JP2005270422A - Magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturized and lightweight magnetic resonance imaging apparatus to be easily combined with other examination devices with a very small burden applied to a subject. <P>SOLUTION: The magnetic resonance imaging apparatus comprises a gantry 10 whose side is open for generating a static magnetic field in the vertical direction to the space where the head of the subject is disposed, and an RF coil box 12 comprising a bobbin for storing the head of the subject, an RF coil wound around the bobbin and a box-shaped body to shield the inside, for applying a high-frequency magnetic field to the head of the subject and detecting a nuclear magnetic resonance signal emitted by the nuclear magnetic resonance of the atomic nucleus in the head of the subject. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic resonance imaging (MRI) apparatus, and more particularly to a small and lightweight magnetic resonance imaging apparatus that can be combined with another apparatus such as a magnetoencephalograph (MEG).

  MRI is a technology that visualizes the tomographic distribution of not only physical information in the living body but also molecular and chemical information using the nuclear magnetic resonance phenomenon, such as neurosurgery, neurology, orthopedics, etc. Has been widely spread in the clinical field. Unlike X-ray CT (Computer Tomography), MRI is a highly safe inspection technique that is non-invasive or minimally invasive, allowing children and normal subjects to undergo MRI examinations with peace of mind. It has become.

Further, in recent developments of MRI apparatuses, there is a trend toward higher magnetic fields and higher magnetic fields for the purpose of improving analysis performance such as improvement of resolution and shortening of imaging time.
Japanese Patent Application Laid-Open No. 62-26052 JP-A-8-50170 JP 11-189367 A

  However, the conventional MRI apparatus generally has a weight of several tons and requires a large space for installation. For this reason, it is difficult to receive examination diagnosis by MRI unless it is a medical institution having a dedicated examination room where an MRI apparatus is installed. In addition, with the recent trend of higher magnetic fields and higher magnetic fields, the size and weight of MRI apparatuses tend to increase.

  Further, in a conventional MRI apparatus, imaging is performed in a state where a subject is accommodated in, for example, a cylindrical gantry where a static magnetic field is formed. Since the subject is housed in the gantry with poor openness in this way, it is difficult to combine the MRI apparatus with another inspection apparatus such as MEG and simultaneously perform imaging with the MRI apparatus and inspection with another inspection apparatus. Met. Furthermore, a subject who undergoes a test diagnosis using a conventional MRI apparatus often feels claustrophobia because the patient is housed in a narrow gantry with poor openness. It put a heavy burden on the examiner.

  An object of the present invention is to provide a magnetic resonance imaging apparatus that is small and lightweight, can be easily combined with other inspection apparatuses, and has a very small burden on a subject.

  The object is to open the side and generate a static magnetic field in a direction perpendicular to the space in which the subject's head is arranged, a bobbin in which the subject's head is accommodated, An RF coil wound around the bobbin and a box-like body that houses the bobbin around which the RF coil is wound and shields the inside, and applies a high-frequency magnetic field to the head of the subject And a high-frequency magnetic field applying means and a nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of the nucleus in the head of the subject. Achieved.

  In the magnetic resonance imaging apparatus, the static magnetic field generating means includes a lower plate portion, an upper plate portion disposed above the lower plate portion so as to face the lower plate portion, and an end of the lower plate portion. The lower plate is provided between the upper plate portion and an end portion of the upper plate portion, and has a support plate portion that supports the upper plate portion on the lower plate portion. A static magnetic field may be generated in a space between the plate portion and the upper plate portion.

  In the magnetic resonance imaging apparatus, the bobbin and the box-like body may have transparency.

  The magnetic resonance imaging apparatus may further include a sleeping bag-like shield unit that accommodates a portion other than the subject's head and shields the inside.

  The magnetic resonance imaging apparatus may further include sheet-like shielding means that covers the entire subject and shields the subject.

  Further, the object is to generate a static magnetic field in a space in which the subject's head is arranged, a high-frequency magnetic field applying unit that applies a high-frequency magnetic field to the subject's head, A nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of a nucleus in the head of the subject, and a portion other than the head of the subject are accommodated and the inside is shielded This is achieved by a magnetic resonance imaging apparatus having a sleeping bag-like shield means.

  Further, the object is to generate a static magnetic field in a space in which the subject's head is arranged, a high-frequency magnetic field applying unit that applies a high-frequency magnetic field to the subject's head, A nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of a nucleus in the head of the subject; and the entire subject is covered to shield the subject. It is achieved by a magnetic resonance imaging apparatus having a sheet-like shield means.

  The magnetic resonance imaging apparatus may further include a tent-shaped shield unit that covers a space including the subject, the static magnetic field generation unit, the high-frequency magnetic field application unit, and the nuclear magnetic resonance signal detection unit. You may do it.

  Further, in the above magnetic resonance imaging apparatus, the subject is placed in a lying state and moved so that the head of the subject is placed in a space where the static magnetic field is generated by the static magnetic field generating means. You may make it further have a bed means to do.

  The magnetic resonance imaging apparatus may further include a magnetoencephalograph that measures a magnetic field generated in the subject's brain.

  As described above, according to the present invention, the static magnetic field generating means for generating a static magnetic field in a direction perpendicular to the space in which the side is opened and the subject's head is arranged, and the subject's head are accommodated. A bobbin that is wound, an RF coil wound around the bobbin, a bobbin around which the RF coil is wound, and a box-like body that shields the inside, and applies a high-frequency magnetic field to the head of the subject And a high-frequency magnetic field applying means and a nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of the nucleus in the head of the subject. Can be easily combined, and a magnetic resonance imaging apparatus with a very small burden on the subject can be provided.

  Further, according to the present invention, a static magnetic field generating means for generating a static magnetic field in a space in which the head of the subject is arranged, and a high-frequency magnetic field applying means for applying a high-frequency magnetic field to the subject's head , A nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of a nucleus in a subject's head, and a sleeping bag that contains a portion other than the subject's head and shields the inside Therefore, imaging is performed in a state where not only the head of the subject but also the part other than the head is shielded, and more accurate imaging can be realized.

  Further, according to the present invention, a static magnetic field generating means for generating a static magnetic field in a space in which the head of the subject is arranged, and a high-frequency magnetic field applying means for applying a high-frequency magnetic field to the subject's head , A nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of the nucleus in the subject's head, and a sheet shape covering the entire subject and shielding the subject Since it has a shielding means, imaging is performed in a state where the entire subject is shielded, and higher-accuracy imaging can be realized.

[First Embodiment]
A magnetic resonance imaging apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  First, the overall configuration of the magnetic resonance imaging apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram showing the overall configuration of the magnetic resonance imaging apparatus according to the present embodiment. FIG. 1A is a side view of the entire magnetic resonance imaging apparatus according to the present embodiment, and FIG. It is a front view of the whole magnetic resonance imaging apparatus.

  As shown in FIGS. 1A and 1B, the magnetic resonance imaging apparatus according to the present embodiment includes a static magnetic field magnet and a gradient magnetic field coil, and performs imaging of the head of a subject. A gantry 10 in which a magnetic field region is formed and a subject's head are accommodated, a high-frequency magnetic field is applied to the subject's head, and nuclear magnetic resonance of nuclei such as hydrogen nuclei in the subject's head. RF coil box 12 for detecting a nuclear magnetic resonance signal emitted by the radiography, a bed 14 on which a subject is placed in a supine state, and a shield tent for accommodating these and performing radio wave shielding and magnetic shielding 16.

  Hereinafter, each component constituting the magnetic resonance imaging apparatus according to the present embodiment will be described in detail.

  2 and 3 are schematic views showing the gantry in the magnetic resonance imaging apparatus according to the present embodiment, FIG. 2 (a) is a front view of the gantry, FIG. 2 (b) is a plan view of a lower plate portion of the gantry, 3A is a side view of the gantry, and FIG. 3B is a plan view of the upper plate portion of the gantry.

  As shown in each drawing, the gantry 10 includes a leg portion 18, a lower plate portion 20 provided on the leg portion 18, and an upper portion disposed above the lower plate portion 20 so as to face the lower plate portion 20. The plate portion 22 is provided between the end portion of the lower plate portion 20 and the end portion of the upper plate portion 22, and has a support plate portion 24 that supports the upper plate portion 22 on the lower plate portion 20. . As described above, the gantry 10 has a C-shape having an opening 25 in which a space between the lower plate 20 and the upper plate 22 on the side facing the support plate 24 is opened.

  In the lower plate portion 20 and the upper plate portion 22, static magnetic field magnets 26a and 26b are provided so as to face each other and generate a static magnetic field in the vertical direction. Rectifier plates 28a and 28b are provided on the opposing surfaces of the static magnetic field magnets 26a and 26b, respectively. Furthermore, a gradient magnetic field coil (not shown) for generating a gradient magnetic field is provided in the lower plate portion 20 and the upper plate portion 22.

  A lower yoke 30, a back yoke 32, and an upper yoke 34 are provided in the lower plate portion 20, the support plate portion 24, and the upper plate portion 22, respectively. The lower yoke 30, the back yoke 32, and the upper yoke 34 connect the static magnetic field magnet 26a provided in the lower plate portion 20 and the static magnetic field magnet 26b provided in the upper plate portion 22. As a result, a C-shaped magnetic field circuit that generates a static magnetic field in a direction perpendicular to the space between the lower plate portion 20 and the upper plate portion 22 is configured.

  A guide rail 36 that assists the movement of the bed 14 is provided in the vicinity of the bottom of the leg 18, and the direction from the opening 25 to the support plate 24 or the support plate 24 to the opening 25 is provided. The bed 14 moves in the direction of heading.

  The size of the gantry 10 is, for example, an open lateral width W of 800 mm, a length L from the support plate 24 to the opening 25 of 900 mm, and from the lower surface of the lower plate 20 to the upper surface of the upper plate 22. The height H is 600 mm. Further, as the static magnetic field magnets 28a and 28b, for example, permanent magnets having a magnetic field strength of 1.2T and a weight of 1.2 tons are used. As described above, the gantry 10 in the magnetic resonance imaging apparatus according to the present embodiment is much smaller and lighter than the gantry in the conventional magnetic resonance imaging apparatus.

  FIG. 4 is a schematic view showing an RF coil box in the magnetic resonance imaging apparatus according to the present embodiment, and FIG. 4A is an exploded perspective view showing a box-like body and a bobbin in the RF coil box. (B) is a perspective view showing an RF coil box in a state where a bobbin is accommodated in a box-shaped body.

  As shown in FIG. 4A, the RF coil box 12 includes a rectangular parallelepiped or cubic box 38 and a cylindrical bobbin 42 around which the RF coil 40 is wound. As shown in FIG. 4B, the bobbin 42 is accommodated in the box-shaped body 38 from a circular opening 44 provided on the side surface of the box-shaped body 38. One opening of the cylindrical bobbin 42 faces outward from a circular opening 44 provided on the side surface of the box-shaped body 38. At the time of imaging, the head of the subject is accommodated in the cylindrical bobbin 42 from the opening 44 provided on the side surface of the box-shaped body 38.

  The box-shaped body 38 is for shielding the inside, and an outer wall is formed of an insulating transparent resin such as an acrylic resin, and a shield material made of a mesh-like conductor foil is pasted on the inner surface thereof. Yes. As the shield material, for example, copper foil can be used. The outer wall is formed of a transparent resin, and the box-shaped body 38 has transparency through the mesh of the shield material. A connector 46 for supplying high-frequency power to the RF coil 40 and inputting a nuclear magnetic resonance signal detected by the RF coil 40 to a signal processing device (not shown) is provided on the outer wall of the box-shaped body 38. Is provided.

  The bobbin 42 is formed of an insulating transparent resin such as an acrylic resin, like the box-like body 38. The bobbin 42 is provided with an RF coil 40 for applying a high frequency magnetic field to the subject's head and detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of the nucleus in the subject's head. It is wound at intervals. The RF coil 40 is, for example, a solenoid coil in which electric wires having a diameter of 3 mm are wound around the bobbin 42 at intervals of 3 cm. The bobbin 42 is formed of a transparent resin, and the RF coil 40 is wound around the bobbin 42 at a predetermined interval, so that the bobbin 42 has transparency as with the box-shaped body 38. Yes. Both ends of the RF coil 40 are connected to a connector 46 provided on the side wall of the box-shaped body 38, high-frequency power is supplied to the RF coil 40 through the connector 46, and nuclear magnetism detected by the RF coil 40. A resonance signal is input to a signal processing device (not shown) via the connector 46.

  Thus, since the RF coil box 12 has transparency, the subject whose head is accommodated in the bobbin 42 of the RF coil box 12 visually recognizes the outside from the inside of the RF coil box 12. Can be done. Therefore, the subject does not feel a feeling of closing, a feeling of pressure, or a fear during imaging, and the psychological burden on the subject is extremely small. Moreover, since the RF coil box 12 has transparency, the operator of the apparatus can visually recognize the inside from the outside of the RF coil box 12. Therefore, the facial expression of the subject whose head is housed in the RF coil box 12 can be confirmed, and the state of the subject at the time of imaging can be grasped.

  The bed 14 is provided with casters at its legs so that it can move in the horizontal direction. The subject is placed on the bed 14 in a state where the subject lies with his head facing the gantry 10 side. Note that the bed 14 does not necessarily have to be moved as a whole by a caster or the like. For example, the bed 14 may have a mechanism in which only the top plate portion on which the subject lies is slid to the gantry 10 side. Good.

  The shield tent 16 is for shielding the inside as a radio wave shield for blocking external radio waves and a magnetic shield for suppressing a leakage magnetic field, and includes a space including the subject, the gantry 10, the RF coil box 12, and the bed 14. It covers the entire periphery and top and bottom surfaces of the. The sheet base of the shield tent 16 has a transparency, for example, in which a mesh-like conductor is attached or knitted to a resin sheet, a woven or knitted fabric or the like. Therefore, the examinee can visually recognize the inside from the inside of the shielding tent 16 and the operator of the apparatus can visually recognize the inside from the outside of the shielding tent 16. Therefore, the subject 48 imaged inside does not feel a sense of closeness, pressure, or fear. Further, by using the shielding tent 16, the magnetic imaging apparatus according to the present embodiment does not need to shield the examination room itself in which the apparatus is installed as in the prior art. Since it is not necessary to install the apparatus in a dedicated examination room, it is possible to change the installation place flexibly as necessary.

  FIG. 5 is a schematic view showing a state in which the subject on the bed 14 is imaged in the magnetic resonance imaging apparatus according to the present embodiment. In FIG. 5, the shielding tent 16 is omitted.

  As shown in FIG. 5A, the subject 48 is placed on the bed 14 in a supine state, for example.

  As shown in FIG. 5 (b), the bed 14 on which the subject 48 is placed is supported from the opening 25 side of the gantry 10 along the guide 36 provided on the leg portion 18 of the gantry 10. The head of the subject 48 moves in the direction toward the side until it is positioned between the lower plate portion 20 and the upper plate portion 22 of the gantry 10.

  The head of the subject 48 disposed between the lower plate portion 20 and the upper plate portion 22 of the gantry 10 is accommodated in the bobbin 42 of the RF coil box 12 as shown in FIG. . Before placing the head of the subject 48 between the lower plate portion 20 and the upper plate portion 22 of the gantry 10, the head of the subject 48 is previously placed on the bobbin of the RF coil box 12 on the bed 14. It may be accommodated in 42.

  In the state shown in FIG. 5 (b), a predetermined static magnetic field and gradient magnetic field are formed between the lower plate portion 20 and the upper plate portion 22 of the gantry 10, and the subject is inspected by the RF coil 40 of the RF coil box 12. A predetermined high frequency magnetic field is applied to the 48 heads. A nuclear magnetic resonance signal emitted by nuclear magnetic resonance of the nucleus in the head of the subject 48 is detected by the RF coil 40 of the RF coil box 12.

  The nuclear magnetic resonance signal detected by the RF coil 40 of the RF coil box 12 is sent to a signal processing device (not shown). In a signal processing device (not shown), predetermined signal processing is performed, and an image based on a nuclear magnetic resonance signal is formed.

  Thus, the head of the subject 48 is imaged by the magnetic resonance imaging apparatus according to the present embodiment.

  The magnetic resonance imaging apparatus according to the present embodiment includes a lower plate portion 20, an upper plate portion 22 disposed above the lower plate portion 20 so as to face the lower plate portion 20, and an end portion and an upper portion of the lower plate portion 20. Mainly, it has a C-shaped gantry 10 provided between the end portion of the plate portion 22 and a support plate portion 24 that supports the upper plate portion 22 on the lower plate portion 20. There are features.

  In the magnetic resonance imaging apparatus according to the present embodiment, since the gantry 10 has a C-shape, the gantry 10 itself can be made small and light. Therefore, the entire magnetic resonance imaging apparatus can be made small and light. For this reason, when installing the magnetic resonance imaging apparatus according to the present embodiment, it is not necessary to prepare a dedicated installation place, and the installation place can be selected with a high degree of freedom. Also, relocation can be performed easily.

  In the magnetic resonance imaging apparatus according to the present embodiment, the sides other than the direction in which the support plate portion 24 is provided in the gantry 10 are opened. Since the head of the subject 48 is imaged in the space between the lower plate portion 20 and the upper plate portion 22 of the gantry 10 having a very high openness, the subject 48 feels closed, There is no feeling of pressure or fear. In addition, since the openness of the space in which the image is taken is very high, it is easy to access the head of the subject 48 where the image is taken. Accordingly, simultaneously with imaging, the head can be inspected by another inspection device, such as measuring a weak magnetic field generated in the brain with the neural activity of the brain by MEG. Alternatively, the head can be treated at the same time as imaging, such as a surgical treatment such as a craniotomy.

  Furthermore, the magnetic resonance imaging apparatus according to the present embodiment is provided with a shield tent 16 that covers the entire periphery and upper and lower surfaces of the space including the subject 48, the gantry 10, the RF coil box 12, and the bed 14. Therefore, it is not necessary to shield the examination room itself where the apparatus is installed. Thus, since the magnetic resonance imaging apparatus according to the present embodiment does not need to be installed in a dedicated examination room, the installation location can be flexibly changed as necessary.

  Thus, according to the present embodiment, a magnetic resonance imaging apparatus that is small and lightweight, can be easily combined with other inspection apparatuses, and has an extremely low burden on the subject can be provided.

[Second Embodiment]
A magnetic resonance imaging apparatus according to a second embodiment of the present invention will be described with reference to FIG. The same components as those of the magnetic resonance imaging apparatus according to the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  The magnetic resonance imaging apparatus according to the present embodiment is made of an opaque or low-transparency insulating material instead of the RF coil box 12 in the magnetic resonance imaging apparatus according to the first embodiment, and has a box-like body formed with a plurality of small holes. And having an RF coil box with a bobbin.

  6A and 6B are schematic views showing the RF coil box in the magnetic resonance imaging apparatus according to the present embodiment. FIG. 6A is a perspective view showing a state in which the box-shaped body and the bobbin are disassembled, and FIG. It is a perspective view which shows the state which accommodated the bobbin in the shape body.

  Similar to the RF coil box 12 in the magnetic resonance imaging apparatus according to the first embodiment, the RF coil box 50 has a rectangular parallelepiped or cubic box-like body 52 and the RF coil 40 wound as shown in FIG. The cylindrical bobbin 54 is formed. The bobbin 54 is accommodated in the box-shaped body 52 through a circular opening 56 provided on the side surface of the box-shaped body 52 as shown in FIG. One opening of the cylindrical bobbin 54 faces outward from a circular opening 56 provided on the side surface of the box-shaped body 52. At the time of imaging, the subject's head is accommodated in the cylindrical bobbin 54 from the opening 56 on the side surface of the box-shaped body 52.

  The box-like body 52 is for shielding the inside thereof, an outer wall is formed of an insulating resin having an opaque or low transparency, and a shield material made of a mesh-like conductor foil is provided on the inner surface thereof. . As the shield material, for example, copper foil can be used. Further, a plurality of small holes are formed in the outer wall of the box-shaped body 52. The outer wall is formed of an opaque or low-transparency resin in which a plurality of small holes are formed, and the box-shaped body 52 has transparency through the mesh of the shield material. A connector 46 is provided on the outer wall of the box-like body 52.

  The bobbin 54 is formed of an opaque or low-transparency insulating resin, like the box-like body 52. The bobbin 54 has a plurality of small holes. The RF coil 40 is wound around such a bobbin 54. The bobbin 54 is formed of an opaque or low-transparency resin in which a plurality of small holes are formed, and the RF coil 40 is wound around the bobbin 54 at a predetermined interval. Like 52, it has transparency.

  Also in the magnetic resonance imaging apparatus according to the present embodiment, the RF coil box 50 is made transparent by the box-like body 52 and the bobbin 54 made of an opaque or low-transparency insulating material and having a plurality of small holes. Therefore, as in the case of the magnetic resonance imaging apparatus according to the first embodiment, the subject 48 whose head is housed in the bobbin 54 of the RF coil box 50 has a feeling of closing, feeling of pressure, feeling of fear. The psychological burden on the subject 48 can be made extremely small.

  Furthermore, since the small holes are formed in the box-like body 52 and the bobbin 54, high air permeability is ensured, and the breathing feeling felt by the subject 48 whose head is accommodated in the bobbin 54 can be reduced. it can.

  In the present embodiment, the small holes are formed in the box-shaped body 52 and the bobbin 54, but the box-shaped body 52 and the bobbin 54 may be made of a mesh-like resin. However, since the load by the RF coil 40 acts on the bobbin 54 at the time of imaging, it is necessary to have strength that can withstand this load.

[Third Embodiment]
A magnetic resonance imaging apparatus according to a third embodiment of the present invention will be described with reference to FIG. The same components as those of the magnetic resonance imaging apparatus according to the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  The magnetic resonance imaging apparatus according to the present embodiment is mainly characterized in that the magnetic resonance imaging apparatus according to the first embodiment has a shielding sleeping bag that shields portions other than the head of the subject.

  FIG. 7 is a schematic diagram showing a shielding sleeping bag in the magnetic resonance imaging apparatus according to the present embodiment, and FIG. 7A is a schematic diagram showing a state in which a subject is housed in the RF coil box and the shielding sleeping bag. FIG. 7B is an enlarged sectional view showing a sectional structure of the material of the sleeping bag for shielding.

  As shown in FIG. 7 (a), the subject 48 is placed on the bed 14 in a state where a portion other than the head is housed in a shielding sleeping bag 58 that blocks external radio waves. The head of the subject 48 is accommodated in the RF coil box 12 as in the magnetic resonance imaging apparatus according to the first embodiment.

  The material of the sleeping bag 58 for shielding is, for example, as shown in FIG. 7B, from an inner cloth 60, an outer cloth 62, and a conductor mesh 64 provided between the inner cloth 60 and the outer cloth 62. It has the laminated structure which becomes. Since the conductor mesh 64 is not directly touched by the inner cloth 60 with respect to the subject 48, discomfort felt by the subject is suppressed.

  A flange 66 that is electrically connected to the conductor mesh 64 is provided at the entrance of the shielding sleeping bag 58. A flange 68 is provided on the outer wall of the RF coil box 12 where the opening 44 is provided, and is electrically connected to a shield material affixed to the inner surface of the box-shaped body 38. By means of these flanges 66, 68, a shielding sleeping bag 58 in which a portion other than the head of the subject 48 is accommodated and an RF coil box 12 in which the head of the subject 48 is accommodated The conductor mesh 64 of the shield sleeping bag 58 and the shield material of the box-shaped body 38 of the RF coil box 12 are electrically connected in the vicinity of the neck.

  Thus, in the magnetic resonance imaging apparatus according to the present embodiment, not only the head of the subject 48 but also the part other than the head is shielded by the shielding sleeping bag 58, the magnetic resonance imaging apparatus according to the first embodiment Similarly, the head of the subject 48 is imaged.

  Thus, according to the present embodiment, imaging is performed in a state where not only the head of the subject 48 but also the part other than the head is shielded by the shielding sleeping bag 58 that blocks external radio waves. High-accuracy imaging can be realized.

  In the present embodiment, the case where the shielding sleeping bag 58 is used in the magnetic resonance imaging apparatus according to the first embodiment has been described. However, the shielding sleeping bag 58 is also used in the magnetic resonance imaging apparatus according to the second embodiment as described above. Can be used. Furthermore, not only the magnetic resonance imaging apparatus according to the first embodiment and the second embodiment but also the shielding sleeping bag 58 can be used for imaging the head of a subject using a conventional magnetic resonance imaging apparatus.

[Fourth Embodiment]
A magnetic resonance imaging apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. Components similar to those of the magnetic resonance imaging apparatus according to the first embodiment shown in FIGS. 1 to 5 and the third embodiment shown in FIG. 7 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  The magnetic resonance imaging apparatus according to the present embodiment is mainly characterized in that in the magnetic resonance imaging apparatus according to the first embodiment, the RF coil box 12 has a shielding sheet for shielding the entire subject whose head is accommodated. There is.

  FIG. 8 is a schematic view showing a shielding sheet in the magnetic resonance imaging apparatus according to the present embodiment.

  As shown in the figure, the subject 48 is placed on the bed 14 in a supine state via the conductive plate 70. A rug 72 such as a mattress is laid between the conductive plate 70 and the body portion of the subject 48. The head of the subject 48 is accommodated in the RF coil box 12 as in the magnetic resonance imaging apparatus according to the first embodiment. On the subject 48 whose head is housed in the RF coil box 12, a shielding sheet 74 for blocking external radio waves is covered.

  The material of the shielding sheet is the same as the material of the sleeping bag 58 for shielding in the magnetic resonance imaging apparatus according to the third embodiment shown in FIG. 7B, for example, the inner cloth 60, the outer cloth 62, and the inner cloth 60. And a conductive mesh 64 provided between the outer cloth 62 and the outer fabric 62. Since the conductor mesh 64 is not directly touched by the inner cloth 60 with respect to the subject 48, discomfort felt by the subject 48 is suppressed.

  A fixing jig 76 that is electrically connected to the conductor mesh 64 is provided on the outer edge of the shield sheet 74. With this fixing jig 76, the shield sheet 74 is fixed to the conductive plate 70 in a state where the whole of the subject 48 whose head is housed in the RF coil box 12 is covered. The conductor mesh 64 and the conductive plate 70 are electrically connected.

  Thus, in the magnetic resonance imaging apparatus according to the present embodiment, the whole of the subject 48 whose head is accommodated in the RF coil box 12 is shielded by the shielding sheet 74, and the magnetic resonance imaging according to the first embodiment. The head of the subject 48 is imaged in the same manner as the apparatus.

  Thus, according to the present embodiment, imaging is performed in a state where the entire subject 48 whose head is housed in the RF coil box 12 is shielded by the shielding sheet 74 that blocks external radio waves. Therefore, more accurate imaging can be realized.

  In the present embodiment, the case where the shield sheet 74 is used in the magnetic resonance imaging apparatus according to the first embodiment has been described. However, in the magnetic resonance imaging apparatus according to the second embodiment, the shield sheet 74 is used in the same manner as described above. Can be used. Furthermore, not only the magnetic resonance imaging apparatus according to the first embodiment and the second embodiment but also the shield sheet 74 can be used for imaging the head of a subject using a conventional magnetic resonance imaging apparatus.

[Modified Embodiment]
The present invention is not limited to the above embodiment, and various modifications can be made.

  For example, in the above-described embodiment, the case where the subject 48 is placed on the bed 14 in a state where the subject 48 is lying upside down has been described, but the orientation of the subject 48 placed on the bed 14 in the state of lying down is supine. The present invention is not limited to this, and can be changed as appropriate according to the direction and position of the imaging cross section. For example, the subject 48 may be placed on the bed 14 with the face lying on its side. Alternatively, it may be placed on the bed 14 in a face-down state.

  Moreover, although the said embodiment demonstrated the case where RF coil box 12 and 50 was a rectangular parallelepiped or a cube-shaped thing, the shape of RF coil box 12 and 50 is not limited to these. The RF coil boxes 12 and 50 may have any shape as long as the bobbins 42 and 54 can be accommodated therein.

  Moreover, although the said embodiment demonstrated the case where a test subject's head was accommodated in the cylindrical bobbins 42 and 54, the shape of the bobbins 42 and 54 is not limited to a cylindrical shape. The bobbins 42 and 54 may have any shape as long as the RF coil 40 can be wound around the bobbins 42 and 54 and the head of the subject can be accommodated inside the bobbins 42 and 54.

  Moreover, in the said embodiment, the box-shaped body 38 and the bobbin 42 which comprise the RF coil box 12 shall consist of transparent resin, or the box-shaped body 52 and the bobbin 54 which comprise the RF coil box 50 are made into several small holes. However, the material of the box-shaped body and the bobbin constituting the RF coil box is not limited to these. The material of the box-shaped body and bobbin may be any material that has a transparency that allows the subject whose head is accommodated in the RF coil box to be visible from the inside, for example, a mesh-like insulating material. Various materials such as a conductive resin can be used.

  Moreover, although the said embodiment demonstrated the case where the subject's head was imaged, this invention is applicable also to imaging of various site | parts other than a head. In this case, the size and shape of the RF coil boxes 12 and 50 may be changed as appropriate according to the imaging region of the subject.

  In the above embodiment, the case where the magnetic resonance imaging apparatus according to the present invention has the shield tent 16 has been described. However, when the shield is installed in a dedicated examination room, there is no shield tent 16. Also good.

  In the above-described embodiment, the case of the single coil system in which one RF coil 40 is also used to apply a high-frequency magnetic field and detect a nuclear magnetic resonance signal has been described. Detection may be performed using separate RF coils.

  Moreover, although the said embodiment demonstrated the case where a solenoid coil was used as the RF coil 40, a saddle coil etc. can also be used as the RF coil 40 other than a solenoid coil.

  In the above embodiment, the configuration of the magnetic resonance imaging apparatus alone has been described. However, a configuration in which other inspection apparatuses such as MEG are appropriately combined may be used.

1 is a schematic diagram showing an overall configuration of a magnetic resonance imaging apparatus according to a first embodiment of the present invention. It is the schematic (the 1) which shows the gantry in the magnetic resonance imaging apparatus by 1st Embodiment of this invention. It is the schematic (the 2) which shows the gantry in the magnetic resonance imaging apparatus by 1st Embodiment of this invention. It is the schematic which shows the RF coil box in the magnetic resonance imaging apparatus by 1st Embodiment of this invention. It is the schematic which shows a mode that the subject on a bed is imaged in the magnetic resonance imaging apparatus by 1st Embodiment of this invention. It is the schematic which shows the RF coil box in the magnetic resonance imaging apparatus by 2nd Embodiment of this invention. It is the schematic which shows the sleeping bag for shielding in the magnetic resonance imaging apparatus by 3rd Embodiment of this invention. It is the schematic which shows the sheet | seat for shielding in the magnetic resonance imaging apparatus by 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Gantry 12 ... RF coil box 14 ... Bed 16 ... Shield tent 18 ... Leg part 20 ... Lower plate part 22 ... Upper plate part 24 ... Supporting plate part 25 ... Opening part 26 ... Static magnetic field magnet 28a, 28b ... Rectification Plate 30 ... Lower yoke 32 ... Back yoke 34 ... Upper yoke 36 ... Guide rail 38 ... Box body 40 ... RF coil 42 ... Bobbin 44 ... Opening 46 ... Connector 48 ... Subject 50 ... RF coil box 52 ... Box shape Body 54 ... Bobbin 56 ... Opening 58 ... Shield sleeping bag 60 ... Inner cloth 62 ... Outer cloth 64 ... Conductor mesh 66 ... Flange 68 ... Flange 70 ... Conductive plate 72 ... Rug 74 ... Shield sheet 76 ... Fixed jig

Claims (10)

A static magnetic field generating means for generating a static magnetic field in a direction perpendicular to a space in which the side is opened and the head of the subject is disposed;
A bobbin that accommodates the head of the subject; an RF coil wound around the bobbin; and a box-like body that houses the bobbin around which the RF coil is wound and shields the inside thereof, A high-frequency magnetic field applying means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of a nucleus in the subject's head and applying a high-frequency magnetic field to the subject's head and detecting a nuclear magnetic resonance signal And a magnetic resonance imaging apparatus. The magnetic resonance imaging apparatus according to claim 1.
The static magnetic field generating means includes a lower plate portion, an upper plate portion disposed above the lower plate portion so as to face the lower plate portion, an end portion of the lower plate portion, and an end of the upper plate portion. And a support plate portion that supports the upper plate portion on the lower plate portion, and the lower plate portion and the upper plate portion on which the head of the subject is disposed A magnetic resonance imaging apparatus characterized by generating a static magnetic field in the space between the two. The magnetic resonance imaging apparatus according to claim 1 or 2,
The bobbin and the box-shaped body have transparency, The magnetic resonance imaging apparatus characterized by the above-mentioned. The magnetic resonance imaging apparatus according to any one of claims 1 to 3,
A magnetic resonance imaging apparatus further comprising sleeping bag-like shield means for accommodating a portion other than the head of the subject and shielding the interior. The magnetic resonance imaging apparatus according to any one of claims 1 to 3,
A magnetic resonance imaging apparatus further comprising sheet-shaped shielding means that covers the entire subject and shields the subject. A static magnetic field generating means for generating a static magnetic field in a space in which the head of the subject is arranged;
A high-frequency magnetic field applying means for applying a high-frequency magnetic field to the head of the subject;
A nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of a nucleus in the head of the subject;
A magnetic resonance imaging apparatus comprising: a sleeping bag-like shield means for accommodating a portion other than the head of the subject and shielding the inside. A static magnetic field generating means for generating a static magnetic field in a space in which the head of the subject is arranged;
A high-frequency magnetic field applying means for applying a high-frequency magnetic field to the head of the subject;
A nuclear magnetic resonance signal detecting means for detecting a nuclear magnetic resonance signal emitted by nuclear magnetic resonance of a nucleus in the head of the subject;
A magnetic resonance imaging apparatus comprising: sheet-like shielding means that covers the entire subject and shields the subject. The magnetic resonance imaging apparatus according to any one of claims 1 to 7,
A magnetic resonance imaging apparatus further comprising tent-shaped shield means for covering a space including the subject, the static magnetic field generation means, the high-frequency magnetic field application means, and the nuclear magnetic resonance signal detection means. The magnetic resonance imaging apparatus according to any one of claims 1 to 8,
The apparatus further comprises bed means that is placed in a state where the subject is sleeping and moves so as to place the head of the subject in a space where a static magnetic field is generated by the static magnetic field generation means. Magnetic resonance imaging device. The magnetic resonance imaging apparatus according to any one of claims 1 to 9,
A magnetic resonance imaging apparatus further comprising a magnetoencephalograph for measuring a magnetic field generated in the brain of the subject.

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