Local SAR behavior of MRI transmission coils by use of orthogonal loop antennas

1. A local coil for a magnetic resonance imaging system, the local coil comprising:

at least one former antenna and at least one further antenna,

wherein the at least one former antenna is arranged orthogonally with respect to the at least one further antenna, and

wherein the local coil is arranged in a bore of a magnetic resonance imaging system such that the at least one further antenna of the local coil is arranged so that a surface normal of the at least one further antenna is arranged parallel to a direction of a basic magnetic field in the bore of the magnetic resonance imaging system.

2. The local coil of claim 1 , wherein the at least one former antenna comprises a plurality of former antennas, and the at least one further antenna comprises a plurality of further antennas, and

wherein the plurality of former antennas are arranged orthogonally with respect to the plurality of further antennas.

3. The local coil of claim 1 , wherein the at least one former antenna is arranged orthogonally with respect to the at least one further antenna in order to enable an optimization of a local SAR behavior of the local coil.

4. The local coil of claim 1 , wherein some or all antennas of the at least one former antenna and the at least one further antenna are loop antennas, and

wherein an area in which the at least one former antenna is arranged is orthogonal with respect to an area in which the at least one further antenna is arranged.

5. The local coil of claim 1 , wherein the at least one former antenna is arranged in a plane having a surface normal that is arranged perpendicularly or horizontally and perpendicularly to a longitudinal direction of a patient couch, to a longitudinal direction of a bore of the magnetic resonance imaging system during imaging in the bore of the magnetic resonance imaging system, or a combination thereof.

6. The local coil of claim 1 , wherein the at least one further antenna of the local coil is arranged in a plane having a surface normal that is arranged horizontally and in a longitudinal direction of a patient couch, with respect to a longitudinal direction of a bore of the magnetic resonance imaging system during imaging in the bore of the magnetic resonance imaging system, or a combination thereof.

7. The local coil of claim 1 , wherein some or all antennas of the at least one former antenna and the at least one further antenna are also receiving antennas, are connected to a receiving device of the magnetic resonance imaging system, or a combination thereof.

8. The local coil of claim 1 , wherein the local coil is a head coil comprising the at least one former antenna and the at least one further antenna.

9. The local coil of claim 1 , wherein the local coil is a spinal column coil comprising the at least one former antenna and the at least one further antenna.

10. The local coil of claim 1 , wherein the local coil comprises an array, the array comprising the at least one former antenna and the at least one further antenna.

11. The local coil of claim 1 , further comprising a plurality of arrays, each array of the plurality of arrays comprising at least one former antenna and at least one further antenna,

wherein the at least one former antenna of the respective array is arranged orthogonally with respect to the at least one further antenna of the respective array.

12. The local coil of claim 1 , further comprising a plurality of arrays, each array of the plurality of arrays comprising exactly one former antenna and exactly one further antenna,

wherein the one former antenna is arranged orthogonally with respect to the one further antenna.

13. The local coil of claim 1 , further comprising a plurality of arrays, each array of the plurality of arrays comprising exactly one former antenna and a plurality of further antennas,

wherein the one former antenna is arranged orthogonally with respect to the plurality of further antennas.

14. The local coil of claim 1 , wherein direct or direct and next but one neighbors of the at least one former antenna are decoupled from one another.

15. The local coil of claim 1 , wherein direct or direct and next but one neighbors of the at least one further antenna are decoupled from one another.

16. The local coil of claim 1 , wherein the at least one former antenna, the at least one further antenna, or the at least one former antenna and the at least one further antenna of the local coil are provided as transmitting antenna for transmission, are connectable to a transmitting arrangement of the magnetic resonance imaging system, or a combination thereof.

17. The local coil of claim 16 , wherein the at least one former antenna, the at least one further antenna, or the at least one former antenna and the at least one further antenna of the local coil are connectable to an amplifier, a splitter, or the amplifier and the splitter of the magnetic resonance imaging system.

18. The local coil of claim 1 , wherein all former antennas of the at least one former antenna and all further antennas of the at least further antenna are driven individually in each case by a transmitter.

19. The local coil of claim 1 , wherein in each case one former antenna and at least one further antenna are driven jointly by a transmitter.

20. The local coil of claim 1 , wherein the at least one former antenna and the at least one further antenna are driven by fewer transmitters than former antennas are provided, and

wherein transmission energy is divided via fixed or adjustable passive networks.

21. The local coil of claim 1 , wherein all former antennas of the at least one former antenna and all further antennas of the at least one further antenna are driven together by overall only one transmitter, and

wherein transmission energy is divided via a distribution network.

22. The local coil of claim 21 , wherein the transmitter comprises an amplifier connected to a device for generating signals to be transmitted, in particular radiofrequency signals.

23. The local coil of claim 22 , wherein the signals are radio-frequency signals.

24. A magnetic resonance imaging system comprising:

a local coil comprising:

at least one former antenna and at least one further antenna,

wherein the at least one former antenna is arranged orthogonally with respect to the at least one further antenna, and

wherein the local coil is arranged in a bore of a magnetic resonance imaging system such that the at least one further antenna of the local coil is arranged so that a surface normal of the at least one further antenna is arranged parallel to a direction of a basic magnetic field in the bore of the magnetic resonance imaging system.