Patent Number: 
Section: claims

1. A method for planning delivery of radiation dose to a target area within a subject, the method comprising:defining a set of one or more optimization goals, the set of one or more optimization goals comprising a desired dose distribution in the subject;specifying an initial plurality of control points along an initial trajectory, the initial trajectory involving relative movement between a radiation source and the subject in a source trajectory direction; anditeratively optimizing a simulated dose distribution relative to the set of one or more optimization goals to determine one or more radiation delivery parameters associated with each of the initial plurality of control points;wherein, for each of the initial plurality of control points, the one or more radiation delivery parameters comprise positions of a plurality of leaves of a multi-leaf collimator (MLC), the plurality of leaves moveable in a leaf-translation direction; andwherein during relative movement between the radiation source and the subject along the initial trajectory, the leaf-translation direction is oriented at a MLC orientation angle φ with respect to the source trajectory direction and wherein an absolute value of the MLC orientation angle φ satisfies 0°<|φ|<90°. 2. A planning method according to claim 1 wherein the absolute value of the MLC orientation angle φ satisfies 15°<=|φ|<=75°. 3. A planning method according to claim 1 wherein the absolute value of the MLC orientation angle φ satisfies 30°<=|φ|<=60°. 4. A planning method according to claim 1 wherein the MLC orientation angle φ is constant throughout the initial trajectory. 5. A planning method according to claim 3 wherein the MLC orientation angle φ is constant throughout the initial trajectory. 6. A planning method according to claim 3 wherein the initial trajectory comprises at least one pair of locations wherein a first beam directed from the radiation source toward the subject from a first one of the pair of locations and a second beam directed from the radiation source toward the subject from a second one of the pair of locations are substantially parallel but opposing one another. 7. A planning method according to claim 3 wherein the initial trajectory comprises a plurality of arcs, each arc involving relative movement between the radiation source and the subject within a corresponding plane. 8. A planning method according to claim 7 wherein, between successive ones of the plurality of arcs, the initial trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc intersect one another. 9. A planning method according to claim 7 wherein, between successive ones of the plurality of arcs, the initial trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc are parallel with one another. 10. A planning method according to claim 3 comprising, upon reaching one or more initial termination conditions:adding one or more additional control points to obtain an increased plurality of control points;iteratively optimizing the simulated dose distribution relative to the set of optimization goals to determine one or more radiation delivery parameters associated with each of the increased plurality of control points. 11. A planning method according to claim 1 wherein the initial trajectory comprises a plurality of arcs, each arc involving relative movement between the radiation source and the subject within a corresponding plane. 12. A planning method according to claim 11 wherein, between successive ones of the plurality of arcs, the initial trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc intersect one another. 13. A planning method according to claim 11 wherein, between successive ones of the plurality of arcs, the initial trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc are parallel with one another. 14. A planning method according to claim 1 comprising, upon reaching one or more initial termination conditions:adding one or more additional control points to obtain an increased plurality of control points;iteratively optimizing the simulated dose distribution relative to the set of optimization goals to determine one or more radiation delivery parameters associated with each of the increased plurality of control points. 15. A planning method according to claim 1 wherein the initial trajectory comprises a first non-self overlapping trajectory which involves non-self overlapping relative movement between the radiation source and the subject, wherein the initial plurality of control points comprises a first plurality of control points along the first non-self overlapping trajectory and wherein iteratively optimizing the simulated dose distribution relative to the set of one or more optimization goals comprises iteratively optimizing the simulated dose distribution relative to the set of one or more optimization goals over the first plurality of control points along the first non-self overlapping trajectory to determine one or more radiation delivery parameters associated with each of the first plurality of control points along the first non-self overlapping trajectory. 16. A planning method according to claim 15 wherein the initial trajectory comprises a second non-self overlapping trajectory which involves non-self overlapping relative movement between the radiation source and the subject, wherein the initial plurality of control points comprises a second plurality of control points along the second non-self overlapping trajectory and wherein iteratively optimizing the simulated dose distribution relative to the set of one or more optimization goals comprises iteratively optimizing the simulated dose distribution relative to the set of one or more optimization goals over the second plurality of control points along the second non-self overlapping trajectory to determine one or more radiation delivery parameters associated with each of the second plurality of control points along the second non-self overlapping trajectory. 17. A planning method according to claim 16 wherein the first and second non-self overlapping trajectories overlap one another over at least a portion thereof. 18. A method for planning delivery of radiation dose to a target area within a subject, the method comprising:defining a set of one or more optimization goals, the set of one or more optimization goals comprising a desired dose distribution in the subject;specifying an initial plurality of control points along an initial trajectory, the initial trajectory involving relative movement between a radiation source and the subject in a source trajectory direction; anditeratively optimizing a simulated dose distribution relative to the set of one or more optimization goals to determine one or more radiation delivery parameters associated with each of the initial plurality of control points;wherein, for each of the initial plurality of control points, the one or more radiation delivery parameters comprise positions of a plurality of leaves of a multi-leaf collimator (MLC), the plurality of leaves moveable in a leaf-translation direction; andwherein during relative movement between the radiation source and the subject along the initial trajectory, the leaf-translation direction is oriented at a MLC orientation angle φ with respect to the source trajectory direction and wherein an absolute value of the MLC orientation angle φ satisfies 0°<|φ|<90°;wherein the initial trajectory comprises at least one pair of locations wherein a first beam directed from the radiation source toward the subject from a first one of the pair of locations and a second beam directed from the radiation source toward the subject from a second one of the pair of locations are substantially parallel but opposing one another. 19. A method for delivering radiation dose to a target area within a subject, the method comprising:defining a trajectory for relative movement between a treatment radiation source and the subject in a source trajectory direction;determining a radiation delivery plan;while effecting relative movement between the treatment radiation source and the subject along the trajectory in the source trajectory direction, delivering a treatment radiation beam from the treatment radiation source to the subject according to the radiation delivery plan to impart a dose distribution on the subject;wherein delivering the treatment radiation beam from the treatment radiation source to the subject comprises varying an intensity of the treatment radiation beam over at least a portion of the trajectory. 20. A radiation delivery method according to claim 19 wherein the trajectory comprises a plurality of arcs, each arc involving relative movement between the radiation source and the subject within a corresponding plane. 21. A radiation delivery method according to claim 20 wherein, between successive ones of the plurality of arcs, the trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc intersect one another. 22. A radiation delivery method according to claim 20 wherein, between successive ones of the plurality of arcs, the trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc are parallel with one another. 23. A radiation delivery method according to claim 19 wherein varying the intensity of the treatment radiation beam over at least the portion of the trajectory comprises varying a rate of radiation output of the radiation source while effecting continuous relative movement between the treatment radiation source and the subject along the trajectory. 24. A radiation delivery method according to claim 23 wherein the trajectory comprises a plurality of arcs, each arc involving relative movement between the radiation source and the subject within a corresponding plane. 25. A radiation delivery method according to claim 24 wherein, between successive ones of the plurality of arcs, the trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc are parallel with one another. 26. A radiation delivery method according to claim 24 wherein, between successive ones of the plurality of arcs, the trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc intersect one another. 27. A radiation delivery method according to claim 19 wherein delivering the treatment radiation beam from the treatment radiation source to the subject comprises varying a shape of the treatment radiation beam over at least the portion of the trajectory. 28. A radiation delivery method according to claim 27 wherein varying the shape of the treatment radiation beam over at least the portion of the trajectory, comprises varying positions of a plurality of leaves of a multi-leaf collimator (MLC), the plurality of leaves moveable in a leaf-translation direction and wherein during relative movement between the treatment radiation source and the subject along the trajectory, the leaf-translation direction is oriented at a MLC orientation angle φ with respect to the source trajectory direction and wherein an absolute value of the MLC orientation angle φ satisfies 0°<|φ|<90°. 29. A radiation delivery method according to claim 28 wherein the absolute value of the MLC orientation angle φ satisfies 15°<=|φ|<=75°. 30. A radiation delivery method according to claim 28 wherein the absolute value of the MLC orientation angle φ satisfies 30°<=|φ|<=60°. 31. A radiation delivery method according to claim 30 wherein the MLC orientation angle φ is constant throughout the initial trajectory. 32. A radiation delivery method according to claim 30 wherein the trajectory comprises at least one pair of locations wherein a first treatment radiation beam directed from the radiation source toward the subject from a first one of the pair of locations and a second treatment radiation beam directed from the radiation source toward the subject from a second one of the pair of locations are substantially parallel but opposing one another. 33. A radiation delivery method according to claim 28 wherein the MLC orientation angle φ is constant throughout the initial trajectory. 34. A radiation delivery method according to claim 28 wherein the trajectory comprises a plurality of arcs, each arc involving relative movement between the radiation source and the subject within a corresponding plane. 35. A radiation delivery method according to claim 34 wherein, between successive ones of the plurality of arcs, the trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc intersect one another. 36. A radiation delivery method according to claim 34 wherein, between successive ones of the plurality of arcs, the trajectory comprises inter-arc relative movement between the radiation source and the subject, the inter-arc relative movement comprising movement such that the corresponding planes associated with each arc are parallel with one another. 37. A method for delivering radiation dose to a target area within a subject, the method comprising:defining a trajectory for relative movement between a treatment radiation source and the subject in a source trajectory direction;determining a radiation delivery plan;while effecting relative movement between the treatment radiation source and the subject along the trajectory in the source trajectory direction, delivering a treatment radiation beam from the treatment radiation source to the subject according to the radiation delivery plan to impart a dose distribution on the subject;wherein delivering the treatment radiation beam from the treatment radiation source to the subject comprises varying at least one of: an intensity of the treatment radiation beam; and a shape of the treatment radiation beam over at least a portion of the trajectory;wherein varying at least one of the intensity of the treatment radiation beam and the shape of the treatment radiation beam over at least the portion of the trajectory, comprises varying positions of a plurality of leaves of a multi-leaf collimator (MLC), the plurality of leaves moveable in a leaf-translation direction and wherein during relative movement between the treatment radiation source and the subject along the trajectory, the leaf-translation direction is oriented at a MLC orientation angle φ with respect to the source trajectory direction and wherein an absolute value of the MLC orientation angle φ satisfies 0°<|φ|<90°; andwherein the trajectory comprises at least one pair of locations wherein a first treatment radiation beam directed from the radiation source toward the subject from a first one of the pair of locations and a second treatment radiation beam directed from the radiation source toward the subject from a second one of the pair of locations are substantially parallel but opposing one another. 38. A method for delivering radiation dose to a target area within a subject, the method comprising:defining a trajectory for relative movement between a treatment radiation source and the subject in a source trajectory direction;determining a radiation delivery plan;while effecting relative movement between the treatment radiation source and the subject along the trajectory in the source trajectory direction, delivering a treatment radiation beam from the treatment radiation source to the subject according to the radiation delivery plan to impart a dose distribution on the subject;wherein delivering the treatment radiation beam from the treatment radiation source to the subject comprises varying at least one of: an intensity of the treatment radiation beam; and a shape of the treatment radiation beam over at least a portion of the trajectory;wherein varying at least one of the intensity of the treatment radiation beam and the shape of the treatment radiation beam over at least the portion of the trajectory comprises varying a rate of radiation output of the radiation source while effecting continuous relative movement between the treatment radiation source and the subject along the trajectory; andwherein the trajectory comprises at least one pair of locations wherein a first treatment radiation beam directed from the radiation source toward the subject from a first one of the pair of locations and a second treatment radiation beam directed from the radiation source toward the subject from a second one of the pair of locations are substantially parallel but opposing one another.