JP2001198104A - Coil structure of mri device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely exhibit function by suitably arranging a shield for preventing electric and magnetic interference between a WB coil and an inclined magnetic field coil even in a silencing type MRI device as well as to maintain S/N at receiving time and generating efficiency of a spin exciting magnetic field in an excellent value by minimizing reduction in efficiency of the WB coil caused by arranging the shield. SOLUTION: The inclined magnetic field coil 13 is arranged in a vacuum sealing vessel 12, and the WB coil 17 is arranged on the vessel outside of an inner peripheral side wall body 12B in the vessel 12. A shield body 16 for restraining magnetic interference between the inclined magnetic field coil 13 and the WB coil 17 is arranged between the inner peripheral side wall body 12B in the vessel and the inclined magnetic field coil 13. The shield body 16 is stuck to, for example, an inner peripheral surface of the inclined magnetic field coil 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil structure of a magnetic resonance imaging apparatus (hereinafter, referred to as "MRI apparatus"), and in particular, controlled to a pressure substantially lower than the atmosphere for the purpose of reducing noise during diagnosis. The present invention relates to an arrangement structure of a shield body for suppressing magnetic interference between a gradient magnetic field coil and an RF coil in an MRI apparatus in which a gradient magnetic field coil is sealed in a container.

[0002]

2. Description of the Related Art An MRI apparatus requires an RF coil for applying an RF magnetic field for spin excitation to an object or receiving an MR signal such as an echo induced in the object.

One of the RF coils is a whole body RF coil used for whole body radiography.
Coil; hereinafter, referred to as a WB coil). The WB coil is usually located at a position closer to the patient than other coils in the magnet mount. This WB coil has
Generates an RF magnetic field for spin excitation and receives an MR signal generated in the subject. A so-called dual-purpose coil, or generates only an RF magnetic field for spin excitation, and receives signals using other surface coils. There is a so-called transmission-only type of coil.

[0004] In most MRI apparatuses, a gradient magnetic field coil for generating a gradient magnetic field is arranged on the outer peripheral side of the WB coil. Using this gradient magnetic field coil, a magnetic field whose magnetic field intensity changes linearly according to the position is applied to the subject with high efficiency. For this reason, the conductor of the gradient magnetic field coil is usually wound with a larger number of turns than the WB coil.

[0005] Furthermore, as another requirement, the gradient magnetic field coil needs to perform high-efficiency switching in a frequency range much lower than the resonance frequency used in MRI. That is, energy loss that cannot be ignored in the resonance frequency range is likely to occur.

Therefore, for the WB coil (which resonates in a circuit in accordance with the resonance frequency), the electric loss due to the arranged gradient magnetic field coil becomes a load that cannot be ignored, and lowers the generation efficiency of the excitation RF magnetic field. This leads to a decrease in reception sensitivity.

In order to suppress magnetic interference between the WB coil and the gradient coil, a shield (copper foil) having a sufficiently small loss with respect to the resonance frequency is provided between the two as shown schematically in FIG. (For example, U.S. Pat. No. 5,367,261).
No.). This shield is usually grounded.

On the other hand, it is known that when the shield is arranged in this way, the reception sensitivity of the WB coil is reduced due to the shield (for example, the document “A Te”).
chnique of Double Resonan
t Operation of F and H Qu
addrture Birdcage Coils "M
acoustic Resonance in Medi
cine 19, 180-185 (1991)).
However, since the loss due to the mutual interference between the WB coil and the gradient coil when the shield is not disposed is greater than the loss due to the WB coil due to the shield, most MRI apparatuses have the shield disposed as described above. are doing. Note that, as can be seen from the above-mentioned literature, the greater the distance between the shield and the WB coil, the more the decrease in the efficiency of the WB coil can be suppressed.

[0009] The shield itself is thus used as a suboptimal measure, but the shield can be easily fixed at a potential substantially different from that of the WB coil. Utilizing this, an electric switch is provided between the WB coil and the shield, and so-called "detune" in which the resonance frequency of the WB coil is shifted by controlling the opening and closing of this switch is known (for example, in the United States). Patent No. 5,053
711). Further, by fixing the shield to, for example, zero potential, it is also used as a zero potential surface of the WB coil and a circuit up to the WB coil.

[0010]

By the way, the gradient magnetic field coil mechanically vibrates due to the electromagnetic force acting when it is driven, and is a source of sound (noise). In order to reduce this sound, there is also known a structure in which a gradient magnetic field coil is sealed and arranged in a cylindrical container whose internal pressure is controlled to a value substantially lower than the atmospheric pressure to reduce air propagation of sound. (See, for example, US Pat. No. 5,793,210).

However, a suitable and specific proposal has not yet been made for the case where the above-mentioned shield is arranged in such a noise reduction type MRI apparatus.

Therefore, if the conventional shield arrangement method is applied directly to this MRI apparatus of the silent type,
It is assumed that the configuration is as follows. First, WB
The coil is arranged on the outer side of the inner peripheral side wall of the container, that is, on the inner peripheral surface side of the container, from the viewpoint of improving the S / N by arranging the coil as close to the subject as possible. The shield is WB
Since it is also used as a fixed potential for the coil and as a zero potential for a switch or a transmission system, it must be disposed outside the inner peripheral side wall of the container, that is, on the inner peripheral side of the container. This is because, in order to use the shield for these purposes, it is more convenient to make an electrical connection with the shield at a position close to the WB coil. As a result, when viewed from the subject in the magnet radial direction, the WB coil, the shield, the container (the gradient magnetic field coil is enclosed), and the static magnetic field magnet are arranged in this order.

However, when the shield is disposed outside the inner peripheral side wall of the container, that is, on the inner peripheral side of the container, the WB is required to have the same size in the radial direction of the entire magnet mount. The distance between the coil and the shield in the radial direction of the magnet is simply the thickness of the container (total thickness of the inner peripheral side wall and the outer peripheral side wall) as compared with the conventional structure using no container.
It becomes narrow by the amount of As described above, this causes an increase in the loss of the WB coil, which may result in a serious deterioration in function.

The present invention has been made in view of the above-mentioned prior art, and is a shield for preventing electrical and magnetic interference between a WB coil and a gradient magnetic field coil even in a silent MRI apparatus. Is preferably arranged to ensure that its function is exhibited, while W
It is an object of the present invention to minimize the decrease in the efficiency of the B coil and thereby maintain the S / N and the efficiency of generating the magnetic field for spin excitation at good values during reception.

[0015]

According to the present invention, in order to achieve the above-mentioned object, the pressure is reduced to a pressure substantially lower than the atmospheric pressure by being surrounded by a wall having an outer peripheral side wall and an inner peripheral side wall. A controlled container is provided, a gradient magnetic field coil is arranged in the container, an RF coil is arranged outside the inner peripheral side wall of the container, and the inner peripheral side wall and the gradient magnetic field coil in the container are arranged. A shield structure for suppressing magnetic interference between the gradient magnetic field coil and the RF coil is provided between the coil and the coil structure of the MRI apparatus.

In this structure, preferably, the gradient magnetic field coil is a cylindrical coil assembly, and the shield is attached to an inner peripheral surface of the gradient magnetic field coil in the container. For example, a hole for venting air is formed in the shield body.

In each of the above-described configurations, for example, the RF coil is a whole-body RF coil. Further, a switch for electrically opening the whole-body RF coil in response to a control signal may be provided in the whole-body RF coil.

Further, in each of the above structures, for example,
The gradient coil is an active shielded gradient coil (ASGC) having a primary coil and a secondary coil for each of the X, Y and Z channels.

Further, a preferable example of each of the above-mentioned configurations is that the gradient magnetic field coil is supported by the container via an elastic body.

In each of the above-described configurations, a static magnetic field magnet is disposed on the outer peripheral side of the outer peripheral side wall of the container, and the static magnetic field magnet and the gradient magnetic field coil are connected to each other so that the load of the gradient magnetic field coil is reduced. You may support each separately, without hanging on a magnetic field magnet. For example, the static magnetic field magnet and the gradient magnetic field coil are separately supported directly on a floor or an installation site provided on the floor.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a coil structure of an MRI apparatus according to the present invention will be described below.

<First Embodiment> A first embodiment will be described with reference to FIGS.

FIG. 1 shows a magnet mount 1 of an MRI apparatus.
This magnet mount 1 is configured as a so-called silent type in which a gradient magnetic field coil is sealed in a vacuum vessel and arranged.

The magnet mount 1 is formed in a substantially cylindrical shape as a whole, and its bore forms a diagnostic space S. At the time of diagnosis, a subject P is inserted into the space by a bed top plate (not shown). ing. Here, the long axis direction of the magnet base is defined as the Z axis of the rectangular coordinate system.

A cylindrical superconducting magnet 11 is arranged on the floor on the outermost side in the radial direction (XY plane direction) of the magnet base 1. The magnet 11 is connected to a static magnetic field power supply (not shown), and generates a static magnetic field in the diagnostic space S.
It is assumed that the size of at least the radial direction of the superconducting magnet 11 is the same as that of an apparatus that does not include a silencing mechanism using a vacuum vessel described later.

A container 12 is arranged on the inner peripheral side of the superconducting magnet 11 so as to be supported by the magnet. The container 12 has an outer peripheral side wall 12A and an inner peripheral side wall 1 as a whole.
It is formed in a cylindrical shape having an internal space IS surrounded by 2B and a side body 12C, and is arranged so that its axial direction coincides with the Z-axis direction. The radial thickness of the internal space IS is set to an appropriate value that can be enclosed without contacting a later-described gradient coil assembly with a wall thereof (excluding a support portion). The container 12 is connected to a vacuum pump (not shown) and is adjusted to a pressure (vacuum) substantially lower than the atmospheric pressure at the time of diagnosis.

As shown in the drawing, an assembly of a gradient magnetic field coil 13 is arranged in the internal space IS of the container 12. The gradient magnetic field coil 13 forms an active shield type gradient magnetic field coil (ASGC) here. Specifically, as shown in FIG. 3, this coil assembly is formed by winding primary and secondary coils of X, Y, and Z channels in layers on a cylindrical resin spool 13A in an insulated state. (These layered winding coils are typically indicated by reference numeral 13B), and the whole is also formed into a substantially cylindrical assembly. The primary coil and the secondary coil of each channel are connected to a gradient magnetic field power supply (not shown) for each channel.
With this active shield type gradient magnetic field coil, the magnetic field when the coil is driven hardly leaks to the outside in the radial direction.

The assembly of the gradient magnetic field coil 13 is as follows.
As shown in FIGS. 1 and 2, in such an internal space IS,
The plurality of support portions 15,..., 15 with the elastic body 14 interposed therebetween are supported by the outer peripheral side wall body 12A. A power supply line (not shown) to the gradient magnetic field coil 13 is disposed so as to penetrate a part of the container 12 in an airtight manner.

Further, in the internal space IS of the container 12, a shield (shield body) 16
Affixed to the inner peripheral surface of the assembly. This shield is made of, for example, a copper foil of about 35 μm. In the present embodiment, the shield 16 is connected to a ground wire (not shown) that passes through the container 12 in an airtight manner, and is grounded outside the container. It should be noted that the shield 16 may be configured not to be grounded, and each of the wires connected to the shield 16 and the WB coil 17 may be hermetically pulled out of the container and connected to each other at a position as far away as possible. .

The shield 16 comprises a gradient coil 13
And a WB coil to be described later. The arrangement position of the shield 16 is one of the features of the present invention.

Outside the inner peripheral wall 12B of the container 12, that is, in the diagnostic space S, the RF
A WB coil (whole-body RF coil) 17 is disposed as a coil. The WB coil 17 is a transmitting / receiving RF coil.

The magnet mount 1 of the present embodiment is configured as described above. Therefore, the shield 16 allows the WB
Magnetic and electrical interference between the coil 17 and the gradient coil 13 is preferably eliminated or suppressed as in the prior art.

Further, since the assembly of the gradient magnetic field coil 13 is sealed in the container 12 in a substantially vacuum state, air is transmitted from the gradient magnetic field coil 13 to its external components, particularly, the magnet 11 during diagnosis. The amount is significantly reduced. For this reason, the generation of sound (noise) due to the magnet 11 being integrally vibrated with the gradient magnetic field coil 13 serving as a vibration source is greatly suppressed.

Further, the position where the shield 16 is mounted is WB
When viewed from the coil 17, the position is the farthest position in the physical permissible range, that is, the inner circumferential surface of the gradient coil 13 (the distance at this time is the radius r1 in FIG. 2). Therefore, the mounting position of the shield 16 is the best mounting position assumed from the prior art when viewed from the WB coil 17, that is, outside the inner peripheral side wall body 12B of the container 12 (the distance at this time is the radius r2 in FIG. 2). ), And further by the distance “r1−r2”. As a result, the efficiency of the WB coil is favorably maintained or improved.

The reason will be described in detail. The aforementioned document "Ma
genetic Resonance in Medici
ne 19, 180-185 (1991) ", placing the shield 16 outside the WB coil 17 requires Rm = Rsh ² / Rwb, as shown in FIG.
(Inner radius of WB coil = Rwb, inner radius of shield = R
This is equivalent to placing a virtual mirror image coil at a position determined by sh) in a direction opposite to the magnetic field generated by the WB coil. The magnetic field that reaches the subject P is the difference “the magnetic field created by the WB coil−the harmonic magnetic field created by the mirror image coil”. On the other hand, the magnetic field strength generated by each coil at the center point is about "1/1 /
Proportional to the inner radius of the coil.

Therefore, if the shield is arranged as far away from the WB coil as possible, the magnetic field generated by the virtual mirror image coil at the center position can be weakened. The wave magnetic field is strengthened. Therefore, the magnetic field substantially generated by the WB coil on the subject (= “the magnetic field generated by the WB coil−the harmonic magnetic field generated by the mirror image coil”) increases. Thereby, W
The transmission efficiency of the RF magnetic field and the reception efficiency of the MR signal of the B coil 17 can be maintained at values comparable to those of a conventional device having no silencing mechanism, or can be further improved.

The mounting position of the shield 16 according to the present invention is not limited to the position described in the first embodiment, that is, the inner peripheral surface of the assembly of the gradient coil 12 in the container 12. For example, shield 16
Any position (see the radius difference rd in FIG. 2) may be used as long as the space is between the inner surface of the inner peripheral wall body 12B of the container 12 and the inner peripheral surface of the assembly of the gradient magnetic field coil 12. As an example, even if the shield 16 is attached to the inner surface of the inner peripheral side wall body 12B, at least the efficiency of the WB coil 17 is improved by the thickness of the wall body 12B.

<Second Embodiment> A second embodiment will be described with reference to FIGS.

The coil structure of the MRI apparatus according to the present embodiment is different from the coil structure of the MRI apparatus when an RF coil other than the WB coil is used.
The present invention relates to a so-called "detune" mechanism for removing a B coil from a resonance system. In this embodiment, it is assumed that the shield is grounded through a ground wire that passes through the vacuum container in an airtight manner.

For comparison, FIG. 5 shows a conventional detuning mechanism. When a WB coil and a shield are electrically connected, a switch SW such as a PIN diode is inserted between the two, and the switch SW is connected to the shield. Some parts of the WB coil are connected to the shield through the shield. Since the shield is grounded, the WB coil is eventually grounded. As a result, the resonance frequency of the resonance circuit changes, resulting in a detuned state.

If this configuration is applied to the coil structure according to the present invention as it is, the shield is disposed in the container,
Wiring for electrically connecting the WB coil and the shield is complicated and increases. In particular, since these wires penetrate the container and are connected to the shield, many or large parts are required to maintain the airtightness, and the cost of parts is high. The structure becomes complicated, and the probability of lowering the degree of vacuum due to a failure or the like increases.

Therefore, in this embodiment, as shown in FIG. 6, a switch SW is inserted in series with the WB coil 17, and the switch SW is opened by a command from an external control circuit. The switch SW is, for example, a PIN diode. By opening the switch SW, the resonance frequency of the WB coil 17 is changed, and the above-described detune function is exhibited.

At this time, as can be seen from FIG.
It is not necessary to connect the coil 17 to the shield 16 (earth). For this reason, there is no need for a wiring structure in which the connection wire is passed through the container 12. Therefore, it is not necessary to make the container structure complicated as described above, the reliability of maintaining the airtightness is reduced, and the parts cost is increased.

<Third Embodiment> A third embodiment will be described with reference to FIGS.

The coil structure according to the present embodiment relates to an air vent structure when a shield is attached and installed.

The foil serving as the shield 16 is, for example, an adhesive, and is adhered inside the container 12, for example, to the inner peripheral surface of the assembly of the gradient coil 17. It is unavoidable that some air bubbles are generated between the shield material and the inner surface of the coil during this attachment. If the air pressure in the enclosure 12 is reduced for the purpose of silence, such bubbles may expand and the shield material may be deformed or peeled off.

In order to prevent this, a gel-like adhesive can be used instead of the adhesive, and the number of bubbles can be reduced.

In the present embodiment, the shield 16 is adhered with an adhesive, and as a countermeasure against generation of air bubbles, holes and / or slits are provided in the shield material for removing air in the air bubbles. FIG. 7 shows an example in which a hole 21 is formed in the shield 16, and FIG. 8 shows an example in which a slit 22 is provided in the shield 16. Of course, the hole 21 and the slit 22 may be provided in combination. The shape of the hole or slit is arbitrary. The size of the hole or slit is made small enough to be electrically negligible in a portion of the shield where the conductor is present, and is sufficiently large in a portion where the conductor is not provided with emphasis on air bubble removal.

As a result, when the pressure inside the container 12 is reduced,
Air bubbles generated between the shield 16 and the inner surface of the gradient magnetic field coil 17 also escape through the holes 21 and the slits 22. For this reason, peeling and deformation of the shield described above when only the adhesive is used can be prevented.

In order to achieve the object of this embodiment, the shield 16 itself may be formed of a fibrous or net-like conductive material.

<Fourth Embodiment> A fourth embodiment will be described with reference to FIGS.

The coil structure according to the present embodiment relates to the alignment between the shield and the WB coil during mounting or maintenance.

It is desirable that the shield and the WB coil have the same resonance frequency. In addition, to ensure sensitivity uniformity, it is desirable that the shield and the WB coil are coaxially arranged with an accuracy of 1 mm or less.

However, according to the coil structure according to the present invention, since the WB coil 17 is basically arranged outside the container 12 and the shield coil 16 is arranged inside the container 12, both the WB coil 17 and the shield coil 16 are arranged at the time of mounting and maintenance. Very difficult to align. Therefore, in this embodiment, an alignment adjusting means for facilitating such alignment is provided.

Specifically, as shown in FIG. 9, a small hole 17 is formed between the WB coil 17 and the inner peripheral side inner wall 12B of the container 12.
H and 12H are opened. Then, before lowering the air pressure in the container 12, as shown in FIG.
H, 12H to insert WB coil 17 and shield 16
The position of the WB coil 17 in the container radial direction is determined or adjusted while measuring the distance between the WB coil 17 and the WB coil 17. The gauge 23 has a scale. After the positioning (position adjustment) of the WB coil 17 is performed, as shown in FIG. 11, a plug 24 is plugged into the hole 12H of the inner peripheral side inner wall 12B, and the pressure in the container 12 is reduced to a desired value. At this time, since the stopper 24 is pulled toward the inside of the container 12, it does not fall off.

By this positioning (position adjustment), the shield 16 and the WB coil 17 can be coaxially arranged with an accuracy of 1 mm or less, and uniformity of sensitivity can be secured.

In each of the above embodiments, the gradient magnetic field coil 13 is provided in the container 12 and supported by the container.
Although the container 12 is structured to be supported by the static magnetic field magnet 11, a support structure described in, for example, Japanese Patent Application Laid-Open No. 10-118043 (Japanese Patent Application No. 8-274609) may be employed instead. That is, the gradient magnetic field coil 13 is
2 and on the floor (including a base portion such as a beam provided on the floor) by a supporting means separate from the static magnetic field magnet 11 (preferably a supporting means interposed by an elastic body or the like). Is to be supported. At this time, since the support means of the gradient magnetic field coil 13 extends through, for example, the side wall 12C of the container 12, a member for maintaining the airtightness between the support means and the container 12 is of course disposed. is there.

As a result, the vibration from the gradient magnetic field coil 13 to the static magnetic field magnet 11 due to air propagation can be reduced more reliably, and the means for supporting the gradient magnetic field coil 13 and the static magnetic field magnet 11 are different, and those means are different. As the position is farther on the floor, the vibration component transmitted from the gradient coil 13 through the structure (both the support means and the floor) and reaching the static magnetic field magnet 11 is further reduced. Therefore, the separate support structure can achieve more reliable noise reduction, and can also obtain the effect of the above-described coil structure.

Incidentally, the following example can be given as a further modified version of the above-mentioned basic configuration. One of them is a configuration in which the WB coil 17 is arranged in the container 12, whereby the shield can be set to zero potential to easily establish electrical connection with the WB coil. Another example is a configuration in which the inner peripheral side wall body 12 </ b> B of the container 12 is used as a winding frame of the WB coil 17. As described above, since the WB coil is desired to be located at the innermost side of the gantry, it is convenient to use the inner peripheral side wall body as the coil winding frame.

[0060]

As described above, according to the present invention, a container controlled at a pressure substantially lower than the atmospheric pressure is provided, a gradient magnetic field coil is disposed in the container, and an inner peripheral side wall of the container is provided. The RF coil is arranged outside the container, and the shield body that suppresses magnetic interference between the gradient magnetic field coil and the RF coil is arranged between the inner peripheral side wall body and the gradient magnetic field coil in the container. Even with the MRI apparatus, a shield for preventing electrical and magnetic interference between the WB coil and the gradient coil can be suitably arranged to reliably exert its function. A decrease in the efficiency of the WB coil due to the arrangement is minimized, whereby the S / N and the generation efficiency of the magnetic field for spin excitation during reception can be maintained at good values.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a magnet mount of an MRI apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of the container and the WB coil shown partially broken along line II-II in FIG. 1;

FIG. 3 is a partial cross-sectional view along the line III-III in FIG. 2;

FIG. 4 is a diagram illustrating a positional relationship among a WB coil, a shield, and a mirror image coil.

FIG. 5 is a diagram illustrating a conventional detune circuit.

FIG. 6 is a diagram illustrating a detune circuit according to a second embodiment of the present invention.

FIG. 7 is a view for explaining air vent holes provided in a shield according to a third embodiment of the present invention.

FIG. 8 is a diagram illustrating an air vent slit provided in a shield according to a third embodiment of the present invention.

FIG. 9 is a view for explaining positioning according to a fourth embodiment of the present invention.

FIG. 10 is another diagram illustrating the alignment according to the fourth embodiment of the present invention.

FIG. 11 is yet another diagram illustrating the alignment according to the fourth embodiment of the present invention.

FIG. 12 is a diagram illustrating a positional relationship among a WB coil, a shield, and a gradient magnetic field coil according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnet base 11 Static magnetic field magnet 12 Container 12A Outer side wall body 12B Inner side wall body 13 Gradient magnetic field coil 14 Elastic body 15 Support part 16 Shield (shield body) 17 WB coil (RF coil for whole body) 21 Air vent hole 22 Air vent Slit SW switch

Claims (9)

[Claims] 1. A container surrounded by a wall having an outer peripheral side wall and an inner peripheral side wall and controlled at a pressure substantially lower than the atmospheric pressure, wherein a gradient magnetic field coil is arranged in the container. An RF coil is arranged outside the container on the inner peripheral wall of the container to suppress magnetic interference between the gradient coil and the RF coil between the inner peripheral wall and the gradient coil in the container. A coil structure of an MRI apparatus, wherein a shield body is disposed. 2. The coil structure of an MRI apparatus according to claim 1, wherein the gradient magnetic field coil is a cylindrical coil assembly, and the shield is attached to an inner peripheral surface of the gradient magnetic field coil in the container. A coil structure of an MRI apparatus, characterized in that: 3. The coil structure of an MRI apparatus according to claim 2, wherein a hole for venting air is formed in said shield body. 4. The M according to claim 1, wherein
The coil structure of an MRI apparatus, wherein the RF coil is a whole-body RF coil. 5. The MRI apparatus according to claim 4, wherein a switch for electrically opening the whole-body RF coil in response to a control signal is provided on the whole-body RF coil. The coil structure of the device. 6. The coil structure of an MRI apparatus according to claim 1, wherein said gradient magnetic field coil has a primary coil and a secondary coil for each of X, Y, and Z channels. M that is a shielded gradient magnetic field coil (ASGC)
Coil structure of RI device. 7. The MRI apparatus according to claim 1, wherein the gradient magnetic field coil is supported by the container via an elastic body. Coil structure. 8. The coil structure of an MRI apparatus according to claim 1, wherein a static magnetic field magnet is arranged on the outer peripheral side of the outer peripheral side wall of the container, and the static magnetic field magnet and the inclined magnetic field magnet are arranged. A coil structure of an MRI apparatus, wherein a magnetic field coil and a magnetic field coil are separately supported without applying a load of the gradient magnetic field coil to the static magnetic field magnet. 9. The MRI apparatus according to claim 8, wherein said static magnetic field magnet and said gradient magnetic field coil are directly supported on a floor or an installation site provided on the floor, respectively. Coil structure.