Magnetic resonance imaging apparatus
A magnetic resonance imaging apparatus includes: a magnetostatic field magnet formed in the shape of a substantially circular cylinder; a gradient coil formed in the shape of a substantially circular cylinder on the inside of the magnetostatic field magnet; a cylindrical part that is formed in the shape of a substantially circular cylinder on the inside of the gradient coil and includes at least one selected from a sound absorbing material layer and a sound blocking material layer; and a ring part that is substantially ring-shaped, covers the space formed between the magnetostatic field magnet and the cylindrical part on at least one end face of a magnet structure being formed in the shape of a substantially circular cylinder and including the magnetostatic field magnet, the gradient coil, and the cylindrical part, and includes at least one selected from an sound absorbing material layer and a sound blocking material layer.
1. A magnetic resonance imaging (MRI) apparatus comprising:
a magnetostatic field magnet formed in a shape of a substantially circular cylinder;
a gradient coil also formed in a shape of a substantially circular cylinder and concentrically disposed inside the magnetostatic field magnet;
a cylindrical part that is also formed in a shape of a substantially circular cylinder and disposed concentrically inside the gradient coil, said cylindrical part including a first structure of layered members, the first structure having at least one layer made of a sound absorbing material that absorbs sound and a layer made of a sound blocking material that blocks sound; and
a ring part that is substantially ring-shaped, said ring part being configured to cover a space formed between the magnetostatic field magnet and the cylindrical part on at least one end face of the magnetostatic field magnet, said ring part including a second structure of layered members, the second structure having at least one layer made of the sound absorbing material and a layer made of the sound blocking material, the ring part including at least one of an outer circumferential part and an inner circumferential part:
the outer circumferential part being attached to an end face of the magnetostatic field magnet via a first sealing member, a distance between the outer circumferential part and the end face of the magnetostatic field magnet being shorter than a thickness of the first sealing member in an uncompressed state and longer than the thickness of the first sealing member in a fully compressed state; and
the inner circumferential part being attached to an end face of the cylindrical part via a second sealing member, a distance between the inner circumferential part and the end face of the cylindrical part being shorter than a thickness of the second sealing member in an uncompressed state and longer than the thickness of the second sealing member in a fully compressed state.
2. The magnetic resonance imaging apparatus according to claim 1 , wherein the ring part has a sealing member provided along each of inner and outer circumferences of a plane that is in contact with the end face of the magnetostatic field magnet, so that the ring part is attached to the magnetostatic field magnet via the sealing members.
3. The magnetic resonance imaging apparatus according to claim 2 , wherein the sealing members are formed with either closed-cell bubbles or semi-closed-cell bubbles.
4. The magnetic resonance imaging apparatus according to claim 1 , further comprising: a gantry cover that is substantially ring-shaped so as to have a diameter that is substantially equal to a diameter of the ring part.
5. The magnetic resonance imaging apparatus according to claim 1 , wherein
the magnetostatic field magnet includes a fixing unit configured to fix the ring part on the end face of the magnetostatic field magnet, and
the fixing unit is rotatably attached to the magnetostatic field magnet while using a predetermined point as a supporting point.
6. The magnetic resonance imaging apparatus according to claim 1 , wherein the ring part has a resilient member provided along each of inner and outer circumferences of a plane that is in contact with the end face of the magnetostatic field magnet, so that the ring part is attached to the magnetostatic field magnet via the resilient members.
7. The magnetic resonance imaging apparatus according to claim 1 , wherein, when including multiple layers made of the sound blocking material, the cylindrical part includes a layer made of thermosetting resin as at least one of the multiple layers made of the sound blocking material.
8. The magnetic resonance imaging apparatus according to claim 1 , wherein the cylindrical part includes a non-metallic layer having a predetermined strength, as an innermost layer.
9. The magnetic resonance imaging apparatus according to claim 1 , wherein layers in the cylindrical part are connected to one another as a result of either adhering or fastening together the layers included in the cylindrical part.
10. The magnetic resonance imaging apparatus according to claim 1 , wherein, when resin is shaped as the sound blocking material included in the cylindrical part, the resin is a different material from thermosetting resin used in a shaping process of the cylindrical part.
11. The magnetic resonance imaging apparatus according to claim 1 , further comprising:
a second ring part that is substantially ring-shaped, that is configured to cover a space formed between the magnetostatic field magnet and the cylindrical part on at least one end face of the magnetostatic field magnet, said second ring part being formed in a shape of a substantially circular cylinder that includes at least one layer made of the sound blocking material.
12. The magnetic resonance imaging apparatus according to claim 11 , further comprising: a fixing unit configured to fix the ring part to the magnetostatic field magnet and the cylindrical part on the end face.
13. The magnetic resonance imaging apparatus according to claim 11 , wherein, when including multiple layers made of the sound blocking material, the ring part includes a layer made of thermosetting resin as at least one of the multiple layers made of the sound blocking material.
14. The magnetic resonance imaging apparatus according to claim 11 , wherein the ring part includes a non-metallic layer having a predetermined strength, as an outermost layer.
15. The magnetic resonance imaging apparatus according to claim 11 , further comprising: a ring-shaped gantry cover that is formed to be substantially ring-shaped on an outside of the ring part and that has a minimum possible size for covering the ring part.
16. The magnetic resonance imaging apparatus according to claim 11 , wherein the ring part is formed to have one or more recesses and projections conforming to a recess/projection structure provided on the end face of the gradient coil.
17. The magnetic resonance imaging apparatus according to claim 11 , wherein the ring part is formed by shaping thermosetting resin into one or more layers including at least one layer made of the sound absorbing material.
18. The magnetic resonance imaging apparatus according to claim 17 , wherein, when resin is shaped as the sound blocking material included in the ring part, the resin is a different material from thermosetting resin used in a shaping process of the ring part.
19. The magnetic resonance imaging apparatus according to claim 1 , wherein the ring part has a sealing member provided along each of inner and outer circumferences of a plane that is in contact with the magnetostatic field magnet and the cylindrical part.