Gradient coil unit and magnetic resonance imaging apparatus
A gradient coil unit includes a tubular gradient coil and support structures. The tubular gradient coil is configured to apply a gradient magnetic field to an imaging region of magnetic resonance imaging. The support structures are fixed to plural positions of the gradient coil. The support structures are configured to hold the gradient coil on a tubular magnet by applying pressing forces on positions of an edge inside a wall forming the magnet. The pressing forces each has a component in a central axis direction of the magnet. Further, according to another embodiment, a magnetic resonance imaging apparatus includes the above mentioned gradient coil unit, a static field magnet and at least one radio frequency coil configured to perform magnetic resonance imaging of an object.
1. A gradient coil unit comprising:
a tubular gradient coil configured to apply a gradient magnetic field to an imaging region of a magnetic resonance imaging system; and
support structures, fixed to plural positions of said gradient coil, configured to hold said gradient coil on a tubular magnet by applying pressing forces on positions of an edge inside a wall forming the magnet, the pressing forces each having a component in a central axis direction of the magnet.
2. A gradient coil unit of claim 1 , wherein at least one of said support structures is configured to apply a pressing force in the central axis direction of the magnet.
3. A gradient coil unit of claim 1 , wherein at least one of said support structures is configured to apply a pressing force at an inclined angle from the central axis direction of the magnet.
4. A gradient coil unit of claim 1 , wherein at least one of said support structures is configured to apply a pressing force on an end part of at least one of an internal cylinder member and an end face which form the magnet.
5. A gradient coil unit of claim 1 ,
wherein at least one of said support structures is configured to apply a pulling force on said gradient coil, the pulling force having a component in the central axis direction.
6. A gradient coil unit of claim 1 , wherein said support structures are configured to adjust a position of said gradient coil.
7. A gradient coil unit of claim 1 ,
wherein at least one of said support structures is configured to include a vibration-proof material in at least a part thereof.
8. A gradient coil unit of claim 1 ,
wherein a member of at least one of said support structures includes a non-conductive material, contacting the magnet.
9. A gradient coil unit of claim 1 , wherein at least one of said support structures has:
a first member fixed to a side of said gradient coil;
a second member contacting with the edge or connected with the edge of the magnet; and
a movable structure configured to adjust a position of said first member, with respect to said second member, at least in the central axis direction.
10. A gradient coil unit of claim 1 , wherein at least one of said support structures has:
a first member fixed to a side of said gradient coil;
a second member contacting with the edge or connected with the edge of the magnet;
a female screw formed in said first member side; and
a male screw fastened with said female screw and having a curved contact face at a tip, the contact face being contacting with said second member.
11. A gradient coil unit of claim 1 , wherein at least one of said support structures has:
a first member fixed to said gradient coil side and having an elastically deformable portion;
a second member contacting with the edge or connected with the edge;
a female screw formed in said first member side; and
a male screw fastened with said female screw and contacting with said second member.
12. A gradient coil unit of claim 1 , wherein at least one of said support structures has:
a first member fixed to a side of said gradient coil;
a second member contacting with the edge or connected with the edge of said magnet;
a female screw formed in said first member; and
a male screw fastened with said female screw and contacting said second member,
wherein said first member has an elongated hole disposed to receive said male screw therethrough.
13. A magnetic resonance imaging apparatus comprising: a gradient coil unit of claim 1 , a static field magnet and at least one radio frequency coil configured to perform magnetic resonance imaging of an object.