Determining an irradiation plan for a particle irradiation unit

1. A method for determining an irradiation plan for a particle irradiation unit, wherein the particle irradiation unit is used to irradiate a target volume within an examination object with a particle beam depending on the irradiation plan, the method comprising:

prescribing the target volume and a predetermined dose distribution; and

determining the irradiation plan in order to apply the particle beam in accordance with the predetermined dose distribution in the target volume, the target volume comprising a plurality of isoenergy layers,

wherein a boundary condition is prescribed for at least one of the isoenergy layers,

wherein the irradiation plan is determined such that the boundary condition for the at least one isoenergy layer is observed,

wherein the boundary condition comprises at least one of the following conditions:

a minimum peak energy,

a maximum peak energy,

a minimum number of raster points,

a minimum overall number of particles,

a minimum overall dose,

a minimum dose contribution to an overall dose to be applied,

a minimum contribution to a target function calculated for determining the irradiation plan, and

a minimum dose compensation error, wherein the dose compensation error specifies an error that occurs as a result of the non-irradiation of the respective isoenergy layer despite corresponding compensation by the irradiated isoenergy layers, and

wherein at least one individual boundary condition is prescribed for each isoenergy layer of the plurality of isoenergy layers.

2. The method as claimed in claim 1 , wherein a same condition is prescribed for each isoenergy layer in respect of at least one of the conditions.

3. The method as claimed in claim 1 , further comprising:

determining a further irradiation plan,

wherein, for the determining of the further irradiation plan, the boundary condition is lifted for at least one specific one of the isoenergy layers, in which no particles are applied in accordance with the irradiation plan since the boundary condition is broken, such that the further irradiation plan is determined without there being a restriction by the boundary condition in respect of the at least one specific isoenergy layer, and

wherein a plan quality of the irradiation plan depending on the dose distribution is compared to a further plan quality of the further irradiation plan depending on the dose distribution for evaluating the irradiation plan.

4. The method as claimed in claim 1 , wherein a dose distribution is determined,

wherein the dose distribution is applied in accordance with the irradiation plan, and

wherein the dose distribution is compared to the predetermined dose distribution for evaluating the irradiation plan.

5. The method as claimed in claim 4 , wherein at least one planning result of a group of planning results for the irradiation plan and for a further irradiation plan is determined for evaluating the irradiation plan, and

wherein the group of planning results comprises:

a dose/volume histogram,

a specification of how much of the dose is applied in the target volume according to the irradiation plan, and

a specification of how much of the dose is applied in at least one organ at risk of the examination object according to the irradiation plan.

6. The method as claimed in claim 1 , wherein the target function, which is calculated for determining the irradiation plan, comprises a penalty term, and

wherein the penalty term reduces a quality of a function value to be optimized of the target function further as a distance in accordance with the irradiation plan to the respective condition decreases.

7. The method as claimed in claim 1 , wherein a preliminary irradiation plan is determined in order to apply the particle beam in the target volume in accordance with the predetermined dose distribution, and

wherein the boundary condition is prescribed depending on the preliminary irradiation plan.

8. A device for determining an irradiation plan for a particle irradiation unit, wherein the particle irradiation unit is used to irradiate a target volume within an examination object with a particle beam depending on the irradiation plan, the device comprising:

an input;

a computer; and

an output, wherein the target volume and a predetermined dose distribution are prescribable for the device by the input,

wherein the computer is configured to determine the irradiation plan in order to apply the particle beam in the target volume comprising a plurality of isoenergy layers, in accordance with the predetermined dose distribution,

wherein the output is configured to output the irradiation plan,

wherein a boundary condition for at least one of the isoenergy layers is prescribable for the device by the input, where the computer is configured to additionally determine the irradiation plan such that the boundary condition for the at least one isoenergy layer is observed,

wherein the boundary condition comprises at least one of the following conditions:

a minimum peak energy,

a maximum peak energy,

a minimum number of raster points,

a minimum overall number of particles,

a minimum overall dose,

a minimum dose contribution to an overall dose to be applied,

a minimum contribution to a target function calculated for determining the irradiation plan, and

a minimum dose compensation error, wherein the dose compensation error specifies an error that occurs as a result of the non-irradiation of the respective isoenergy layer despite corresponding compensation by the irradiated isoenergy layers, and

wherein at least one individual boundary condition is prescribed for each isoenergy layer of the plurality of isoenergy layers.

9. A computer program product comprising a non-transitory computer-readable storage medium that stores instructions executable by a control apparatus of a particle irradiation unit, the instructions comprising:

prescribing a target volume and a predetermined dose distribution; and

determining an irradiation plan in order to apply a particle beam in accordance with the predetermined dose distribution in the target volume, the target volume comprising a plurality of isoenergy layers,

wherein a boundary condition is prescribed for at least one of the isoenergy layers,

wherein the irradiation plan is determined such that the boundary condition for the at least one isoenergy layer is observed,

wherein the boundary condition comprises at least one of the following conditions:

a minimum peak energy,

a maximum peak energy,

a minimum number of raster points,

a minimum overall number of particles,

a minimum overall dose,

a minimum dose contribution to an overall dose to be applied,

a minimum contribution to a target function calculated for determining the irradiation plan, and

a minimum dose compensation error, wherein the dose compensation error specifies an error that occurs as a result of the non-irradiation of the respective isoenergy layer despite corresponding compensation by the irradiated isoenergy layers, and

wherein at least one individual boundary condition is prescribed for each isoenergy layer of the plurality of isoenergy layers.

10. An electronically readable data medium with electronically readable control information stored thereon which is configured in such a way that, when the data medium is used in a control apparatus of a particle irradiation unit, the data medium is configured to at least perform:

prescribe a target volume and a predetermined dose distribution; and

determine an irradiation plan in order to apply a particle beam in accordance with the predetermined dose distribution in the target volume, the target volume comprising a plurality of isoenergy layers,

wherein a boundary condition is prescribed for at least one of the isoenergy layers,

wherein the irradiation plan is determined such that the boundary condition for the at least one isoenergy layer is observed,

wherein the boundary condition comprises at least one of the following conditions:

a minimum peak energy,

a maximum peak energy,

a minimum number of raster points,

a minimum overall number of particles,

a minimum overall dose,

a minimum dose contribution to an overall dose to be applied,

a minimum contribution to a target function calculated for determining the irradiation plan, and

a minimum dose compensation error, wherein the dose compensation error specifies an error that occurs as a result of the non-irradiation of the respective isoenergy layer despite corresponding compensation by the irradiated isoenergy layers, and

wherein at least one individual boundary condition is prescribed for each isoenergy layer of the plurality of isoenergy layers.

11. The method as claimed in claim 3 , wherein an individual boundary condition is prescribed for each isoenergy layer.

12. The method as claimed in claim 3 , wherein a same condition is prescribed for each isoenergy layer in respect of at least one of the conditions.

13. The method as claimed in claim 3 , wherein at least one planning result of a group of planning results for the irradiation plan and for the further irradiation plan is determined for evaluating the irradiation plan,

wherein the group of planning results comprises:

a dose/volume histogram,

a specification of how much of the dose is applied in the target volume according to the irradiation plan, and

a specification of how much of the dose is applied in at least one organ at risk of the examination object according to the irradiation plan.

14. The method as claimed in claim 13 , wherein the target function, which is calculated for determining the irradiation plan, comprises a penalty term, and

wherein the penalty term reduces a quality of a function value to be optimized of the target function further as a distance in accordance with the irradiation plan to the respective condition decreases.

15. The method as claimed in claim 13 , wherein a preliminary irradiation plan is determined in order to apply the particle beam in the target volume in accordance with the predetermined dose distribution, and

wherein the boundary condition is prescribed depending on the preliminary irradiation plan.

16. The method as claimed in claim 3 , wherein the target function, which is calculated for determining the irradiation plan, comprises a penalty term, and

wherein the penalty term reduces a quality of a function value to be optimized of the target function further as a distance in accordance with the irradiation plan to the respective condition decreases.

17. The method as claimed in claim 3 , wherein a preliminary irradiation plan is determined in order to apply the particle beam in the target volume in accordance with the predetermined dose distribution, and

wherein the boundary condition is prescribed depending on the preliminary irradiation plan.

18. A method for determining an irradiation plan for a particle irradiation unit, wherein the particle irradiation unit is used to irradiate a target volume within an examination object with a particle beam depending on the irradiation plan, the method comprising:

prescribing the target volume and a predetermined dose distribution;

determining the irradiation plan in order to apply the particle beam in accordance with the predetermined dose distribution in the target volume, the target volume comprising a plurality of isoenergy layers, wherein a boundary condition is prescribed for at least one isoenergy layer of the plurality of isoenergy layers; and

determining a further irradiation plan, wherein, for the determining of the further irradiation plan, the boundary condition is lifted for at least one specific one isoenergy layer of the plurality of isoenergy layers, in which no particles are applied in accordance with the irradiation plan since the boundary condition is broken, such that the further irradiation plan is determined without there being a restriction by the boundary condition with respect to the at least one specific isoenergy layer, and wherein a plan quality of the irradiation plan depending on the dose distribution is compared to a further plan quality of the further irradiation plan depending on the dose distribution for evaluating the irradiation plan,

wherein the irradiation plan is determined such that the boundary condition for the at least one isoenergy layer is observed, and

wherein the boundary condition comprises at least one of the following conditions:

a minimum peak energy,

a maximum peak energy,

a minimum number of raster points,

a minimum overall number of particles,

a minimum overall dose,

a minimum dose contribution to an overall dose to be applied,

a minimum contribution to a target function calculated for determining the irradiation plan, and

a minimum dose compensation error, wherein the dose compensation error specifies an error that occurs as a result of the non-irradiation of the respective isoenergy layer despite corresponding compensation by the irradiated isoenergy layers.