Producing a radiation treatment plan

1. A device for producing a radiation treatment plan, the device comprising:

a computer unit having an input device and an output device, the computer unit being operable to:

specify a dataset in which an object, which is to be irradiated, is represented,

determine a target volume to be irradiated within the object,

ascertain an index identifying a density heterogeneity for a region that will be struck by a planned treatment beam, and

determine as a function of the ascertained index a safety margin for the target volume to be irradiated.

2. The device as claimed in claim 1 , wherein the computer unit is operable to establish the irradiating of the target volume by a multiplicity of particle beams to be applied successively, the region including an area that will be struck by a plurality of the multiplicity of particle beams to be applied successively.

3. The device as claimed in claim 1 , wherein the region includes an area situated in an entry channel of the planned treatment beam in front of the target volume in the beam direction.

4. The device as claimed in claim 1 , wherein the region includes an entire area that will be struck by the planned treatment beam.

5. The device as claimed in claim 1 , wherein the computer unit is operable to select an entry angle of the planned treatment beam as a function of the index.

6. The device as claimed in claim 1 , wherein the computer unit is operable to check a dose distribution defined by the planned treatment beam for dose distribution robustness with respect to spatial imprecision in dose depositing.

7. A device for producing a radiation treatment plan, the device comprising a computer unit having an input device and an output device, the computer unit being operable to:

specify a dataset in which an object, which is to be irradiated, is represented,

determine a target volume that is to be irradiated within the object,

specify at least two irradiation fields with which the target volume will be irradiated from in each case a different direction,

ascertain for each of the at least two irradiation fields an index that identifies a density homogeneity for a region which will be struck during planned irradiating with the respective irradiating field, and

determine a weighting for the at least two irradiation fields as a function of the index ascertained.

8. The device as claimed in claim 7 , wherein the computer unit is operable to establish the irradiating of the target volume by a multiplicity of particle beams to be applied successively, the region including an area that will be struck by a plurality of the particle beams to be applied successively for the irradiation field.

9. The device as claimed in claim 7 , wherein the region for one of the at least two irradiation fields includes an area that is situated in an entry channel of a treatment beam in front of the target volume in the treatment beam direction.

10. The device as claimed in claim 7 , wherein the region for one of the at least two irradiation fields includes an entire area that will be struck by a treatment beam.

11. The device as claimed in claim 7 , wherein the weighting, an entry angle and a safety margin are selected for at least one of the at least two irradiation fields as a function of the indices ascertained.

12. The device as claimed in claim 7 , wherein the computer unit is operable to check a dose distribution defined by the planned irradiating for one of the at least two irradiation fields for dose distribution robustness with respect to spatial imprecision in dose depositing.

13. The device as claimed in claim 7 , wherein an entry angle or a safety margin is selected for at least one of the at least two irradiation fields as a function of the indices ascertained.

14. A method for producing a radiation treatment plan, the method comprising:

specifying a dataset in which an object to be irradiated is represented,

determining a target volume to be irradiated within the object,

ascertaining an index identifying a density heterogeneity for a region that will be struck by a planned treatment beam, and

determining as a function of the ascertained index a safety margin for the target volume.

15. A method for producing a radiation treatment plan, the method comprising:

specifying a dataset in which an object to be irradiated is represented,

determining a target volume to be irradiated within the object, specifying at least two irradiation fields with which the target volume will be irradiated from in each case a different direction,

ascertaining for each of the at least two irradiation fields an index that identifies a density homogeneity for a region which will be struck during planned irradiating with the respective irradiating field, and

determining a weighting for the at least two irradiating fields as a function of the indices ascertained.