Treatment planning using modulability and visibility factors

1. A method for use in a treatment planning process, comprising:

determining a modulability factor, wherein the modulability factor is a measure of a collimator's ability to modulate its leaves to achieve a given shape for a target;

determining a treatment parameter by a processor using the modulability factor; and

storing the treatment parameter in a medium.

2. The method of claim 1 , wherein the modulability factor is determined by considering a movement of sub-volume projections in an aperture.

3. The method of claim 1 , wherein the modulability factor is a function of a number of leaves participating to form a shape of a fluence.

4. The method of claim 1 , wherein the modulability factor is a function of a geometry of the target and a geometry of a critical organ.

5. The method of claim 1 , further comprising determining a visibility factor, wherein the treatment parameter is determined using also the visibility factor.

6. The method of claim 5 , wherein the visibility factor is a measure of how well a ray associated with a collimator configuration reaches the target without traversing a critical organ.

7. The method of claim 5 , wherein the visibility factor is a function of a geometry of the target and a geometry of a critical organ.

8. The method of claim 1 , wherein the act of determining the treatment parameter comprises determining an objective function that is a function of the modulability factor and a visibility factor.

9. The method of claim 8 , wherein the act of determining the treatment parameter further comprises performing an optimization using the objective function.

10. The method of claim 1 , wherein the treatment parameter represents one or more of an isocenter position, a rotation axis, a collimator position, a patient support position, a target fluence, a dose, a dose rate, a gantry position, a gantry speed, a leaf sequence, a beam energy, a beam-on condition, and a beam-off condition.

11. The method of claim 10 , wherein the act of determining the modubility factor is performed using the processor.

12. The method of claim 1 , wherein the medium comprises a non-transitory medium.

13. A method for use in a treatment planning process, comprising:

determining a modulability factor;

determining a treatment parameter using the modulability factor; and

storing the treatment parameter in a medium;

wherein the act of determining the modulability factor comprises determining a longest target segment for a leaf of a collimator.

14. The method of claim 13 , wherein the act of determining the modulability factor further comprises determining a number of leaves participating to form a shape of a fluence.

15. The method of claim 14 , wherein the longest segment for the leaf is used to determine a first factor M 1 , and the number of leaves participating to form the shape of the fluence is used to determine a second factor M 2 , and wherein the modulability factor is determined using M 1 and M 2 .

16. A method for use in a treatment planning process, comprising:

determining a modulability factor;

determining a treatment parameter using the modulability factor;

storing the treatment parameter in a medium; and

determining a visibility factor, wherein the treatment parameter is determined using also the visibility factor;

wherein the visibility factor is determined by:

determining an amount of target regions traversed by a ray;

determining an amount of critical regions traversed by the ray; and

determining a difference using the determined amount of the target regions and the determined amount of the critical regions.

17. A system for use in a treatment planning process, comprising a processor, wherein the processor is configured for:

determining a modulability factor, wherein the modulability factor is a measure of a collimator's ability to modulate its leaves to achieve a given shape for a target; and

determining a treatment parameter using the modulability factor.

18. The system of claim 17 , wherein the modulability factor is determined by considering a movement of sub-volume projections in an aperture.

19. The system of claim 17 , wherein the modulability factor is a function of a number of leaves participating to form a shape of a fluence.

20. The system of claim 17 , wherein the modulability factor is a function of a geometry of the target and a geometry of a critical organ.

21. The system of claim 17 , wherein the processor is further configured for determining a visibility factor, and wherein the processor is configured to determine the treatment parameter using also the visibility factor.

22. The system of claim 21 , wherein the visibility factor is a measure of how well a ray associated with a collimator configuration reaches the target without traversing a critical organ.

23. The system of claim 21 , wherein the visibility factor is a function of a geometry of the target and a geometry of a critical organ.

24. The system of claim 21 , wherein the processor is configured to determine the visibility factor by:

determining an amount of target regions traversed by a ray;

determining an amount of critical regions traversed by the ray; and

determining a difference using the determined amount of the target regions and the determined amount of the critical regions.

25. The system of claim 17 , wherein the processor is configured for determining the treatment parameter by determining an objective function that is a function of the modulability factor and a visibility factor.

26. The system of claim 25 , wherein the processor is configured for determining the treatment parameter by performing an optimization using the objective function.

27. The system of claim 17 , wherein the treatment parameter represents one or more of an isocenter position, a rotation axis, a collimator position, a patient support position, a target fluence, a dose, a dose rate, a gantry position, a gantry speed, a leaf sequence, a beam energy, a beam-on condition, and a beam-off condition.

28. A system for use in a treatment planning process, comprising a processor, wherein the processor is configured for:

determining a modulability factor; and

determining a treatment parameter using the modulability factor;

wherein the processor is configured for determining the modulability factor by determining a longest segment for a leaf of a collimator.

29. The system of claim 28 , wherein the processor is configured for determining the modulability factor by determining a number of leaves participating to form a shape of a fluence.

30. The system of claim 29 , wherein the processor is configured to use longest segment for the leaf to determine a first factor M 1 , and use the number of leaves participating to form the shape of the fluence to determine a second factor M 2 , and wherein the processor is configured for determining the modulability factor using M 1 and M 2 .

31. A method for use in a treatment planning process, comprising:

determining a visibility factor, wherein the visibility factor is a measure of how well a ray associated with a collimator configuration reaches a target without traversing a critical organ;

determining a treatment parameter by a processor using the visibility factor; and

storing the treatment parameter in a medium.

32. The method of claim 31 , wherein the visibility factor is a function of a geometry of the target and a geometry of the critical organ.

33. The method of claim 31 , wherein the act of determining the visibility factor and the act of determining the treatment parameter are performed using a processor.

34. The method of claim 31 , wherein the medium comprises a non-transitory medium.

35. A method for use in a treatment planning process, comprising:

determining a visibility factor;

determining a treatment parameter using the visibility factor; and

storing the treatment parameter in a medium;

wherein the visibility factor is determined by:

determining an amount of target regions traversed by a ray;

determining an amount of critical regions traversed by the ray; and

determining a difference using the determined amount of the target regions and the determined amount of the critical regions.

36. A system for use in a treatment planning process, comprising a processor, wherein the processor is configured for:

determining a visibility factor, wherein the visibility factor is a measure of how well a ray associated with a collimator configuration reaches a target without traversing a critical organ; and

determining a treatment parameter using the visibility factor.

37. The system of claim 36 , wherein the visibility factor is a function of a geometry of the target and a geometry of the critical organ.

38. A system for use in a treatment planning process, comprising a processor, wherein the processor is configured for:

determining a visibility factor; and

determining a treatment parameter using the visibility factor;

wherein the processor is configured for determining the visibility factor by:

determining an amount of target regions traversed by a ray;

determining an amount of critical regions traversed by the ray; and

determining a difference using the determined amount of the target regions and the determined amount of the critical regions.