Rotatable magnet methods and apparatus for a magnetic resonance imaging system

1. A magnetic resonance imaging system comprising:

a B 0 magnet configured to produce a B 0 magnetic field for the magnetic resonance imaging system; and

a positioning member coupled to the B 0 magnet and configured to allow the B 0 magnet to be manually rotated to a plurality of positions, each of the plurality of positions placing the B 0 magnet at a different angle, wherein the positioning member comprises:

at least one member to hold the B 0 magnet at a selected one of the plurality of positions; and

at least one manual release mechanism that, when engaged, releases the at least one member and allows a user to manually rotate the B 0 magnet to a different one of the plurality of positions.

2. The magnetic resonance imaging system of claim 1 , wherein the positioning member is coupled to the B 0 magnet such that the B 0 magnet is rotated substantially about its center of mass so that the center of mass of the B 0 magnet remains in substantially a same location at each of the plurality of positions.

3. The magnetic resonance imaging system of claim 1 , wherein the member comprises a pin and plurality of holes corresponding to respective ones of the plurality of positions, and wherein the at least one manual release mechanism, when operated by the user, releases the pin from one of the plurality of holes so that the pin can be moved to another of the plurality of holes to lock the positioning member at a different one of the plurality of positions.

4. The magnetic resonance imaging system of claim 1 , wherein each of the plurality of positions corresponds to a tilt of the B 0 magnet that produces a respective different incline of a surface configured to support anatomy of a patient within an imaging region of the magnetic resonance imaging system.

5. The magnetic resonance imaging system of claim 4 , wherein each of the plurality of positions corresponds to a respective different incline of the surface, and wherein the plurality of positions includes a position corresponding to the surface being horizontal.

6. The magnetic resonance imaging system of claim 1 , wherein the B 0 magnet comprises:

at least one first B 0 magnet to produce a magnetic field to contribute to the B 0 magnetic field for the magnetic resonance imaging system; and

at least one second B 0 magnet to produce a magnetic field to contribute to the B 0 magnetic field for the magnetic resonance imaging system, wherein the at least one first B 0 magnet and the at least one second B 0 magnet are arranged relative to one another so that an imaging region is provided there between,

wherein the magnetic resonance imaging system further comprises a yoke, magnetically coupled to the at least one first B 0 magnet and the at least one second B 0 magnet, to capture and direct at least some of the magnetic field generated by the at least one first B 0 magnet and the at least one second B 0 magnet to increase the magnetic flux density within the imaging region, and

wherein the positioning member is coupled to the yoke such that the positioning member tilts the yoke along with the B 0 magnet.

7. The magnetic resonance imaging system of claim 6 , wherein the B 0 magnet and the yoke together weigh less than 600 kilograms.

8. The magnetic resonance imaging system of claim 6 , wherein the B 0 magnet and the yoke together weigh less than 500 kilograms.

9. The magnetic resonance imaging system of claim 6 , wherein the B 0 magnet and the yoke together weigh less than or equal to approximately 600 kilograms and greater than or equal to approximately 450 kilograms.

10. The magnetic resonance imaging system of claim 6 , further comprising:

a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging, the magnetics system comprising:

the B 0 magnet; and

a plurality of gradient coils configured to, when operated, generate magnetic fields to provide spatial encoding of emitted magnetic resonance signals;

a power system comprising one or more power components configured to provide power to the magnetics system to operate the magnetic resonance imaging system to perform image acquisition; and

a base that supports the positioning member and the magnetics system and houses the power system.

11. The magnetic resonance imaging system of claim 10 , wherein the positioning member has a first portion fixedly coupled to the base and a second portion rotatably coupled to the B 0 magnet such that, when operated, the positioning member rotates the B 0 magnet without rotating the base.

12. The magnetic resonance imaging system of claim 10 , wherein the base comprises at least one conveyance mechanism allowing the magnetic resonance imaging system to be transported to desired locations.

13. The magnetic resonance imaging system of claim 10 , wherein the base has a maximum horizontal dimension of less than or equal to approximately 50 inches.

14. The magnetic resonance imaging system of claim 10 , wherein the base has a maximum horizontal dimension of less than or equal to approximately 40 inches.

15. The magnetic resonance imaging system of claim 10 , wherein the base has a maximum horizontal dimension of less than or equal to approximately 35 inches.

16. The magnetic resonance imaging system of claim 10 , wherein the base has a maximum horizontal dimension of less than or equal to approximately 30 inches.

17. The magnetic resonance imaging system of claim 1 , wherein the B 0 magnet is configured to produce a B 0 magnetic field at a field strength of less than or equal to approximately 0.2 T and greater than or equal to approximately 0.1 T.

18. The magnetic resonance imaging system of claim 1 , wherein the B 0 magnet is configured to produce a B 0 magnetic field at a field strength of less than or equal to approximately 0.1 T and greater than or equal to approximately 50 mT.

19. The magnetic resonance imaging system of claim 1 , wherein the B 0 magnet is configured to produce a B 0 magnetic field at a field strength of less than or equal to approximately 50 mT and greater than or equal to approximately 20 mT.