing range 3, it is also possible to change the luminescent color between the inner peripheral portion and the outer peripheral portion, or to change the luminescent color stepwise from the inner peripheral portion to the outer peripheral portion. Furthermore, a combination of changing the light intensity of the light emitter and changing the color is also conceivable. That is, as in the display example of FIG. 4, the light intensity is changed between the inner and outer peripheral portions, and the color of light is also changed between the inner and outer peripheral portions. The effect of discriminating the shooting range is significantly improved.

In the display examples shown in FIGS. 6 and 7, it is sufficient that the center positions 6 and 6A of the magnetic field and the outer periphery 4 of the photographing range 3 are clearly identified, and the intensity and color of the light are not particularly limited. Absent. In FIG. 7, the display of the magnetic field center position is +
Although the mark 6A is shown, this display may be any symbol as long as the center position of the magnetic field can be identified, and is not limited to the plus sign. For example, it may be a diamond, a star, a triangle, or the like.

FIG. 8 shows an embodiment of the structure of the luminous body of the present invention. FIG. 8A is a diagram showing a cross section of the structure of the light emitting body 2. The luminous body 2 has a light source 13 disposed near a bottom 12 of a cylinder 11 having a bottom, and an opening 14 is attached to a front surface 15 of the light emitting device 1. The light source 13 is installed near the bottom 12 of the cylinder 11 so that the light source 1
The light 16 from 3 passes through the inside of the cylinder 11 and becomes almost parallel rays. However, it is desirable that the inside of the cylinder 11 be covered with a material that reflects light.

The configuration shown in FIG. 8A can also be achieved by providing a light emitting device installation hole in the light emitting device 1 and installing the light source 13 deep in the hole.

FIG. 8B shows the light source 1 in the case of FIG.
FIG. 3 is a cross-sectional view of a case in which 3 is moved near an opening 14 of a cylinder 11. In this example, the light-emitting body 2 is provided with a mechanism for moving the light source 13 up and down so that the light source 13 can move near the opening 14 of the cylinder 11. With such a configuration, light emitted from the light source 13 becomes diffused light, and light can be applied to a wider range than parallel light, so that it can be used for irradiating the subject 101.

FIG. 8C shows an example in which the light source 13 of the light emitting body 2 is small. In this case, since the light from the light source 13 is diffused light, the divergent light is converted into the parallel light 16 by the convex lens 17 at the opening 14 of the cylinder 11.

When the luminous body 2 shown in FIG. 8B is applied to the light emitting device 1, the irradiation range of the light from the luminous body 2 is the object 101.
Is larger than the imaging range 3, it can be used for illuminating the subject 101, which leads to a reduction in the feeling of pressure felt by the subject 101 in the measurement space 102. Further, when applied to an open MRI apparatus, it can be used as illumination for surgery or treatment of the subject 101.

Further, the luminous body 2 shown in FIG.
When applied to the circle, point, +
The mark or the like is enlarged or reduced on the body surface of the subject 101 by moving the installation position of the light source 13 or the installation position of the convex lens 17.

Using the light emitting device 1 described above, the subject 10
In the case of performing the alignment of 1 and the display of the photographing range 3, in order to perform photographing quickly, a simple operation console for setting photographing conditions and instructing photographing is installed in the shielded room.
It is installed near the static magnetic field generating magnet 103 of the RI device. In addition, a part of the light emitting device control circuit 110 such as a switch for starting light emission of each light emitting body 2 of the light emitting device 1 and an adjustment button for adjusting light emission intensity is also provided with a magnet for generating a static magnetic field in order to quickly perform imaging. It is installed near 103.

[0034]

As described above, according to the present invention, M
In the RI apparatus, the imaging range of the subject and the center position of the magnetic field can be displayed on the body surface of the subject, and the setting of the imaging range of the subject and the positioning of the subject can be performed in the vicinity of the static magnetic field generating magnet. As a result, quick imaging can be performed, and the throughput can be improved.

In addition, by using the light emitting device of the present invention for illuminating a subject, surgery and treatment of the subject can be performed quickly and accurately under the illumination.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a light emitting device according to the present invention.

FIG. 2 is a diagram showing a configuration of an MRI apparatus to which the light emitting device of the present invention is attached.

FIG. 3 is a diagram showing a second embodiment of the light emitting device of the present invention.

FIG. 4 is a display example of an imaging range of a subject by a luminous body according to the present invention.

FIG. 5 is a display example of an imaging range of an object and a center position of a magnetic field by a light-emitting body according to the present invention.

FIG. 6 is a display example of the outer periphery of the imaging range and the center position of the magnetic field by the luminous body according to the present invention.

FIG. 7 is a modification example of FIG. 6;

FIG. 8 shows an embodiment of the structure of the luminous body of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light-emitting device 2, 2A, 2B light-emitting body 3 Imaging range 4 Perimeter of imaging range 5 Perimeter of imaging range 6, 6A Magnetic field center position 7 Center of imaging range 11 Cylinder 12 Bottom 13 Light source 14 Opening 15 Front of light-emitting device Reference Signs List 16 light beam 17 convex lens 21 light intensity distribution 101 subject 102 measurement space 103 static magnetic field generating magnet 104 gradient magnetic field coil 105 high frequency coil 106 top plate 107 bed 108 gradient magnetic field power supply 109 high frequency transmission / reception circuit 110 light emitting device control circuit 111 control circuit 112 Console

Claims (8)

[Claims] 1. A static magnetic field generating means and a gradient magnetic field generating means which are arranged opposite to each other with a measurement space therebetween, and irradiate a test object inserted into the measurement space with a high frequency. A high-frequency coil for detecting a nuclear magnetic resonance signal (hereinafter referred to as an NMR signal); an image reconstructing means for obtaining an image representing a physical property of the subject from the NMR signal; and a control means for controlling measurement conditions of the subject. A magnetic resonance imaging apparatus comprising: a light-emitting unit capable of displaying a photographing range of the image in the measurement space. 2. The magnetic resonance imaging apparatus according to claim 1, wherein said light emitting means can display a magnetic field center position. 3. The magnetic resonance imaging apparatus according to claim 1, wherein said light emitting means is capable of illuminating a subject inserted into said measurement space. 4. The magnetic resonance imaging apparatus according to claim 1, further comprising a light emitting means control circuit for controlling a light emitting condition of said light emitting means. 5. The magnetic resonance imaging apparatus according to claim 1, wherein the light emitting means includes a plurality of light emitters, and the light emitters face the subject in association with a position within a maximum imaging range. A magnetic resonance imaging apparatus, wherein the light emission condition of each light emitter is controlled by the light emitting means control circuit in association with a position of the subject within an imaging range. 6. The magnetic resonance imaging apparatus according to claim 4, wherein at least one of the luminous intensity and the luminous color of the luminous body is controlled so as to change in association with a position of the subject in an imaging range. A magnetic resonance imaging apparatus. 7. A magnetic resonance imaging apparatus according to claim 1, wherein said light emitting means control circuit is arranged near said static magnetic field generating means. 8. The magnetic resonance imaging apparatus according to claim 1, wherein control means for controlling the measurement condition of the subject is arranged near the static magnetic field generating means. apparatus.