JP5507531B2 - Magnetic resonance imaging system - Google Patents

Description

  The present invention relates to a magnetic resonance imaging apparatus in which at least an inner shape of a cross section of a gradient magnetic field coil is horizontally long.

  A magnetic resonance imaging apparatus mainly includes a static magnetic field magnet such as a superconducting magnet that generates a static magnetic field in an imaging space, and an RF (radio frequency) for generating a nuclear magnetic resonance (NMR) signal from a subject. ) Coil and a gradient magnetic field coil for generating a gradient magnetic field to give position information to the NMR signal.

In general, with a subject (patient) as the center, a static magnetic field magnet is disposed on the outermost side, a gradient magnetic field coil is disposed on the inner side, and an RF coil is disposed on a position closest to the subject on the inner side.
A patient who is a subject is photographed by entering a cylindrical structure formed by a gradient magnetic field coil and an RF coil while lying on his / her back on an examination bed. Details of the structure and principle of MRI are described in, for example, Patent Document 1 and Patent Document 2.

  Conventionally, the cross-sectional shape of the gradient magnetic field coil and the RF coil has been circular. However, in order to reduce the patient's feeling of pressure, it has been proposed to expand the space for the patient to enter and to make the cross-sectional shape an oblong shape like an ellipse. ing. For example, Patent Document 3 shows a structure in which the outer cross-sectional shape of the gradient magnetic field coil is circular, but the inner cross-sectional shape is horizontally long.

JP 2009-142646 A JP 2008-119214 A JP 2011-72461 A

By the way, as described above, when the width of the horizontally long cross section inside the gradient magnetic field coil is increased in order to ensure a sufficient space for a patient to enter, the thickness of the left and right side portions is thinner than before in terms of molding. Become. By reducing the thickness of the side surface portion, the rigidity is reduced due to the reduction of the section modulus, and the vibration generated in the gradient magnetic field coil when the magnetic field is generated becomes larger than before.
The vibration of the gradient magnetic field coil is also transmitted to the inner RF coil, and the vibration of the RF coil may be larger than before.

  Furthermore, in order to increase the width in the longitudinal direction of the cross section of the RF coil as much as possible, a structure in which the most outwardly projecting portion of the side surface portion of the substantially elliptical RF coil having a major axis in the horizontal direction is brought into contact with the gradient magnetic field coil. The case is considered. In this case, the vibration of the RF coil having the contact structure may further increase with the oscillating gradient magnetic field coil.

  However, a plurality of electronic components such as coils and capacitors are mounted on the outer surface (outer surface) of the RF coil. When the vibration of the RF coil increases more than before, there is a concern that the connection part of the electronic component is disconnected due to external force. In particular, an electronic component mounted on a circuit board made of glass epoxy or the like fixed on the outer surface of the RF coil is concerned that the circuit board itself resonates at a natural frequency and vibrates more and is disconnected. The

  In view of the above circumstances, the present invention provides a magnetic resonance imaging apparatus in which the connection reliability of electronic components mounted on the substrate is high and the object space is wide by suppressing the vibration of the substrate fixed to the surface of the RF coil. With the goal.

  In order to achieve the above object, a magnetic resonance imaging apparatus according to the first aspect of the present invention is a magnetic resonance imaging apparatus using a magnetic resonance phenomenon, and is provided inside a cylindrical gradient magnetic field coil and the gradient magnetic field coil. An RF coil having a cylindrical shape and a flat cross section perpendicular to the central axis direction, a substrate fixed on the surface of the RF coil between the two coils, and a plurality of electronic components connected thereto, A reinforcing plate attached to a surface of the substrate opposite to the electronic component mounting surface via a first adhesive material is provided.

A magnetic resonance imaging apparatus according to a second aspect of the present invention is a magnetic resonance imaging apparatus using a magnetic resonance phenomenon, and is provided with a cylindrical gradient magnetic field coil and an inner side of the gradient magnetic field coil, and has a cylindrical shape. a RF coil that the cross-sectional shape perpendicular to the central axis direction is a flat shape, said fixed on the RF coil surface between both coils, a substrate on which a plurality of electronic components are connected, said in the substrate electronic A supporting member is provided on a surface opposite to the component mounting surface at a position where the RF coil is fixed to the RF coil via a second adhesive material.

  According to the present invention, it is possible to realize a magnetic resonance imaging apparatus with high connection reliability of an electronic component mounted on a substrate and a wide object space by suppressing vibration of the substrate fixed on the surface of the RF coil.

It is a figure which shows schematic structure of the gradient magnetic field coil and RF coil periphery seen from the front side of the magnetic resonance imaging apparatus of Embodiment 1 concerning this invention. It is the sectional view on the AA line of FIG. It is a perspective view which shows schematic structure of RF coil. It is a top view which shows the conventional glass epoxy test board which connected the electronic component to the center part. It is a figure which shows the relationship between the input acceleration amplitude by the vibrator not shown at the time of setting the span fixed with a volt | bolt to 90 mm, and the response acceleration amplitude of a test board | substrate. It is a figure which shows the relationship between an input acceleration amplitude and the frequency | count of the sweep in which the disconnection of the electronic component generate | occur | produced using a fixed span as a parameter. It is a figure which shows the model for calculating | requiring analytically the stress which generate | occur | produces on the circuit board surface by vibration. (a) is the top view which looked at the circuit board of Embodiment 1 from the to-be-fixed surface side, (b) is a B direction arrow directional view of (a), (c) is a C direction arrow of (a). FIG. It is a perspective view which shows a support plate. It is a perspective view which shows an annular | circular shaped support plate material. (a) is the top view which looked at the circuit board of Embodiment 2 from the to-be-fixed surface side, (b) is a D direction arrow view of (a), (c) is an E direction arrow of (a). FIG. (a) is the top view which looked at the circuit board of Embodiment 3 from the to-be-fixed surface side, (b) is a F direction arrow view of (a), (c) is a G direction arrow of (a). FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<< Embodiment 1 >>
FIG. 8 shows a schematic structure of a substrate fixed to the RF coil according to the first embodiment.
FIG. 1 shows a schematic structure of a gradient coil and an RF coil peripheral portion viewed from the front side of the magnetic resonance imaging apparatus according to the first embodiment of the present invention. FIG. 2 shows a schematic structure of the cross section taken along line AA of FIG.

The magnetic resonance imaging apparatus (MRI) M of Embodiment 1 puts a subject (patient) P in a magnetic field, generates a nuclear magnetic resonance phenomenon in an atomic body, for example, a hydrogen (H) nucleus, and the nuclear magnetic field. It is a device for detecting abnormalities in the body by detecting and imaging electromagnetic waves obtained by the resonance phenomenon.
The atomic nucleus may be other atomic nucleus such as carbon (C) other than hydrogen, phosphorus (P), sodium (Na), or the like.

  The magnetic resonance imaging apparatus M receives a static magnetic field magnet 5 such as a superconducting magnet that generates a static magnetic field in an imaging space S where a subject (patient) P lies, and a nuclear magnetic resonance (NMR) signal (electromagnetic wave) from the subject P. An RF coil 2 for generating and receiving and a gradient magnetic field coil 1 for generating a gradient magnetic field to give positional information to the NMR signal are configured.

  In the magnetic resonance imaging apparatus M, a static magnetic field magnet 5 in which a substantially cylindrical space is formed is arranged on the outermost side around a subject (patient) P, and a cylindrical gradient magnetic field coil 1 is installed on the inner side. Further, the cylindrical RF coil 2 is installed at a position closest to the subject (patient) P inside.

The gradient magnetic field coil 1 is formed by winding a coil in the imaging space S in order to generate a gradient magnetic field by a current flowing through the gradient magnetic field coil 1.
The gradient magnetic field coil 1 has a substantially cylindrical shape on the outer surface, and has a substantially elliptic cylindrical shape on the inner surface to accommodate the RF coil 2 in order to secure a sufficient space for the subject (patient) P. In other words, the gradient coil 1 has a cylindrical shape, and the inner surface of the cross section perpendicular to the central axis has a horizontally long flat shape.

FIG. 3 shows a schematic structure of the RF coil.
The RF coil 2 forms a high-frequency magnetic field in order to generate an NMR signal from the subject P, and detects the NMR signal from the subject P.
The RF coil 2 has a cylindrical shape, and in order to ensure a sufficient space for the subject P, the RF coil 2 has a flat shape whose cross section perpendicular to the central axis is horizontally long.

The RF coil 2 has a bobbin 6 having flange portions 6a and 6b formed at both end edges in the central axis direction and a cylindrical body portion 6c between the flange portions 6a and 6b on the innermost side. The bobbin 6 is made of a resin such as glass epoxy.
The RF coil 2 is formed by winding a thin film sheet 6 s such as glass epoxy with a copper foil 7 around the outer peripheral surface of the body portion 6 c of the bobbin 6. The copper foil 7 of the RF coil 2 is connected to electronic components such as a capacitor 8 and a coil 9 at various places.

  Further, on the outer surface (surface) of the RF coil 2, a circuit board 12 on which a plurality of electronic components such as a capacitor 28 and a coil 29 are mounted (mounted) is screwed with bolts, nuts, and the like. The circuit board 12 is made of, for example, glass epoxy, and a wiring pattern is formed by etching or the like.

The circuit board 12 is a board for power supply wiring to the RF coil 2, and the circuit board 12 and its wiring 13 are bobbins in order to suppress electromagnetic influence on the coil (copper foil 7, coil 9, etc.). 6 away from the copper foil 7 on the top.
As shown in FIGS. 1 and 2, the gradient magnetic field coil 1 and the RF coil 2 are fixed to the housing of the static magnetic field magnet 5 via the respective supports 3 and 4.

  As described above, when the inside of the gradient magnetic field coil 1 has a horizontally long flat structure that is long in the horizontal direction, that is, a substantially elliptical shape having a long diameter in the horizontal direction, the thickness of both side surface portions 1s (see FIG. 1). ) Becomes thinner than before. As described above, since the shape of the gradient magnetic field coil 1 is not symmetric with respect to the central axis, the stress generated in the gradient magnetic field coil 1 when the magnetic field is applied to the imaging space S becomes non-uniform, and the vibration thereof becomes larger than the conventional one. Is assumed. Therefore, the vibration transmitted from the gradient magnetic field coil 1 to the RF coil 2 may increase.

  Further, in order to increase the width in the longitudinal direction of the RF coil 2 in the longitudinal direction (the dimension of the major axis extending in the horizontal direction of a substantially elliptical cross section) as much as possible, the side portion 2s of the most protruding portion on the side of the RF coil 2 is used. Is brought into contact with the gradient coil 1, the vibration of the gradient coil 1 is always transmitted directly to the RF coil 2, and there is a concern that the vibration of the RF coil 2 further increases.

Actually, an experiment was conducted to measure the vibration generated in the RF coil 2 by sweeping (changing) the electromagnetic frequency applied to the flat RF coil 2 having a horizontally long cross section. An example in which vibration acceleration about ten times that of a coil is measured has been reported.
When the connection reliability of the electronic components such as the capacitor 8 and the coil 9 directly connected to the outer surface (surface) of the RF coil 2 is examined by analysis or the like, even when about ten times the vibration as described above is applied, the connection It was revealed that only a small strain was generated in the part, and the fear of disconnection was small.

In contrast, electronic components (capacitor 28, coil 29, etc.) mounted (mounted) on the circuit board 12 fixed to the outer surface of the RF coil 2 may be disconnected from the following results. It is judged that there is. The experimental results showing the basis will be described below.
In the experiment, a conventional glass epoxy circuit board 14 in which an electronic component 16 is connected to the central portion shown in FIG. 4, that is, a circuit board 14 having an outer dimension of 100 × 50 mm and a standard thickness of 1.6 mm. Then, the connection life of the electronic component 16 was examined when four places were fixed with bolts 15 and the vibration with the frequency swept (changed) by the vibrator was applied thereto.

FIG. 5 shows the relationship between the input acceleration amplitude by a vibrator (not shown) and the response acceleration amplitude of the circuit board when the fixed span s fixed by the bolt 15 is 90 mm.
In the tested range, it has been found that the circuit board 14 has resonance points, that is, natural frequencies around 600 Hz (580 Hz of peak (1) in FIG. 5) and 3000 Hz (3140 Hz of peak (2) in FIG. 5). . In particular, at the resonance point near 600 Hz (peak (1) in FIG. 5), when the input acceleration amplitude was 100 m / s ² , the circuit board 14 generated a large vibration with a total amplitude of about 2 mm.

FIG. 6 shows the relationship between the input acceleration amplitude and the number of sweeps in which the disconnection of the electronic component has occurred, with the fixed span s as a parameter. The vertical axis of FIG. 6 represents the input acceleration amplitude (m / s ² ) applied to the test substrate 14, and the horizontal axis of FIG. 6 represents the number of sweeps (times) at which the electronic component is disconnected.
In the case of an input acceleration amplitude of 100 m / s ² and a fixed span of 90 mm marked with ●, a disconnection occurred after about 10 sweeps. In the vibration measurement of the RF coil 2 having a horizontally long cross-sectional shape, the vibration acceleration amplitude in the vicinity of the excitation frequency of 600 Hz was about 100 m / s ² .

Therefore, when the circuit board 12 (see FIG. 3) on the RF coil 2 is fixed with the same fixed span 90 mm as the test circuit board 14 as in the conventional case, it was predicted that the disconnection occurred in a very short period of time. That is, the circuit board 12 on the RF coil 2 is expected to break in about 10 sweeps from the input acceleration amplitude of 100 m / s ² with a fixed span of 90 mm indicated by ● in FIG.

Here, in order to reduce the vibration of the circuit board 12 (see FIG. 3) on the RF coil 2 and prevent the disconnection of the electronic components mounted on the circuit board 12, the section coefficient of the circuit board 12 is increased. Then, since the stress σ decreases, it is effective to make the thickness of the circuit board 12 thicker than before.
When considering a beam loaded with distributed load w (load w per unit length) due to acceleration (a) as shown in FIG. 7, the position of the surface from the neutral axis in the center is determined by the material mechanics formula. The stress σ at h / 2 is expressed by the following equation (1).

ここで、Ｌは固定スパン(固定箇所の距離)(図４の固定スパンｓ)、ｂ、ｈはそれぞれ回路基板の幅、厚さ、ａは振動加速度、rは回路基板の密度である。

Here, L is a fixed span (fixed portion distance) (fixed span s in FIG. 4), b and h are the width and thickness of the circuit board, a is the vibration acceleration, and r is the density of the circuit board.

Since the distributed load w is expressed as force = mass × acceleration, it is expressed as w = a × rbh using the mass rbh per unit length of the beam.
From equation (1), it can be seen that the stress of the circuit board 12 is inversely proportional to its thickness h.
Therefore, for example, if the thickness h is about 3 mm, which is twice the conventional 1.6 mm, the stress σ is reduced to ½ and the acceleration a is reduced to ½ from the equation (1). .

However, circuit boards made of glass epoxy with a standard thickness of 1.6 mm or more are generally not commercially available and are custom-made products, so using a circuit board outside the standard dimensions slightly increases the cost. Invite you.
Therefore, as shown in FIG. 8, the apparent sectional modulus is increased by attaching (in contact with) a reinforcing plate 19 such as vinyl chloride to the circuit board 12 on which the capacitor 28 and the coil 29 are mounted (mounted). It is effective to reinforce the rigidity of the circuit board 12 against vibration.

When the circuit board 12 is attached to the reinforcing plate 19, if an adhesive tape having a viscoelastic property or an adhesive material 21a of an adhesive material is used, the damping effect due to the viscous damping force by the adhesive material 21a such as the adhesive tape, The effect of suppressing the vibration peak at the resonance point (natural frequency) can also be expected.
Further, in order to prevent the adhered reinforcing plate 19 from being peeled off due to vibration, in addition to the fixing portions k1, k2, k3, k4 at the four locations to the RF coil 2 of the circuit board 12, the center of the circuit board 12 is provided. It is desirable to provide the fixing parts k5 and k6 also near the part.

By providing the fixing portions k5 and k6 at the center of the circuit board 12, each fixing span between the fixing portion k5 and the fixing portion k1 or the fixing portion k4 and each fixing span between the fixing portion k6 and the fixing portion k2 or the fixing portion k3. However, when the fixed portions k5 and k6 are not provided in the vicinity of the central portion, the vibration (amplitude) reduction effect due to being smaller than the fixed span between the fixed portions k1 and k4 and the fixed span between the fixed portions k2 and k3. Can also be expected.
This is because each fixed span is the distance between the vibration nodes, so the distance between the vibration nodes is shorter when the fixed parts k5 and k6 are provided near the center than when the fixed parts are not provided. is there.

The effect of reducing the fixed span L, that is, the distance between the vibration nodes of the fixed portion distance is apparent from the equation (1) and the experimental results shown in FIG.
For example, if L is 1/2 (45 mm), the stress σ is proportional to L ² from Equation (1), so the stress σ is reduced to ¼, and the acceleration a at which the stress σ is proportional is ¼. An effect equivalent to that reduced to the above can be obtained. Furthermore, if implemented together with a measure for doubling the circuit board thickness h where the stress σ is inversely proportional to the equation (1), the same effect as when the acceleration is reduced to 1/8 of 1/2 × 1/4 is obtained. It is possible to approach the conventional vibration level that has been obtained and has no problem.

On the other hand, from the experimental results of FIG. 6, for example, when the span is set to 30 mm, it can be confirmed that this corresponds to a life at an acceleration of about 5 times the life at the acceleration amplitude of 100 m / s ² in the case of the conventional span of 90 mm. That is, from FIG. 6, the number of sweeps where the acceleration amplitude is 100 m / s ² when the span is 90 mm (marked with ● in FIG. 6) is about 500 m / s when the span is 30 mm (marked with ■ in FIG. 6). It can be seen that this roughly corresponds to the number of sweeps where s ² is broken.

From this, it can be said that when the span of the fixed portions (k1 to k6) of the circuit board 12 is 30 mm, the same effect as that obtained when the vibration acceleration is reduced by about 1/5 can be obtained.
By implementing this together with a measure for doubling the thickness h of the circuit board 12 (same as the effect of σ is ½ and acceleration a is ½ from the equation (1)), the acceleration can be reduced. This is equivalent to a reduction to 1/10, and the effect of reducing the acceleration to the same level as before can be obtained.

Further, when considering the value of L ² / h in equation (1), there is a concern about disconnection of electronic components at an input acceleration amplitude of 100 m / s ^{2. The} span L is 90 mm and the thickness h is the circuit board. In the case of a combination with a standard thickness of 1.6 mm, L ² / h is 5060 mm.

As described above, in the flat RF coil 2 having a horizontally long cross section, vibration acceleration of about ten times that in the case of a conventional cylindrical RF coil has been reported. Is reduced to a level equivalent to that of the prior art, the acceleration a applied to the circuit board 12 is ten times higher. Therefore, when the density r of the circuit board 12 is equal, the value of L ² / h is set to at least 1/10. It is necessary to reduce to about 500 mm or less.

If the fixed span L is experimentally confirmed to be 1/5, the fixed span L is 30 mm, and the thickness h is 3 mm, twice the standard thickness of 1.6 mm, the total stress reduction effect will be less than 1/10. In this case, L ² / h is 300 mm. Therefore, if L ² / h can be set to 300 or less, it is desirable to ensure the reliability of connection of electronic components more reliably.

FIG. 8 is a diagram showing an example of a schematic structure of a circuit board fixed on an RF coil and mounted with an electronic component. 8A is a plan view of the circuit board as viewed from the fixed surface side, FIG. 8B is a view taken in the direction of arrow B in FIG. 8A, and FIG. 8C is the RF coil 2. It is the C direction arrow directional view of Fig.8 (a) seen in the tangent direction of the outer periphery.
As shown in FIG. 8A, it is necessary to stably fix the circuit board 12 on a curved surface protruding outward of the body portion 6c of the bobbin 6 of the RF coil 2.

As shown in FIG. 8 (b), the RF coil 2 is formed in a convex shape on the lower surface of the flat circuit board 12. When the circuit board 12 is fixed to the convex outer surface of the RF coil 2 as it is, the center portion is formed. The contact with the RF coil 2 is brought into a non-contact state in which the edge is lifted from the RF coil 2.
Therefore, two strip-shaped support plates 20 (20A, 20B) shown in FIG. 9 are further attached to the lower portion of the reinforcing plate 19 facing the circumferential edge of the RF coil 2 of the circuit board 12, and the adhesive material 21 is attached. Paste through. The pressure-sensitive adhesive material 21 is a pressure-sensitive adhesive tape or adhesive material having viscoelastic characteristics, and has an effect of suppressing a vibration peak at a resonance point (natural frequency) due to a damping effect due to viscous damping by the pressure-sensitive adhesive material 21.

And as shown in FIG.8 (c), the male screw part of the volt | bolt 10 is penetrated to the hole drilled in each of the circuit board 12, the adhesive material 21a, the reinforcement board 19, the adhesive material 21, and the support plate 20, The circuit board 12 is attached to the RF coil 2 by screwing the bolt n to the male screw portion of the bolt 10.
The support plate 20A shown in FIG. 9 has an elongated strip shape with a thin plate thickness, and the male screw portion of the bolt 10 (see FIG. 8) is inserted into each position of the fixing portions k1, k5, and k4. Insertion holes a1, a5, and a4 are penetrated.

Similarly, the support plate 20B has an elongated strip shape with a thin plate thickness, and the male screw portion of the bolt 10 (see FIG. 8) is inserted into each position of the fixing portions k2, k6, and k3. Holes a2, a6, and a3 are provided.
Support plate 20 (20A, 20B), for example, a resin such as vinyl chloride, rubber or the like is used, and is not particularly limited. However, the support plate 20 is preferably made of a material that has a function of damping the vibration transmitted to the circuit board 12.

The strip-shaped support plate 20 is expected to have an effect as a reinforcing plate for the circuit board 12 and further effectively acts to reduce vibration.
The circuit board 12 is fixed (k1 to k6) with bolts 10 and nuts n at the longitudinal positions of the support plate 20 (20A, 20B) along the central axis of the RF coil 2, and both ends of the support plate 20A. It is preferable to fix at (k1, k4) and the central portion (k5), and at each of three or more locations on both ends (k2, k3) and the central portion (k6) of the support plate 20B.

Since the support plate 20 (20A, 20B) in the direction along the central axis of the RF coil 2 is fixed at the longitudinal position, the distance between the lower surface of the circuit board 12 and the outer surface (front surface) of the RF coil 2 is equal. This is because peeling (peeling) of the support plate 20 (20A, 20B) from the outer surface of the circuit board 12 or the RF coil 2 can be suppressed.
The support plate 20 (20A, 20B) may be an annular support plate material 30 shown in FIG. 10 provided independently in each of the fixing portions k1 to k6.

Each support plate 30 is provided with an insertion hole 30a through which the male screw portion of the bolt 10 is inserted. The support plate 30 is made of, for example, a resin such as vinyl chloride, rubber, or the like, and is not particularly limited. However, a material having a damping action for the vibration of the circuit board 12 is more preferable for the support plate 30.
Although FIG. 10 illustrates the case where the support plate 30 is annular, the shape is not limited as long as a clearance can be formed between the circuit board 12 and the RF coil 2.

Moreover, although the supporting plate 20 (20A, 20B) of FIG. 9 fixed the fixing part three by three and illustrated the supporting member that fixes the supporting plate material 30 fixing part of FIG. 10 one by one, the circuit board 12 and the RF coil The number of fixing portions to be fixed can be arbitrarily selected as long as a clearance can be formed between the two and the vibration damping function.
In FIG. 8, only main components (capacitor 28 and coil 29) on the circuit board 12 are shown, and other components, wiring, wiring patterns, and the like are omitted.

In the example shown in FIG. 3, the number of circuit boards 12 is exemplified, but a plurality of circuit boards 12 are similarly fixed. Furthermore, although the position of the circuit board 12 is shown as the upper part of the RF coil 2 in FIG. 3, it may be connected to other positions, that is, a side surface part or a lower part. In any case, the same measures for preventing disconnection can be obtained by the measures described above.
The mounting position of the circuit board 12 is desirable from the viewpoint of space because the RF coil 2 has a flat shape, and there are empty spaces above and below it, making it easy to connect input / output terminals. On the other hand, both side portions of the RF coil 2 (side portions 2s in FIG. 1) tend to become vibration nodes when vibrations occur, and the vibration amplitude tends to be small, which is desirable from the viewpoint of vibration isolation of the circuit board 12.

According to the above configuration, it is possible to suppress the vibration of the circuit board 12 fixed to the surface (outer surface) of the RF coil 2 and improve the reliability of the connection part of the electronic component on the circuit board 12.
Accordingly, it is possible to provide a magnetic resonance imaging apparatus M having a laterally long gradient magnetic field coil 1 cross-sectional inner shape and an RF coil 2 cross-sectional shape having a wider space for the subject (patient) P.

<< Embodiment 2 >>
Next, the magnetic resonance imaging apparatus M of Embodiment 2 will be described.
FIG. 11 shows a schematic structure of a circuit board fixed to the RF coil according to the second embodiment. 11A is a plan view of the circuit board as viewed from the fixed surface side, FIG. 11B is a view in the direction of arrow D in FIG. 11A, and FIG. 11C is the RF coil 2. It is the E direction arrow directional view of Fig.11 (a) seen in the tangent direction of the outer periphery.

In the second embodiment, unlike the circuit board 12 of the first embodiment, a part of the fixing portion (k25, k26) of the circuit board 22 is replaced with the reinforcing plate 19 and only the support plate 20 (including the adhesive material 21). It is set as the structure fixed to.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

In the example shown in FIG. 11 of the second embodiment, the fixing portions k25 and k26 at two central portions of the circuit board 22 are affixed (provided in contact with) the reinforcing plate 19 and the support plate 20 below the circuit board 22. Only the structure (including the adhesive 21) is fixed to the RF coil 2.
In the fixing portions k25 and k26 of the reinforcing plate 19, the bolt head 10t of the fixing bolt 10 is accommodated on the installation surface side of the circuit board 22 so that the bolt head 10t of the fixing bolt 10 does not protrude from the circuit board 22. A counterbore (concave) portion 17 is provided.

This structure is disadvantageous from the viewpoint of preventing the reinforcing plate 19 from being peeled off from the circuit board 22, but without being restricted by the presence of the fixing bolt 10 or without being obstructed, the capacitor 28, the coil The advantage that electronic components such as 29 can be mounted on the circuit board 22 is obtained.
Further, it is easy to increase the number of places where the circuit board 22 is fixed to the RF coil 2 and to suppress vibration more firmly, which is also advantageous.

  In the second embodiment, the circuit board 22 and the reinforcing plate 19 are provided with the concave counterbore (concave) portion 17 so that the fixing bolt head 10t does not protrude from the outer surface of the fixing portion near the center of the circuit board 22. In the fixing portions k21 to k24 of the corner portion of the circuit board 22, the concave counterbore (concave) portion 17 is provided on the circuit board 22 and the reinforcing plate 19, and the bolt head 10t of the fixing bolt 10 is attached to the circuit board 22. You may comprise so that it may not protrude to an outer surface. Further, at least one of the fixed portion of the corner portion of the circuit board 22 or the fixed portion near the center may be configured such that the bolt head 10t of the fixing bolt 10 does not protrude from the circuit board 22.

<< Embodiment 3 >>
Next, the magnetic resonance imaging apparatus M of Embodiment 3 will be described.
In the third embodiment, the circuit board 32 (32A, 32B) corresponding to the circuit board 12 of the first embodiment is divided.
FIG. 12 shows a schematic structure of a circuit board fixed to the RF coil according to the third embodiment. 12A is a plan view of the circuit board as viewed from the fixed surface side, FIG. 12B is a view taken in the direction of arrow F in FIG. 12A, and FIG. It is the G direction arrow line view of Fig.12 (a) seen in the tangent direction of the outer periphery.

  When the fixing parts k5 and k6 (see FIG. 8) and the fixing parts k25 and k26 (see FIG. 11) are provided at the center of the circuit boards 12 and 22 as in the first and second embodiments, the bobbin of the RF coil 2 6 may cause the circuit boards 12 and 22 to be deformed, which may affect the connection reliability of electronic components such as the capacitor 28 and the coil 29.

Therefore, in the example shown in FIG. 12 of the third embodiment, the circuit board 32, the reinforcing plate 19, and the support plates 20A and 20B are each composed of two circuit boards 32A and 32B, two reinforcing plates 19A and 19B, and two sets. The support plates 20A1, 20B1, 20A2, and 20B2 are divided into fixed structures ka311 to ka34 at corners of the circuit board 32A and fixed parts kb31 to kb34 at corners of the circuit board 32B.
Thereby, the influence of the deformation | transformation of the bobbin 6 is open | released in the space p1 into which the circuit board 32A, the reinforcement board 19A, support board 20A1, 20B1, and the circuit board 32B, the reinforcement board 19B, and support board 20A2, 20B2 were divided | segmented. I am doing so. The two circuit boards 32A and 32B are connected by wiring 52 to achieve electrical connection.
In the third embodiment, the case where the circuit board 32, the reinforcing plate 19, and the support plates 20A and 20B are each divided into two parts is illustrated, but may be divided into two or more parts.

<< Other Embodiments >>
In the above-described embodiment, the case where the reinforcing plate 19 is attached to the circuit boards 12, 22, and 32 has been exemplified. However, by increasing the strength of the circuit boards 12, 22, and 32, or by forming them thickly, the reinforcing plate 19 ( You may comprise without providing 19A, 19B).

  Moreover, in the said embodiment, although the case where the circuit boards 12, 22, and 32 were fixed to the RF coil 2 in the corner part 4 places was illustrated, if it is three or more places which can fix a flat circuit board stably, it will be a fixed place The number of is not limited. Moreover, it is good also as a structure which fixes edge parts other than the corner part of a circuit board. However, fixing the circuit board at the four corners facilitates the fixing operation and can be stably fixed to the RF coil 2, which is most desirable.

  In the above embodiment, the circuit board 12 is fixed to the RF coil 2 by using bolts, nuts or the like. However, the circuit board 12 may be fixed by elastic deformation using an elastic material such as resin. In addition, as a method for fixing the circuit board 12 to the RF coil 2, a method other than bolts can be appropriately selected.

In the above-described embodiment, various configurations have been described, but the configurations described may be appropriately combined. Thereby, there exists a combined effect.
While various embodiments of the present invention have been described above, the description is intended to be exemplary. And many more embodiments are possible within the scope of the present invention. That is, various changes and modifications are possible within the scope of the present invention.

1 Gradient magnetic field coil 2 RF coil 8, 28 Capacitor (electronic component)
9, 29 Coils (electronic parts)
12, 22, 32, 32A, 32B Circuit board (board)
17 Counterbore (recess)
19 Reinforcement plate 20 Support plate (support member)
21 Adhesive (second adhesive)
21a Adhesive material (first adhesive material)
30 Support plate material (support member)
32, 32A, 32B Circuit board (divided board)
52 Wiring h Thickness (Thickness of substrate and reinforcing plate combined)
k1 to k6, k21 to k26, ka31 to ka36, kb31 to kb36 fixing part ka31 to ka36, kb31 to kb36 fixing part L fixing span ((minimum) interval of the fixing part of the substrate to the RF coil)
M magnetic resonance imaging system

Claims (13)

A magnetic resonance imaging apparatus using a magnetic resonance phenomenon,
A cylindrical gradient magnetic field coil;
An RF coil that is provided inside the gradient magnetic field coil and has a cylindrical shape and a cross section perpendicular to the central axis direction thereof is a flat shape;
A substrate fixed on the surface of the RF coil between the two coils and to which a plurality of electronic components are connected;
A magnetic resonance imaging apparatus, comprising: a reinforcing plate attached to a surface of the substrate opposite to the electronic component mounting surface via a first adhesive material. The magnetic resonance imaging apparatus according to claim 1.
A magnetic resonance imaging apparatus comprising: a support member that is attached to the RF coil on a surface of the substrate opposite to the attachment surface of the reinforcing plate at a position where the RF coil is fixed via a second adhesive material. . The magnetic resonance imaging apparatus according to claim 1 or 2,
The magnetic resonance imaging apparatus according to claim 1, wherein a fixing portion of the substrate to the surface of the RF coil is provided near an edge of the substrate and a central portion of the substrate. A magnetic resonance imaging apparatus using a magnetic resonance phenomenon,
A cylindrical gradient magnetic field coil;
An RF coil that is provided inside the gradient magnetic field coil and has a cylindrical shape and a cross-sectional shape perpendicular to the central axis direction is a flat shape;
The fixed onto the RF coil surface between both coils, a substrate on which a plurality of electronic components are connected,
A magnetic resonance imaging apparatus, comprising: a support member attached via a second adhesive material at a position where the RF coil is fixed to a surface of the substrate opposite to the electronic component mounting surface. The magnetic resonance imaging apparatus according to claim 4.
The magnetic resonance imaging apparatus, wherein the fixing portion of the substrate is provided near an edge portion of the substrate and a central portion of the substrate. The magnetic resonance imaging apparatus according to claim 1 or 2,
The fixed portion of the substrate is provided at an edge portion of the substrate, and the reinforcing plate is fixed to the RF coil near the central portion of the substrate,
The magnetic resonance imaging apparatus according to any one of claims 1 to 4, wherein a recess for accommodating a head of a fixing member for the substrate is provided at any of the fixing portion positions on the surface of the reinforcing plate. The magnetic resonance imaging apparatus according to claim 1.
The substrate is divided into two or more parts together with the reinforcing plate, and each of the substrates is electrically connected,
The magnetic resonance imaging apparatus, wherein an edge of each substrate is fixed to the RF coil. The magnetic resonance imaging apparatus according to claim 2.
The substrate is divided into two or more parts together with the reinforcing plate and the support member, and each of the substrates is electrically connected,
The magnetic resonance imaging apparatus, wherein an edge of each substrate is fixed to the RF coil. The magnetic resonance imaging apparatus according to claim 4.
The substrate is divided into two or more with the support plate, and the substrates are electrically connected,
The magnetic resonance imaging apparatus, wherein an edge of each substrate is fixed to the RF coil. The magnetic resonance imaging apparatus according to any one of claims 1 to 3, or 6 to 8.
Magnetic resonance imaging characterized in that L ² / h is 500 mm or less, where Lmm is the distance between the fixing portions of the substrate to the RF coil and hmm is the combined thickness of the substrate and the reinforcing plate. apparatus. The magnetic resonance imaging apparatus according to any one of claims 4, 5, or 9,
A magnetic resonance imaging apparatus, wherein L ² / h is 500 mm or less, where Lmm is the interval between the fixed portions of the substrate and hmm is the thickness of the substrate. The magnetic resonance imaging apparatus according to claim 3, claim 5, or claim 6 to claim 9,
The edge part to which the said board | substrate is fixed is four places of a corner part. The magnetic resonance imaging apparatus characterized by the above-mentioned. The magnetic resonance imaging apparatus according to any one of claims 1 to 12,
The magnetic field resonance imaging apparatus, wherein the gradient magnetic field coil has a horizontally long flat shape on an inner surface of a cross section perpendicular to a central axis thereof.

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