Radiotherapeutic apparatus

1. A radiotherapeutic system comprising:

a patient support;

a magnetic resonance examination system with magnetic coils disposed around the patient support for creating a magnetic field therewithin and configured for detecting magnetic resonance signals and deriving images therefrom;

a radiotherapeutic radiation source producing a beam of radiotherapeutic radiation directed toward the patient support and mounted on a rotatable support thereby to rotate the radiation source around the patient support, and

a slip ring located around the patient support and configured to convey electrical power provided from a base to the radiation source, wherein the slip ring includes at least one electrical interruption formed by at least one non-conductive section in the slip ring, and the rotatable support includes at least one brush contact arranged to contact the slip ring, wherein the at least one electrical interruption provides only one path of current along the slip ring from the base to which current is being supplied to the brush so as to prevent a stray magnetic field generated by rotation of the rotatable support around the slip ring from interfering with images produced by the magnetic resonance examination system;

a control apparatus coupled to the radiotherapeutic radiation source, wherein the control apparatus is configured to control the radiotherapeutic radiation source and to perform at least one of:

i. de-activating the magnetic resonance examination system while the at least one brush contact is crossing the at least one non-conductive section, and

ii. preventing the magnetic resonance examination system from acquiring or using imaging data while the at least one brush contact is crossing the at least one non-conductive section.

2. The radiotherapeutic system according to claim 1 , wherein the at least one non-conductive section is an air gap.

3. The radiotherapeutic system according to claim 1 , wherein the at least one non-conductive section is a break filled with an electrical insulator.

4. The radiotherapeutic system according to claim 1 , wherein the at least one brush contact has a length in a direction tangential to the slip ring greater than the length of the at least one non-conducting section therein.

5. The radiotherapeutic system according to claim 1 , wherein the at least one brush contact has a length in a direction tangential to the slip ring smaller than the length of the at least one non-conducting section therein.

6. The radiotherapeutic system according to claim 1 , wherein the radiation source is a linear accelerator.

7. The radiotherapeutic system according to claim 1 , wherein the slip ring is arranged to rotate with the rotatable support, and further comprising two or more rotationally stationary brush contacts, arranged to contact the slip ring.

8. The radiotherapeutic system according to claim 7 , wherein the two or more rotationally stationary brush contacts are arranged a greater distance apart than the length of said at least one non-conductive section.

9. The radiotherapeutic system according to claim 1 , wherein the slip ring comprises a plurality of electrical interruptions defining a plurality of electrically separate slip ring segments.

10. The radiotherapeutic system according to claim 9 , wherein each slip ring segment is separately and selectively coupled to a power source.

11. The radiotherapeutic system according to claim 1 , wherein the slip ring comprises at least two switches, forming the electrical interruption for selectively separating the slip ring into at least two electrically separate arc segments.

12. The radiotherapeutic system according to claim 11 , wherein the magnetic resonance examination system is further configured to control the at least two switches according to a position of the rotatable support in relation to the slip ring.

13. The radiotherapeutic system according to claim 12 wherein the magnetic resonance examination system is configured to control the at least two switches such that the radiation source is continuously powered regardless of the position of the rotatable support in relation to the slip ring.

14. A treatment planning apparatus configured to produce a treatment plan configured for a radiotherapeutic system, wherein the treatment planning apparatus comprises the radiotherapeutic system with a patient support, a magnetic resonance examination system with magnetic coils disposed around the patient support for creating a magnetic field therewithin, a radiotherapeutic radiation source producing a beam of radiotherapeutic radiation directed toward the patient support and mounted on a rotatable support thereby to rotate the radiation source around the patient support, and a slip ring located around the patient support and configured to convey electrical power provided from a base to the radiation source, wherein the slip ring includes at least one electrical interruption formed by at least one non-conductive section in the slip ring, and the rotatable support includes at least one brush contact, arranged to contact the slip ring, wherein the at least one electrical interruption provides only one path of current along the slip ring from the base to which current is being supplied to the brush so as to prevent a stray magnetic field generated by rotation of the rotatable support around the slip ring from interfering with images produced by the magnetic resonance examination system; a processing circuitry for receiving clinical parameters

including at least imaging data of a patient in which areas for treatment have been identified, and geometric constraints including at least the location of the at least one electrical interruption in the slip ring;

wherein the processing circuitry further configured to generate a treatment plan based at least on said clinical parameters and said geometric constraints, in which the operation of said radiation source is suppressed when the position of said rotatable source corresponds to the location of the at least one electrical interruption; and

wherein the processing circuitry further configured to output said treatment plan.

15. A method of generating a treatment plan configured for a radiotherapeutic system comprising a patient support, a magnetic resonance examination system with magnetic coils disposed around the patient support for creating a magnetic field therewithin, a radiotherapeutic radiation source configured to produce a beam of radiotherapeutic radiation directed toward the patient support and mounted on a rotatable support thereby to rotate the radiation source around the patient support, and a slip ring located around the patient support and configured to convey electrical power provided from a base to the radiation source, wherein the slip ring includes at least one electrical interruption formed by at least one non-conductive section in the slip ring, and the rotatable support includes at least one brush contact arranged to contact the slip ring, wherein the at least one electrical interruption provides only one path of current along the slip ring from the base to which current is being supplied to the brush so as to prevent a stray magnetic field generated by rotation of the rotatable support around the slip ring from interfering with images produced by the magnetic resonance examination system, the method comprising:

receiving clinical parameters, including at least imaging data of a patient in which areas for treatment have been identified, and geometric constraints including at least the location of the at least one electrical interruption in the slip ring;

generating a treatment plan based at least on said clinical parameters and said geometric constraints, in which the operation of said radiation source is suppressed when the position of said rotatable source corresponds to the location of the at least one electrical interruption; and

outputting said treatment plan.