Flattened gradient coil for MRI systems
A gradient coil and an insert gradient coil for a magnetic resonance imaging system include a primary coil. The primary coil includes an upper primary coil portion and a lower primary coil portion, the lower primary coil portion being less curved in cross-section than the upper primary coil portion. The gradient coil also includes a shielding coil disposed outside of the primary coil. The shielding coil includes an upper shielding coil portion and a lower shielding coil portion, the lower shielding coil portion being less curved in cross-section than the upper shielding coil portion.
1. A gradient coil for a magnetic resonance imaging system, said gradient coil comprising:
a primary coil comprising an upper primary coil portion and a lower primary coil portion, said lower primary coil portion being less curved in cross-section than the upper primary coil portion; and
a shielding coil disposed outside of the primary coil; said shielding coil comprising an upper shielding coil portion and a lower shielding coil portion, said lower shielding coil portion being less curved in cross-section than the upper shielding coil portion.
2. The gradient coil of claim 1 , wherein said primary coil defines a patient bore and a longitudinal axis.
3. The gradient coil of claim 2 , wherein the cross-section is perpendicular to the longitudinal axis.
4. The gradient coil of claim 1 , wherein said primary coil comprises an asymmetric primary coil configured to create a field-of-view that is offset in a z-direction from a center of the gradient coil.
5. The gradient coil of claim 1 , wherein said primary coil and said shielding coil are configured to substantially cancel any net thrust force caused by operating said gradient coil.
6. The gradient coil of claim 1 , wherein said primary coil and said shielding coil are configured to substantially cancel any net torque caused by operating said gradient coil.
7. The gradient coil of claim 1 , wherein at least one of said primary coil and said shielding coil comprises a hollow conductor configured to transport a coolant.
8. The gradient coil of claim 1 , further comprising a conduit disposed within the primary coil, said conduit configured to transport a coolant.
9. The gradient coil of claim 1 , wherein said lower primary coil portion comprises fewer turns than said upper primary coil portion.
10. The gradient coil of claim 1 , wherein said lower shield coil portion comprises fewer turns than said upper shield coil portion.
11. The gradient coil of claim 1 , further comprising an RF shield disposed inside of the primary coil.
12. A gradient coil for a magnetic resonance imaging system, said gradient coil comprising:
a primary coil defining a patient bore, said primary coil comprising a first shape that is larger in an x-direction than in a y-direction; and
a shielding coil disposed outside of the primary coil, said shielding coil configured to reduce the magnetic field created by the primary coil in a region outside of the shielding coil, said shielding coil comprising a second shape that is larger in the x-direction than in the y-direction.
13. The gradient coil of claim 12 , wherein said shielding coil is separated from said primary coil by a substantially uniform distance.
14. The gradient coil of claim 12 , wherein said shielding coil is closer to said primary coil at a lower side of the gradient coil.
15. The gradient coil of claim 12 , wherein the primary coil comprises an asymmetric primary coil configured to create a field-of-view that is offset from a center of the gradient coil in a z-direction.
16. The gradient coil of claim 12 , wherein said primary coil and said shielding coil are electrically interconnected.
17. An insert gradient coil for a magnetic resonance imaging system, said insert gradient coil comprising:
a primary coil comprising an upper primary coil portion and a lower primary coil portion, said lower primary coil portion being less curved in cross-section than the upper primary coil portion; and
a shielding coil disposed outside of the primary coil; said shielding coil comprising an upper shielding coil portion and a lower shielding coil portion, said lower shielding coil portion being less curved in cross-section than the upper shielding coil portion.
18. The insert gradient coil of claim 17 , wherein the lower shielding coil portion comprises a shape defining a substantially flat bottom surface.
19. The insert gradient coil of claim 18 , wherein said insert gradient coil is adapted to receive a patient's head.
20. The insert gradient coil of claim 19 , wherein the primary coil and the shielding coil are shaped to form an upper lobe and a lower lobe on a patient receiving end of the insert gradient coil, said upper lobe and said lower lobe configured to accommodate a patient's shoulders.
21. The insert gradient coil of claim 18 , further comprising a member attached to the outside of the lower shielding portion, said member adapted to interface with a rail of the magnetic resonance imaging system.
22. The insert gradient coil of claim 17 , wherein said gradient coil is adapted to be positioned on top of a patient bed within the magnetic resonance imaging system.