JP2001128955A - Nuclear magnetic resonance imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear magnetic resonance imaging system in which the degree of freedom for movement of a top plate for placing a subject thereon is increased and the image quality of an MRI image is not influenced without using a motor as a driving source for the movement. SOLUTION: The MRI system of this invention is equipped with an MRI apparatus body G having a photographing space part H to which a static magnetic field, a magnetic field for excitation and an inclined magnetic field are applied, and a receiving coil 2 for receiving an NMR signal detected from the subject P. This system further has floating top plate 11 for placing the subject P directly thereon, and a base 10 for fixing the top plate 11 in a designated position at the time of tomographic photographing. The top plate 11 can be held in a floating state by pneumatic force. Floating of the top plate 11 is effected by pushing up the top plate 11 with the compressed air blown out of an air passing hole 10d on the surface of the base 10 connected to an air compressor 10a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear magnetic resonance imaging apparatus, and more particularly to a bed which is a component of the apparatus and has improved operability.

[0002]

2. Description of the Related Art A nuclear magnetic resonance imaging apparatus is a nuclear magnetic resonance signal (NMR signal) obtained by applying an excitation magnetic field (RF magnetic field) and a gradient magnetic field to a subject placed in a static magnetic field space. Is a device for reconstructing a nuclear magnetic resonance imaging (MRI) image (tomographic image) of the subject based on the. According to this, unlike an X-ray CT apparatus, an obtainable tomographic image is naturally limited by the installation state of an X-ray detector, but a free cross section is assumed for a subject, and the tomographic image is obtained. Has many advantages, such as the ability to obtain

[0003] As such a nuclear magnetic resonance imaging apparatus, for example, an apparatus shown in FIG. 9 has been conventionally provided. In FIG. 9, a subject P lies on a bed 1 having a top board 1a which is installed so as to be able to translate in the depth direction in the figure. The receiving coil 2 for receiving the above-mentioned NMR signal is installed on the top plate 1a. Although the receiving coil 2 in FIG. 9 is shown as an example for photographing the knee of the subject P, in the case of a general receiving coil, the installation position of the receiving coil 2 with respect to the top plate 1a is different from the position of the receiving coil for which a tomographic image is to be obtained. It will be adjusted in advance so as to match the site related to the sample P.

On the other hand, a main magnet, an RF coil, and a gradient coil for forming a static magnetic field, an RF magnetic field, and a gradient magnetic field are provided in an MRI apparatus main body G having an imaging space H in which a static magnetic field space is formed. (Both not shown) are arranged. As shown in FIG. 8, the imaging space H has a shape in which the main body G of the MRI apparatus is hollowed out from its side in a U-shaped cross section. Therefore, the shooting space H is
As shown in FIG. 9, it has an opening Ha.

[0005] The nuclear magnetic resonance imaging apparatus having such a configuration is a so-called "open type", which does not cause the subject P to feel a feeling of oppression, and furthermore, the MRI examination. In addition, many advantages can be enjoyed, such as a surgeon's operation or direct examination can be performed in parallel using the opening Ha. Note that this open type MRI apparatus is used in such a manner that the top plate 1a of the bed 1 is introduced into the imaging space H as shown by an arrow A in FIG.
Then, the MRI imaging is started after the center of the magnetic field of the main magnet, the RF coil and the like is matched.

[0006]

The above-mentioned open type MRI apparatus has the following problems. The problem is that the couchtop 1a of the couch 1 is configured to be driven by a motor. More specifically, the conventional couchtop 1a has a bearing and an appropriate guide or guide with respect to the couch body 1b. It is grounded via a rail or the like (neither is shown), and this configuration and the motor make it possible to move the top plate 1a.

As described above, in the form in which the top board 1a is driven by a motor, first, there is a problem that the movement of the top board 1a is greatly restricted in its direction and the like. In the example shown in FIG. 9, it can be seen that the direction of movement of the top 1a is restricted only in a certain direction indicated by arrow A in the figure. In this case, when a doctor's operation or the like is performed in parallel, and when it is desired to change the “direction” of the subject P, the doctor himself or herself must change the posture or reset the subject P itself. Must. That is, in the above-described conventional configuration, it is possible to perform the operation or the like functionally in an “open MRI apparatus” in which it is expected that the doctor's operation or the like and the MRI examination are realized in parallel. It could not be said that the original potential of the device was fully utilized.

Driving the top plate 1a with a motor is as follows.
The problem is that the MRI image is affected by deteriorating the image quality. That is, the motor has a structure for rotating the brush, as is well known, and gives fluctuation (noise) of the electromagnetic field to the outside world. However, this is not necessarily a preferable situation for MRI imaging in which it is originally planned to reconstruct a tomographic image of the subject P placed in the “constant static magnetic field space”. If MRI imaging is performed with such noise remaining, the deterioration of the image quality is inevitable. Therefore, in the related art, when performing MRI imaging after performing motor driving related to movement of the top board 1a or the like, measures have been taken after waiting for the noise to attenuate over time. However, this recognizes the occurrence of dead time in the operation of the MRI apparatus, which obviously leads to inefficient operation.

Further, if the motor is an essential component, the space for accommodating the motor must be provided in the bed 1. Therefore, the configuration of the bed 1 is correspondingly large and it is difficult to reduce the size. There was also a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to increase the degree of freedom relating to the movement of a top plate on which a subject is mounted, and to use a motor as a drive source for the top plate. An object of the present invention is to provide a nuclear magnetic resonance imaging apparatus which does not affect the image quality of an MRI photographed image unlike the case where the apparatus is employed.

[0011]

The present invention employs the following means in order to solve the above problems.

That is, a nuclear magnetic resonance imaging apparatus according to a first aspect of the present invention provides an excitation means for applying an excitation magnetic field to a subject arranged in a static magnetic field space, and a gradient magnetic field application for applying a gradient magnetic field to the subject. And an apparatus main body having an imaging space in which the static magnetic field space is formed, and a receiving unit for receiving an NMR signal detected from the object, and the object introduced into the imaging space. In a nuclear magnetic resonance imaging apparatus that captures a tomographic image, a top plate on which the subject is directly mounted, a base that fixes the top plate at a predetermined position when capturing the tomographic image, and the top plate, A top plate floating means capable of holding the surface of the base in a floating state by pneumatic force is provided.

According to a second aspect of the present invention, in the nuclear magnetic resonance imaging apparatus according to the first aspect, the aerodynamic force is:
With respect to the configuration of the air sending means and the plurality of air holes formed on the surface of the base connected to the air sending means, the pressure is the pressure when air is blown out from the air holes. And

According to a third aspect of the present invention, in the nuclear magnetic resonance imaging apparatus according to the first aspect, the aerodynamic force is:
With respect to the configuration of the air sending means and the plurality of air holes formed on the top plate surface connected to the air sending means, the pressure is the pressure when air is blown out from the air holes. And

According to a fourth aspect of the present invention, there is provided a nuclear magnetic resonance imaging apparatus according to the second or third aspect, wherein a valve is interposed between the air delivery means and the air passage, and the valve is opened and closed. Control means is provided for controlling the mode of air ejection from the air holes through the control.

According to a fifth aspect of the present invention, there is provided the nuclear magnetic resonance imaging apparatus according to any one of the second to fourth aspects, further comprising a restraining means for restricting a moving range of the top plate on the base. It is characterized by being able to.

The nuclear magnetic resonance imaging apparatus according to the sixth or seventh aspect is the same as the fifth aspect,
The restraining means may be a plate placed on the base, or the restraining means may be a block installed on the base.

[0018] Finally, a nuclear magnetic resonance imaging apparatus according to claim 8 is the apparatus according to any one of claims 1 to 7, wherein the imaging space portion is before or after the tomographic imaging or at or after the tomographic imaging. In the meantime, the apparatus has an opening that allows surgery or the like on the subject.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a nuclear magnetic resonance imaging apparatus (hereinafter referred to as M) according to the first embodiment.
FIG. 1 is a schematic diagram illustrating a configuration example of an RI device). In addition,
In the following description, reference numerals used in FIG.
Also in the embodiment according to the present invention, the same reference numerals as those in FIG.

In FIG. 1, this MRI apparatus includes an MRI apparatus main body G having an imaging space H in which a static magnetic field space is formed. As shown in FIG. 1, the imaging space portion H is a space portion formed so as to be cut out from the side surface of the MRI apparatus main body G having a substantially rectangular parallelepiped shape in a U-shaped cross section. Therefore, the photographing space H has an opening Ha. Surgery by a doctor or the like, direct inspection, or the like before, after, or in some cases during MRI imaging is performed using the opening Ha. Also, MRI
In the apparatus main body G, a static magnetic field, RF
A magnetic field, a main magnet for forming a gradient magnetic field, an RF coil (excitation means), and a gradient magnetic field coil (gradient magnetic field application means) (all not shown) are arranged. Further, M
The RI device also includes an image reconstruction device that reconstructs a tomographic image based on an NMR signal read by a receiving coil (reception unit) 2 (described later), a display device that displays the tomographic image, and control of these devices. A control device (both not shown) for performing the control is provided.

The MRI apparatus also includes a base 10 on a bottom surface Hb which is one of three surfaces forming the imaging space H. As shown in FIG. 2 which is a cross-sectional view near the surface of the base 10, the base 10 has a cavity 10h therein, and a plurality of air holes 10d communicating with the cavity 10h are formed on the surface. It has become. As shown in FIG. 2, the air holes 10 d are uniformly formed on the entire surface of the base 10. In addition, these blow out compressed air described later in a direction perpendicular to the surface.

As shown in FIG. 1, a hose 10 extending from an air compressor (air sending means) 10a is provided on a side surface of the base 10 so as to communicate with the cavity 10h.
b is connected via the valve 10c. Among these, the control device C is connected to the air compressor 10a and the valve 10c. The air compressor 10a, the hose 10b, the valve 10c, the air hole 10d, and the cavity 10h can be said to constitute "top plate floating means" of the present invention.

Further, a plurality of legs 10e are provided on the back surface of the base 10 in the first embodiment. Base 1
0 is positioned on the bottom surface Hb by the leg 10e. The legs 10e may be of a fixed type or may be provided with a mechanism whose height is variable. In the latter case, in order to realize this, for example, a separate air compressor may be provided, and the leg 10e may be configured to be variable in height using the compressed air as a power source. This makes it possible to change the height position of the base 10.

As shown in FIG. 1, a floating top plate 11 on which a subject P is placed is provided on the base 10.
As shown in FIG. 3, the floating top plate 11 has a surface portion 11A whose shape is an appropriate area for mounting the subject P, and is provided on the four sides on the back side of the surface. An edge 11B protruding perpendicularly to this is provided. In addition, the receiving coil 2 is installed on the floating top 11 along with the subject P on the surface 11A, as shown in FIG. It should be noted that the receiving coil 2 in the figure particularly shows an example of a preferred form for imaging the knee of the subject P. However, the present invention relates to a receiving coil 2 having such a configuration.
Of course, it is not limited to use only.

With the configuration of the base 10 and the floating top plate 11 as described above, compressed air is sent from the air compressor 10a into the cavity 10h in the base 10, and the compressed air is sent from the air holes 10d. They erupt or squirt. Then, the floating top plate 11 is held in a floating state on the surface of the base 10 by the blown compressed air (see FIG. 2).

A stretcher S having a variable height is provided beside the base 10 in order to introduce the floating top plate 11 onto the base 10.

Hereinafter, the operation and effect of the MRI apparatus having such a configuration will be described in accordance with an example of a work procedure when using the MRI apparatus.

First, the subject P is placed on the floating top 11 previously set on the stretcher S. At this time, the receiving coil 2 is also installed. Then, the subject P, together with the stretcher S, the top plate 11 and the receiving coil 2, is brought close to the side of the base 10 and the stretcher S is fixed at an appropriate position. The height of the stretcher S is adjusted so that the height of the stretcher S matches the height of the surface. In this case, if the leg 10e of the base 10 is configured to be variable in height as described above, it is a matter of course that this may be adjusted. However, when adjusting the leg 10e, there is a mismatch between the position of the receiving coil 2 when the floating top plate 11 is introduced on the surface of the base 10 and the center of the magnetic field such as the main magnet and the RF coil. Care must be taken to prevent this from happening.

After the above adjustment is completed, the air compressor 10a is operated via the control device C and the valve 1 is operated.
0c, and an air hole 10d formed in the surface of the base 10.
Blow compressed air from Thereafter, the floating top plate 11 is introduced onto the surface of the base 10. Then, the compressed air that has been blown out accumulates on the back surface of the floating top plate 11, that is, on the air reservoir 11C (see FIG. 2) surrounded by the edge portion 11B, so that the top plate 11 is placed on the base 1
It is held in a state of floating with respect to the zero plane. In such a situation, the movement of the floating top plate 11 can be easily realized only by applying a small force (for example, a force of pushing by hand). Further, the movement can be basically freely performed on the base 10 in any direction.

At this time, the air compressor 10a
The operation of the valve 10c depends on the operation status of the device.
It is controlled by the control device C. That is, for example, depending on whether the subject P placed on the floating top 11 is an adult or a child, the air hole 10d
When it is desired to change the pressure or amount of the compressed air ejected from the air compressor 10a, the controller C controls the operation mode and the like in the air compressor 10a in which the opening degree of the valve 10c or the operation mode can be selected. Note that such control may be performed manually via the control device C. However, in some cases, the floating top plate 11 may be used.
A contact sensor or the like may be provided on the lower surface of the device, and the opening degree of the valve 10c or the operation of the air compressor 10a may be automatically adjusted while the control device C refers to the output of the sensor.

By freely moving the floating top plate 11 as described above, if the position between the receiving coil 2 and the center of the magnetic field such as the main magnet is matched, the operation of the air compressor 10a is stopped, or The flow of the air ejected from the air hole 10d is stopped by closing the valve 10c. As a result, the floating top plate 11 has its back surface (strictly, the lower edge of the edge portion 11B).
At this point, the top plate 11 is fixed in contact with the surface of the base 10. Thereafter, a normal MRI inspection may be performed.

As described above, the MR in the first embodiment is
According to the I device, the floating top plate 11 can be basically moved in a free direction. For example, after the MRI imaging is completed according to the above procedure, if the air compressor 10a is restarted or the valve 10c is opened via the control device C, the floating top 11 can be moved again. Since the state easily transitions to the levitating state, and this movement can be performed in any direction, the direction of the subject P can be easily changed, and the medical treatment of a doctor that can be performed in parallel with the MRI examination is performed. Surgery or examination can be performed extremely functionally.

In the above embodiment, the motor is not used as a power source of the top plate 11 and its movement is made possible only by the aerodynamic force. Therefore, there is no concern that the image quality of the MRI photographed image is affected. Absent. That is,
Since there is no fluctuation (noise) in the electromagnetic field which can be considered when using a motor or the like, after setting the floating table 11, MRI imaging can be started immediately without wasting time, and At the same time, it is possible to acquire an MRI photographed image that always has good image quality.

Further, the fact that there is no need to install a motor means that the structure of the apparatus itself can be made relatively simple as compared with the prior art, and the size of the base 10 can be made suitable beforehand. If that were the case, it would be possible to make it more compact.

Hereinafter, a second embodiment according to the present invention will be described. In the second embodiment, the configuration relating to the base 10 is changed, and the rest is completely the same as the first embodiment. Therefore, description thereof will be omitted below. In the third and subsequent embodiments to be described below, the description of the same components as those in the first embodiment will be omitted.

FIG. 4 is a perspective view mainly showing the appearance of the surface of the base 10 according to the second embodiment. In this figure, a plurality of top plate movement restricting plates (restraining means) 12 are placed on the surface in a planar manner. The top plate movement constraint plate 12
As shown in FIG. 4, the shape is a substantially rectangular parallelepiped shape whose thickness is smaller than the length and width. The size (area) is such that when a plurality of the restraining plates 12 are spread on the surface of the base 10, the entire surface of the base 10 can be completely covered. In FIG. 4, by preparing nine top plate movement constraint plates 12, the entire surface of the base 10 can be covered, and the length and width and the thickness of the floating top plate 11 It can be seen that they are formed to be equal in length and thickness.

As is apparent from FIG. 4, the top plate movement restricting plate 12 has an action of closing the air hole 10d by being placed on the surface of the base 10, and has a function of closing the floating top plate 11. It has the effect of limiting the range of movement on the surface of the base 10. In FIG. 4, seven top plate movement constraint plates 12 are placed on the surface of the base 10 so that the floating top plate 11
It can be seen that the movement is limited to only the left and right directions indicated by arrow B in the figure.

In this manner, the floating top 1
If it is not desired to increase the degree of freedom of movement of the top board 1, the top board movement restraining plate 12 is placed in an appropriate position on the surface of the base 10 so that the floating top board 1 can be moved.
1 can be avoided in advance, and the top plate 11 can be quickly fixed in accordance with MRI imaging. However, even in such a case, if it is desired to freely move the floating top plate 11 later, this can be realized only by removing the top plate movement constraint plate 12, so that the characteristic of the present invention is achieved. It does not constitute any obstacle to hindering one of the effects, "free movement of the tabletop." For example, in FIG. 4, after the floating top 11 is fixed to the center of the base 10 and the MRI imaging is completed, if the top 11 is to be moved to the near side (the lower side in the figure), it is moved. Top plate movement restraint plate 12 corresponding to the position to be set
If a is removed, it can be easily implemented.

Hereinafter, a third embodiment according to the present invention will be described. FIG. 5 shows a base 1 according to the third embodiment.
FIG. 3 is a perspective view mainly showing a state of a surface 0; In this figure, a plurality of top board movement restraining blocks (restraining means) 13 are three-dimensionally provided on the surface. For this installation and fixing, a block fixing hole (not shown) is provided on the surface of the base 10 separately from the air through hole 10d, and a projection ( (Not shown) may be provided. As is apparent from FIG. 5, these top plate movement constraint blocks 13 have the same function as the top plate movement constraint plate 12 in FIG. That is, they have the effect of limiting the range of movement of the floating top plate 11 on the surface of the base 10. In FIG. 5, four blocks 13 each having a rectangular parallelepiped shape and a corner-shaped block 1 corresponding to the corner shape of the top plate 11 are provided on the base 10.
Two pieces 3a are prepared and installed, respectively, and thereby, the moving direction of the floating top plate 11 is limited to only the left-right direction indicated by arrow B 'in the figure.

Even in this case, as in the second embodiment, unnecessary movement of the floating top plate 11 is limited, and the top plate 11 is quickly fixed in accordance with MRI imaging. Can be. If the floating top 11 is to be freely moved later, as in the second embodiment, this can be easily realized by removing the top movement restriction block 13.

Hereinafter, a fourth embodiment according to the present invention will be described. In the fourth embodiment, the configuration regarding both the base and the floating top plate is changed.

FIG. 6 shows a base 10 'according to the fourth embodiment.
It is a schematic diagram showing a configuration of a floating top plate 11 ′. In the MRI apparatus according to the fourth embodiment shown in this figure, the air holes 10d formed on the surface of the base 10 in the above embodiments are abolished, and the entire surface is made uniform and flat. On the other hand, in the floating top plate 11 ', as shown in FIG.
d is formed. The air passage hole 11'd communicates with a hollow portion formed inside the floating top plate 11 ', and the hollow portion communicates with an external hose 11'b.
The hose 11'b is connected to an air compressor (air sending means) 11'a via a valve 11'c.
1'c is connected to the control device C. Edge 11
'B and the air reservoir 11'C are formed as in the first to third embodiments.

In the MRI apparatus having such a configuration, the compressed air blown out (or blown out) by the floating top plate 11 ′ rebounds on the surface of the base 10 and becomes a reaction force. 11 'itself is the base 1
A floating state appears on the 0 'plane.

In the fourth embodiment, when compared with the first embodiment, it is clear that the same operation and effect can be achieved except for the difference in the floating operation surface described above. It is. In other words, even in such a case, the medical treatment or examination of a doctor or the like can be functionally performed in parallel with the MRI imaging, and since there is no adverse effect of the motor, after the setting of the top plate 11 'is completed, MRI imaging can be performed immediately.

Incidentally, the couchtop movement constraint plate 12 and the couchtop movement constraint block 13 according to the second and third embodiments.
It is not necessary to particularly explain that the present invention can be applied in the same manner in the fourth embodiment.

In the first to third embodiments, the base 10 for blowing out the compressed air is provided separately, but the present invention is not limited to such a form. For example, in the imaging space H of the MRI apparatus main body G in FIG. 1, an air hole may be directly formed in the bottom surface Hb forming the space H, and the compressed air may be sent into the hole. That is,
The bottom surface Hb is directly configured to correspond to the base 10 described in each of the above embodiments. Even in such a case, it is clear that the same operation or effect as described above can be enjoyed.

The present invention also relates to the base 10 or 10 'and the floating top plate 11 or 1 in each of the above embodiments.
There is no intention to limit the shape or size of 1 '. For example, in the case of the second embodiment, it has been particularly described that the area of the floating top plate 11 is configured to be exactly 1/9 of that of the base 10. It is apparent that the present invention can be applied in various forms without being limited to the forms. Of course, the same applies to other embodiments other than the second embodiment.

Further, the plurality of air holes 10d in the first to third embodiments communicate with one cavity 10h in the base 10, and the plurality of air holes 10d pass through the one cavity 10h. Although the compressed air was ejected from 10d, the present invention is different from this.
The plurality of air holes 10d are divided into appropriate groups, and the group is provided with the valve 10c (or a set of the valve 10c and the air compressor 10a) for each of the groups, and a control device that controls the entire system. It is also conceivable to adopt a configuration in which C is provided, and to perform ON / OFF control relating to the ejection of air from a large number of air holes 10d on a group basis.

As a more specific embodiment in the above case, for example, an air hole 10 formed on the surface of the base 10 is used.
It is conceivable that the form of d is as shown in FIG. FIG. 8 is a cross-sectional view showing the vicinity of the surface of the base 10, and an air passage 10dR opening in the upper right direction in the figure.
And two types of air passage holes 10dL that open in the upper left direction. Each of these air holes 10dR and 10dL is connected to two cavities not communicating with each other at a lower part (not shown) in the figure, and these cavities are respectively air compressors 10aR and 10aL, valves 10cR and 10cL,
And the control device C.

According to such an embodiment, the air holes 10d
For R and 10 dL, it is possible to implement air conduction by different systems. And the air holes 10
If air is ejected from dR and air is not ejected from the air holes 10dL, the floating top plate 11
(Not shown in FIG. 8) moves to the right, and if the air ejection mode is reversed, the top plate 1
1 will move to the left. That is, in such a case, the control regarding the moving direction of the floating top plate 11 can be performed. Then, if such a top plate 11 can be automatically moved, it will be easily understood that it is convenient for continuous imaging of MRI or the like.

The concept of the above-described grouping of the air holes and the control of the conduction of the air to them is based on the air holes 11 'formed on the lower surface of the floating top plate 11' according to the fourth embodiment. Needless to say, the same can be applied to d.

[0052]

As described above, according to the nuclear magnetic resonance imaging apparatus of the present invention, the top plate on which the subject is placed can be held in a state of being levitated by aerodynamic force. Can be freely performed in any direction (that is, the direction of the subject can be freely changed). It can be implemented in a practical manner. This is particularly effective in a so-called “open MRI apparatus” having an opening in the imaging space.

Further, in the present invention, since a motor is not used as a power source of the tabletop, fluctuations (noise) of the electromagnetic field do not occur externally and adversely affect the image quality of the MRI photographed image. There is no. Therefore, it is not necessary to take a special measure such as performing the MRI imaging after waiting for the time decay of the noise as in the related art. That is, quick MRI imaging can be performed, and an MRI tomographic image with good image quality can always be obtained.

Furthermore, since there is no need to install a motor, the storage space for the motor, which was conventionally required, is not required, and if the base is appropriately sized,
The size of the MRI apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an MRI apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration near a base surface shown in FIG.

FIG. 3 is a perspective view of the configuration of the floating top plate shown in FIG.

FIG. 4 is a perspective view showing a configuration of a base on which a top board movement restricting plate according to a second embodiment of the present invention is installed.

FIG. 5 is a perspective view showing a configuration of a base on which a top board movement restraining block according to a third embodiment of the present invention is installed.

FIG. 6 is a schematic diagram illustrating an overall configuration of an MRI apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view of the configuration of the floating top plate shown in FIG.

FIG. 8 is a cross-sectional view showing a configuration in the vicinity of a base surface, which is a different form from FIG.

FIG. 9 is a schematic diagram showing the entire configuration of a conventional MRI apparatus.

[Explanation of symbols]

P Subject G MRI apparatus main body H Imaging space Ha Opening Hb Bottom (base) 1 Bed 1a Top 1b Bed main 2 Receiving coil (receiving means) 10, 10 'Base 11, 11' Floating top (top Board) 11A Surface 11B, 11'B Edge 11C, 11'C Air reservoir 10a, 10aR, 10aL, 11'a Air compressor (air sending means) 10b, 11'b Hose 10c, 10cR, 10cL, 11 ' c Valve 10d, 10dR, 10dL, 11'd Air hole 10e Leg 10h Cavity 12, 12a Top plate movement restricting plate (restraining means) 13, 13a Top plate moving restricting block (restraining means) S Stretcher C controller

Claims (8)

[Claims] 1. An apparatus comprising: excitation means for applying an excitation magnetic field to an object placed in a static magnetic field space; and gradient magnetic field applying means for applying a gradient magnetic field to the object. A nuclear magnetic resonance imaging apparatus, comprising: an apparatus main body having an imaging space portion; and a receiving unit for receiving an NMR signal detected from the object; and a tomographic image of the object introduced into the imaging space portion. A top plate on which the subject is directly mounted, a base for fixing the top plate at a predetermined position at the time of capturing the tomographic image, and a state in which the top plate is floated on the surface of the base by pneumatic force. A nuclear magnetic resonance imaging apparatus comprising: 2. The apparatus according to claim 1, wherein the air force is generated by blowing air out of the air through holes provided on the base surface connected to the air outgoing means. 2. The magnetic resonance imaging apparatus according to claim 1, wherein the pressure is the pressure at that time. 3. The air force is generated by blowing air out of the air through hole for the configuration of air sending means and a plurality of air through holes formed on the top plate surface connected to the air sending means. 2. The magnetic resonance imaging apparatus according to claim 1, wherein the pressure is the pressure at that time. 4. A valve is interposed between the air sending means and the air passage, and a control means for controlling a mode of jetting air from the air passage through opening and closing control of the valve is provided. The nuclear magnetic resonance imaging apparatus according to claim 2, wherein 5. The nuclear magnetic resonance imaging apparatus according to claim 2, wherein a restraint means for restricting a moving range of the top plate is provided on the base. 6. The nuclear magnetic resonance imaging apparatus according to claim 5, wherein said restraining means is a plate mounted on said base. 7. The nuclear magnetic resonance imaging apparatus according to claim 5, wherein the restraining means is a block installed on the base. 8. The imaging space unit has an opening that enables surgery or the like on the subject before, after, or during the imaging of the tomographic image. A nuclear magnetic resonance imaging apparatus according to any one of the preceding claims.