System and method for ion based radiotherapy treatment plan evaluation

1. A method of displaying results of an evaluation of a radiotherapy treatment plan for ion based radiotherapy on a computer system, the method comprising the steps, for at least a portion in a treatment volume, of:

obtaining from data memory information related to incident energy of ions that will stop in the portion;

calculating quantity values representative of the incident energy of the ions that will stop in the portion;

storing the calculated quantity values in the data memory; and

using the quantity values calculated for the portion as a measure of the robustness of the radiotherapy treatment plan the using step comprising:

assigning each of the calculated quantity values in the data memory to one of a number of energy layers; and

displaying for the portion of the treatment volume, a representation of the treatment volume and a visualization representing the energy layers in the representation of the treatment volume to which the calculated quantity values are assigned.

2. The method according to claim 1 , wherein the steps are performed for a plurality of portions in the treatment volume and the step of using the calculated quantity values comprises determining a distribution of the quantity values.

3. The method according to claim 1 , wherein the step of assigning each of the calculated quantity values includes assigning each of the calculated quantity values to one of a number of discrete or continuous labelled virtual energy layers.

4. The method according to claim 1 , wherein the information related to incident energy comprises at least one of the following:

energy layer control point index;

nominal control point energy; or

actual sampled energy per sampled ion.

5. The method according to claim 1 , wherein the information related to the incident energy of ions that will stop in the portion of the treatment volume includes a value indicating the combined quantity values of all ions that will stop in the portion of the treatment volume.

6. The method according to claim 1 , wherein the quantity value representative of the incident energy of the ions includes an average of the quantity values of the ions that will stop in the portion of the treatment volume.

7. The method according to claim 6 , wherein the average of the quantity values is either an average control point index or an average nominal energy of the ion in the portion of the treatment volume where it stops.

8. The method according to claim 1 , wherein the quantity values representative of the incident energy of the ions includes a value representing the difference between the quantity values of individual ions that will stop in the portion of the treatment volume.

9. The method according to claim 1 , wherein each energy layer is assigned a colour and the step of displaying includes displaying the portion of the treatment volume in the colour representing the energy layer to which the portion of the treatment volume is assigned.

10. The method according to claim 1 , wherein each energy layer is assigned an elevation level and the representation of the treatment volume in the step of displaying is a 3-dimensional representation of the treatment volume, where the portion of the treatment volume is displayed at the elevation level representing the energy layer to which the portion of the treatment volume is assigned.

11. A non-transitory computer readable medium encoded with computer executable instructions which, when run in a first computer device will cause the device to perform the method according to claim 1 .

12. A computer system comprising a processor, a data memory, and a program memory, wherein the program memory comprises the non-transitory computer readable medium encoded with computer executable instructions according to claim 11 .