JP2004167104A - Magnetic shield room for magnetic resonance imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a magnetic shield room capable of improving the openness of wall surfaces therein by relaxing restriction on the size and install ation of an inspection window or a gateway. <P>SOLUTION: This magnetic shield room 1 is provided with a ceiling panel 2 made of a magnetic shield member, a floor panel 3 made of a magnetic shield member and a columnar yoke 4 for magnetically interconnecting the ceiling panel 2 and the floor panel 3, and the volume of the columnar yoke 4 is made equal with or more than the volume of the magnetic shields to be omitted from wall surfaces of the shield room. A magnetic field leaking from an MRI device 5 is leaked in the route of MRI device 5, ceiling panel 2, columnar yoke 4, floor panel 3 and MRI device 5, the leakage to the wall surfaces is suppressed, and magnetic shields to be used for the wall surfaces for reducing the leakage from the inside to the outside may be reduced. Further, mesh shields are available for shielding RF (radio frequency) noise from the outside of the shield room 1 to the inside, such that the disposing position or size of an examination window is not limited. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetically shielded room for a magnetic resonance imaging apparatus.
[0002]
[Prior art]
A magnetic resonance imaging apparatus (MRI apparatus) is an apparatus that forms a strong magnetic field in a magnetic field center space. When a strong magnetic field generated by the MRI apparatus leaks around the MRI apparatus, for example, a patient using a cardiac maker with a magnetic field strength of 0.5 mT or more, or a magnetic field strength of 0.1 mT or more is used. The display may be adversely affected.
[0003]
In addition, if a magnetic field enters the MRI apparatus from the outside, it becomes difficult to stably maintain a uniform magnetic field in the MRI apparatus.
[0004]
Therefore, it is necessary to install the MRI apparatus in a magnetically shielded room in order to avoid the influence of the magnetic field around the set position of the MRI apparatus and the influence of the external magnetic field. This magnetic shield room is described in Non-Patent Document 1, for example. This Non-Patent Document 1 relates to a magnetic shield room for reducing the influence of a magnetic field around an MRI apparatus, and a magnetic field analysis method is being studied.
[0005]
Here, a magnetic shield room for a magnetic resonance imaging apparatus according to the related art will be described with reference to FIG.
[0006]
FIG. 11A is a perspective view, and FIG. 11B is a plan view omitting a ceiling surface. As shown in FIGS. 11A and 11B, the ceiling surface, wall surface, and floor surface of the magnetically shielded room (hidden in FIG. 11A) include, for example, silicon steel plate, iron, and permalloy. A plate-shaped magnetic shielding member 102 made of, for example, is disposed.
[0007]
The plate-shaped magnetic shielding members 102 arranged on each surface are magnetically joined. As shown in FIG. 11B, the leakage magnetic field in the horizontal direction of the MRI apparatus 5 spreads as indicated by reference numeral 14. In FIG. 11, reference numeral 108 denotes an inspection window for an operator or the like to check the inside of the shield room, 109 denotes an entrance of the shield room, and 110 denotes a magnet entrance.
[0008]
[Non-patent document 1]
"Study of Magnetic Field Analysis Method for Shielded Room Design", Journal of the Japan Society of Applied Magnetics, Vol. 18, No. 5, 1994, pp. 934-939.
[Problems to be solved by the invention]
By the way, as shown in FIG. 11B, when an opening such as the inspection window 108 is provided in a portion of the wall surface of the magnetic shield room where the magnetic flux density of the leakage magnetic field from the MRI device 5 is high, the MRI device 5 The magnetic field MRI apparatus 5 from the outside spreads out of the magnetically shielded room. Therefore, the size of the inspection window 108 needs to be as small as possible. For example, when the shield room has a length of 5.5 to 6.0 m × width 4.5 to 5.0 m × height 2.5 to 3.0 m, the inspection window 108 is limited to about 1 m × 1 m. .
[0010]
Therefore, in the magnetic shield room in the related art, the size of the inspection window 108 and the entrance 109 is limited, and a subject (patient) in the shield room has a narrow impression in the shield room and a closed impression. Had become. Recently, open-type MRI apparatuses have been marketed and used. However, even if the MRI apparatuses themselves are open-type, if the shield room is closed, the subject will be impressed with a closed impression. May also be given.
[0011]
Further, it is not easy for the operator (radiologist) of the MRI apparatus to observe the state inside the magnetically shielded room, and the working efficiency is low.
[0012]
An object of the present invention is to realize a magnetic shield room capable of improving the openness of a wall surface by reducing restrictions on the size and installation position of an inspection window and an entrance.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
(1) In a magnetically shielded room for a magnetic resonance imaging apparatus accommodating a magnetic resonance imaging apparatus, a plate-shaped magnetic shielding member is arranged on two surfaces facing each other among outer surfaces forming a magnetically shielded room. A columnar yoke for magnetically connecting the plate-like magnetic shielding members arranged on the surface to each other is provided.
[0014]
(2) Preferably, in the above (1), the two surfaces facing each other are a ceiling surface and a floor surface.
[0015]
(3) Preferably, in the above (1), the two surfaces facing each other are wall surfaces.
[0016]
(4) Also, preferably, in the above (1), the columnar yoke is a part of a structure supporting a magnetically shielded room.
[0017]
(5) In a magnetically shielded room for a magnetic resonance imaging apparatus accommodating a magnetic resonance imaging apparatus, a plate-shaped magnetic shielding member is arranged on two surfaces facing each other among outer surfaces forming a magnetically shielded room. It has a columnar yoke that magnetically connects the plate-shaped magnetic shielding members arranged on the surfaces to each other, and an electromagnetic wave shield having a visually transparent property is formed on the other outer surface except for the two opposing surfaces. Have been.
[0018]
(6) In a magnetically shielded room for a magnetic resonance imaging apparatus accommodating a magnetic resonance imaging apparatus, a plate-shaped magnetic shielding member is disposed on two surfaces facing each other among outer surfaces forming a magnetically shielded room. A plurality of columnar yokes magnetically connect the plate-shaped magnetic shielding members arranged on the surface to each other, and at least one of the plurality of columnar yokes has a different cross-sectional area from other columnar yokes.
[0019]
(7) Also, preferably, in the above (1), the magnetic flux permeated into one plate-shaped magnetic shielding material penetrates into the other plate-shaped magnetic shielding material without leaking outside through a plurality of columnar yoke. In addition, it is desirable that the cross-sectional area of the columnar yoke is determined.
[0020]
(8) In a magnetically shielded room for a magnetic resonance imaging apparatus that houses a magnetic resonance imaging apparatus, a plate-shaped magnetic shielding member is disposed on two surfaces facing each other among outer surfaces forming a magnetically shielded room. A plurality of strip-shaped ferromagnetic bodies are magnetically connected to each other with the plate-shaped magnetic shielding members arranged on the surface and arranged with a gap therebetween.
[0021]
(9) Preferably, in the above (8), the gap between the plurality of strip-shaped ferromagnetic bodies is arranged so as to increase as the distance from the magnetic resonance imaging apparatus arranged in the shield room increases. You.
[0022]
(10) In a magnetically shielded room for a magnetic resonance imaging apparatus accommodating a magnetic resonance imaging apparatus, a plate-shaped magnetic shield is disposed on a plurality of outer surfaces of the magnetically shielded room, and at least one of the plurality of outer surfaces is provided. An internal monitoring window is formed on the side surface, and a plurality of strip-shaped ferromagnetic materials are arranged in the internal monitoring window.
[0023]
The leakage magnetic field from the magnetic resonance imaging I device becomes a magnetic resonance imaging device → two outer surfaces facing each other → a magnetic resonance imaging device. Leakage to other outer surfaces other than the two side surfaces is suppressed, and the inside used for the outer surface is used. It is possible to reduce the number of magnetic shielding materials for reducing leakage from the outside to the outside.
[0024]
Further, for shielding the RF noise from the outside to the inside of the shield room, a visually transparent material such as a mesh-shaped shielding material can be used, so that the arrangement position and size of the inspection window are limited. There is nothing.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view of a main configuration of a magnetic shield room 1 according to a first embodiment of the present invention and a plan view omitting a ceiling surface.
[0026]
The example shown in FIG. 1 is a magnetically shielded room in which a vertical magnetic field type MRI apparatus 5 (where the direction of the main magnetic field is a perpendicular direction) is housed.
[0027]
In addition, each of the six surfaces of the ceiling surface, floor surface, and wall surface is defined as an outer surface forming a magnetically shielded room.
[0028]
In the perpendicular magnetic field type MRI apparatus 5, most of the leaked magnetic flux blows out radially from above the MRI apparatus 5 (+ Z direction (toward the ceiling)), passes through the air, and passes below the MRI apparatus 5 (−Z From the direction (floor surface)) to the MRI apparatus 5.
[0029]
In the case where the perpendicular magnetic field type MRI apparatus 5 is stored, a plate-like magnetic material made of a ferromagnetic material such as a silicon steel plate, a general structural rolled material, or pure iron is provided on the ceiling surface 2 and the floor surface 3 of the magnetic shield room 1. Place a shield.
[0030]
Then, a columnar yoke 4 made of a ferromagnetic material such as a silicon steel plate, a rolled material having a general structure, or pure iron, which magnetically couples the ceiling surface 2 and the floor surface 3 which are plate-shaped magnetic shielding members, is arranged. The number of columnar yokes 4 depends on the magnitude of the leakage magnetic field from the MRI apparatus 5, but is preferably 2 to 4 in order to provide a sufficient opening in the wall portion of the magnetically shielded room (however, the columnar yoke is preferable). Iron may be one).
[0031]
In the example shown in FIG. 1, an example in which the number of columnar yokes 4 is two is shown. With this configuration, a magnetic circuit is formed by the plate-like magnetic shielding material of the ceiling surface 2 and the floor surface 3 and the columnar yoke 4, and the leakage magnetic field outside the magnetic shield room 1 is suppressed even if the wall surface is not part of the magnetic circuit. Will be done.
[0032]
FIG. 2 is a diagram showing a flow of the leakage magnetic flux from the MRI apparatus 5 arranged in the magnetic shield room 1 having the configuration of FIG.
In FIG. 2, the main magnetic field 6 from the MRI apparatus 5 is directed to the ceiling surface 2, and the flow 7 of the magnetic flux is from the ceiling surface 2 of the magnetic shield room 1 → the columnar yoke 4 → the floor surface 3 → the MRI apparatus 5. The thickness of the magnetic shielding material, the cross-sectional area of the columnar yoke 4, and the like are estimated by computer simulation or the like to an amount that can sufficiently capture the leakage magnetic field from the MRI apparatus 5.
[0033]
That is, when the magnetic shielding material to the outside is omitted on the three wall surfaces other than the wall of the magnet entrance 9 of the magnetic shield room 1, the magnetic flux permeating the upper or lower plate-like magnetic shielding material leaks to the outside. Instead, the cross-sectional area of the two columnar yokes 4 is determined so as to penetrate the other plate-shaped magnetic shielding material.
[0034]
In general, in a magnetic circuit, the shorter the path of the magnetic flux, the lower the magnetic resistance. Therefore, in order to capture the magnetic flux leaked from the MRI apparatus 5, the columnar yoke 4 must be installed in the four corners of the magnetic shield room. It is desirable to arrange at a corner close to.
[0035]
FIG. 1B shows the spread 14 of the leakage magnetic field in the horizontal direction of the MRI apparatus 5. In the example shown in FIG. 1B, compared to the example shown in FIG. 11B, the horizontal leakage magnetic field is attracted to the columnar yoke 4 side, and (In the longitudinal direction of the floor).
[0036]
This is because the magnetic shielding material used for the ceiling surface 2 and the floor surface 3 of the shield room can be omitted because the shape of the horizontal leakage magnetic field is shortened, and the amount of the magnetic shielding material used can be reduced. Become.
[0037]
FIG. 3 is a completed perspective view of a magnetic shield room 1 in which the magnetic shield shown in FIG. 1 is used. As shown in FIG. 3, the magnetic shielding member on the wall surface on which the inspection window 8 is formed can be omitted from a member for magnetic leakage from the inside to the outside, and is only for magnetic shielding from the outside to the inside. The member for magnetic shielding from the outside to the inside can be an electromagnetic wave shield that is visually transparent. Therefore, restrictions on the size and position of the inspection window (internal monitoring window) 8 are relaxed, and the size can be made sufficiently large for the operator to observe the inside.
[0038]
As described above, according to the first embodiment of the present invention, a ceiling plate 2 made of a magnetic shielding material, a floor plate 3 made of a magnetic shielding material, and a columnar shape magnetically connecting the ceiling plate 2 and the floor plate 3 The yoke 4 is provided, and the volume of the columnar yoke 4 is set to be larger than the volume of the magnetic shielding material to be omitted from the wall surface of the shield room.
[0039]
For this reason, the leakage magnetic field from the MRI apparatus 5 becomes MRI apparatus 5 → ceiling surface 2 → column-shaped yoke 4 → floor surface 3 → MRI apparatus 5, and the leakage to the wall surface is suppressed. The number of magnetic shielding materials for reducing leakage to the outside can be reduced.
[0040]
Further, since the shielding of the RF noise from the outside to the inside of the shield room 1 can be performed by using a mesh-like shielding material, there is no restriction on the arrangement position and size of the inspection window.
[0041]
Further, since the area where the leakage magnetic field spreads in the horizontal direction is shortened, the amount of the magnetic shielding material used can be reduced, and even if the cost associated with the installation of the columnar yoke 4 occurs, this cost increase is reduced. It is possible to absorb.
[0042]
Therefore, according to the first embodiment of the present invention, a magnetic shield room capable of improving the openness of the wall surface by reducing the size of the inspection window and the entrance and the restriction of the installation position without increasing the cost. Can be realized.
[0043]
FIG. 4 is a diagram illustrating a support structure of a magnetic shield room in which a plate-shaped shielding member and a columnar yoke according to the first embodiment of the present invention are disposed.
[0044]
In FIG. 4, in order to provide the inspection window 8, the entrance 10 and the like in the opening of the wall surface, a support pillar and a frame are formed by a non-magnetic structural member such as stainless steel. In the example shown in FIG. 4, an inspection window frame 51, an entrance / exit frame 52, and a carry-in door frame 53 are formed. In this case, the two columnar yokes 4 may also serve as a part of the support structure of the magnetic shield room 1.
[0045]
FIG. 5 is a diagram of a structure in which the inspection window 8, the magnet entrance 9, the entrance 10 and the like are provided in the first embodiment. In FIG. 5, the inspection window 8 is provided with transparent RF shields 11a and 11b such as a copper mesh.
[0046]
In addition, a transmissive RF shield may be provided on the doors of the magnet entrance 9 and the entrance 10. In this case, a transparent reinforcing material such as glass or resin is added to the RF shield material provided in the door portion so as not to be easily damaged.
[0047]
Further, in order to improve the openability, it is desirable to provide a transmissive RF shield in a frame portion other than the inspection window frame 51, the entrance / exit frame 52, and the carry-in door frame 53 shown in FIG.
[0048]
As described above, it is not necessary to dispose a plate-shaped magnetic shielding material on the wall surfaces of the magnetic shield room 1 other than the wall surface near the columnar yoke 4, so that the position and size of the inspection window 8 and the entrance 10 are limited. Is greatly reduced, and the use of a transmissive RF shield material makes it possible to form a magnetically shielded room having openness.
[0049]
FIG. 6 is a perspective view of a main configuration of a magnetic shield room according to a second embodiment of the present invention, and FIG. 7 is a diagram illustrating a flow of a leakage magnetic flux from the MRI apparatus 5 in the second embodiment.
[0050]
The second embodiment is an example in which the number of columnar yokes used in the magnetically shielded room 1 is four. The plate-like magnetic shielding members arranged on the ceiling surface 2 and the floor surface 3 and the four columnar yokes 41a, 41b, 42a, 42b are magnetically coupled.
[0051]
As shown in FIG. 6, the leakage magnetic field from the MRI apparatus 5 is a path from the MRI apparatus 5 → the ceiling surface 2 → the columnar yokes 41a and 41b → the floor surface 3 → the MRI device 5 and the MRI device 5 → the ceiling surface 2 → The route is from the columnar yoke 42a, 42b → the floor 3 → the MRI apparatus 5.
[0052]
By setting the number of the columnar yoke to four, the leakage magnetic field from the MRI apparatus 5 is appropriately distributed in the magnetic circuit formed by the plate-like magnetic shielding member and the columnar yoke. The shielding material and the columnar yoke can be used effectively.
[0053]
Further, the cross-sectional area of the two columnar yokes 42a, 42b located away from the MRI apparatus 5 may be smaller than the cross-sectional area of the two columnar yokes 41a, 41b adjacent to the MRI apparatus 5. In this case, the spread area of the leakage magnetic field in the horizontal direction is reduced as in the example shown in FIG.
[0054]
It is desirable that the cross-sectional areas and positions of the columnar yokes 41a, 41b, 42a, and 42b be optimized without interfering with the inspection window and the doorway so as not to impair the openness of the magnetic shield room 1.
[0055]
The total volume of the columnar yokes 41a, 41b, 42a, 42b is larger than the volume of the magnetic shielding material to be omitted from the wall surface of the shield room 1.
[0056]
According to the second embodiment of the present invention, the amount of the magnetic shielding material to be used for the wall surface can be reduced, so that the size of the inspection window and the entrance and the installation position are reduced, and the opening of the wall surface is reduced. A magnetically shielded room capable of improving the performance can be realized.
[0057]
FIG. 8 is a main configuration diagram of the magnetic shield room 1 according to the third embodiment of the present invention. The third embodiment is an example in which an MRI apparatus 54 in which a main magnetic field 61 is in a horizontal direction is arranged.
[0058]
In FIG. 8, a plate-like magnetic shielding member is arranged on two wall surfaces 21 and 31 facing the magnetic flux direction of the main magnetic field 61 from the MRI apparatus 54, among the wall surfaces constituting the magnetic shield room 1. Then, two columnar yokes 43 for magnetically coupling the plate-like magnetic shielding members on these two wall surfaces 21 and 31 are arranged on the ceiling side.
[0059]
In this case, if the openness is not impaired from the configuration of the magnetic shield room 1, a columnar yoke may be arranged on the wall surface side other than the two wall surfaces 21 and 31 where the magnetic shielding material is arranged.
[0060]
Further, the volume of the columnar yoke 43 is determined so as to be larger than the volume of the magnetic shielding material that will be used for the wall surface other than the wall surfaces 21 and 31 and the floor surface.
[0061]
In the third embodiment, the same effect as in the second embodiment can be obtained.
[0062]
FIG. 9 is a main configuration diagram of a magnetic shield room according to a fourth embodiment of the present invention. In the fourth embodiment, strip-shaped magnetic shielding members 61 arranged at intervals are used instead of using the columnar yoke.
[0063]
Note that the example shown in FIG. 9 is an example of a magnetically shielded room that houses a vertical magnetic field type MRI apparatus. For example, the strip-shaped magnetic shielding member 61 made of a ferromagnetic material such as a silicon steel plate magnetically couples the plate-shaped magnetic shielding members disposed on the ceiling surface 2 and the floor surface 3.
[0064]
With this configuration, the magnetic flux leaked from the + Z direction of the MRI apparatus 5 passes through a magnetic circuit including the plate-shaped magnetic shielding material on the ceiling surface 2, the strip-shaped magnetic shielding material 61, and the plate-shaped magnetic shielding material on the floor surface 3. , Return from the −Z direction of the MRI apparatus 5.
[0065]
Further, since the magnetic flux density is high in the area adjacent to the MRI apparatus 5, the arrangement intervals of the strip-shaped magnetic shielding members 61 are dense on the wall surface adjacent to the MRI apparatus 5, and are sparse at a place far from the MRI apparatus 5. It is arranged so that it becomes.
[0066]
With the above configuration, the amount of the magnetic shielding material used can be reduced.
[0067]
As described above, according to the fourth embodiment of the present invention, it is possible to realize a magnetic shield room capable of improving the openness of the wall surface.
[0068]
FIG. 10 is a main configuration diagram of a magnetic shield room according to a fifth embodiment of the present invention. The fifth embodiment is an example in which a wall surface 63 in which a strip-shaped magnetic shielding member 62 is disposed in an opening provided in the wall surface.
[0069]
Of the ceiling surface, floor surface, and wall surface of the magnetic shield room in which the plate-shaped magnetic shielding material is arranged, when an opening is provided for providing an inspection window or the like, a ferromagnetic material such as a silicon steel plate is provided in the opening. The plurality of strip-shaped magnetic shielding members 62 are arranged with a gap therebetween. With this configuration, it is possible to enlarge the opening such as the inspection window.
[0070]
As described above, according to the fifth embodiment of the present invention, a magnetically shielded room that can improve the openness of the wall surface can be realized.
[0071]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the size of an inspection window and an entrance can be reduced, and the magnetic shield room which can improve the openness of a wall surface can be implement | achieved by reducing restrictions.
[0072]
Thereby, it becomes easy for the operator of the MRI apparatus to observe the state in the magnetically shielded room, and the working efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main configuration of a magnetic shield room 1 according to a first embodiment of the present invention and a plan view in which a ceiling surface is omitted.
FIG. 2 is a diagram showing a flow of a leakage magnetic flux from an MRI apparatus arranged in a magnetic shield room having the configuration of FIG. 1;
FIG. 3 is a completed perspective view of a magnetic shield room using the magnetic shield material shown in FIG. 1;
FIG. 4 is a diagram illustrating a support structure of a magnetic shield room in which a plate-shaped shield and a columnar yoke according to the first embodiment of the present invention are disposed.
FIG. 5 is a diagram of a structure in which an inspection window, a magnet entrance, an entrance, and the like are provided in the first embodiment.
FIG. 6 is a perspective view of a main configuration of a magnetic shield room according to a second embodiment of the present invention.
FIG. 7 is a diagram showing a flow of a leakage magnetic flux from an MRI apparatus 5 according to the second embodiment.
FIG. 8 is a main configuration diagram of a magnetic shield room 1 according to a third embodiment of the present invention.
FIG. 9 is a main configuration diagram of a magnetic shield room according to a fourth embodiment of the present invention.
FIG. 10 is a main configuration diagram of a magnetic shield room according to a fifth embodiment of the present invention.
FIG. 11 is a main configuration diagram of a magnetic shield room in the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic shield room 2 Ceiling surface 3 Floor surface 4 Column yoke 5 MRI apparatus 6 Main magnetic field 7 Magnetic flux flow 8 Inspection window 9 Magnet entrance 10 Doorway 11a, 11b RF shield 14 Leakage magnetic field 21, 31 of MRI apparatus Plate magnetism Shielding materials 41a, 41b Column yoke 42a, 42b Column yoke 43 Beam yoke 51 Inspection window frame 52 Doorway frame 53 Carrying door frame 54 MRI devices 61, 62 Strip magnetic shield material 63 Magnetic shield wall

Claims (6)

In the magnetically shielded room for the magnetic resonance imaging apparatus that houses the magnetic resonance imaging apparatus,
A columnar yoke for arranging plate-shaped magnetic shielding members on two surfaces facing each other among outer surfaces forming a magnetic shield room and magnetically connecting the plate-shaped magnetic shielding members arranged on these two surfaces to each other. A magnetically shielded room for a magnetic resonance imaging apparatus, comprising: In the magnetically shielded room for the magnetic resonance imaging apparatus that houses the magnetic resonance imaging apparatus,
A columnar yoke for arranging plate-shaped magnetic shielding members on two surfaces facing each other among outer surfaces forming a magnetic shield room and magnetically connecting the plate-shaped magnetic shielding members arranged on these two surfaces to each other. A magnetically shielded room for a magnetic resonance imaging apparatus, wherein a visually transparent electromagnetic wave shield is formed on an outer surface other than the two surfaces facing each other. In the magnetically shielded room for the magnetic resonance imaging apparatus that houses the magnetic resonance imaging apparatus,
Among a plurality of outer surfaces forming a magnetic shield room, a plate-shaped magnetic shielding member is arranged on two surfaces facing each other, and a plurality of pillars magnetically connect the plate-shaped magnetic shielding members arranged on these two surfaces to each other. A magnetic shield room for a magnetic resonance imaging apparatus, comprising a yoke, wherein at least one of the columnar yokes has a different cross-sectional area from other columnar yokes. In the magnetically shielded room for the magnetic resonance imaging apparatus that houses the magnetic resonance imaging apparatus,
Of the outer surfaces forming the magnetic shield room, plate-shaped magnetic shielding members are arranged on two surfaces facing each other, and the plate-shaped magnetic shielding members arranged on these two surfaces are magnetically connected to each other, and a gap is formed between them. A magnetically shielded room for a magnetic resonance imaging apparatus, comprising: a plurality of strip-shaped ferromagnetic bodies arranged apart from each other. 5. A magnetic shield room for a magnetic resonance imaging apparatus accommodating the magnetic resonance imaging apparatus according to claim 4, wherein a gap between the plurality of strip-shaped ferromagnetic bodies is separated from the magnetic resonance imaging apparatus arranged in the shield room. A magnetically shielded room for a magnetic resonance imaging apparatus, wherein the magnetically shielded room is arranged so as to increase in size as the distance increases. In the magnetically shielded room for the magnetic resonance imaging apparatus that houses the magnetic resonance imaging apparatus,
A plurality of plate-shaped magnetic shielding members are arranged on a plurality of outer surfaces of the magnetic shield room, and an internal monitoring window is formed on at least one of the plurality of outer surfaces. A magnetically shielded room for a magnetic resonance imaging apparatus, wherein a ferromagnetic material is arranged.

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