Methods and apparatus for the planning and delivery of radiation treatments

A system for delivery of radiation dose to a target area within a subject, the system comprising:

• a treatment radiation source for outputting a treatment radiation beam;
• a support for supporting the subject;
• a movement mechanism for moving the treatment radiation source relative to the subject along a trajectory;
• one or more sensors for monitoring a respiratory cycle of the subject;
• a controller configured, in accordance with a radiation delivery plan, to:
• cause the treatment radiation source to deliver the treatment radiation beam to the subject while causing the movement mechanism to effect relative movement between the treatment radiation source and the subject along the trajectory;
• while causing the movement mechanism to effect relative movement between the treatment radiation source and the subject along the trajectory, cause the treatment radiation source to vary at least one of an intensity of the treatment radiation beam by varying a radiation output rate of the treatment radiation source according to the radiation delivery plan over at least a portion of the trajectory and a shape of the radiation treatment beam over at least a portion of the trajectory;
• deactivate delivery of the treatment radiation beam upon determining that the respiratory cycle of the subject has moved a location of the target area outside of an acceptable range;
• and
• reactivate delivery of the treatment radiation beam upon determining that the respiratory cycle of the subject has moved the location of the target area to within the acceptable range;
• to thereby deliver dose to the subject according to the radiation delivery plan.