Patent ID: 8416917

Claim:
A method comprising: determining a trajectory of a target volume; determining a treatment plan identifying a first portion of the trajectory of the target volume, a first angle of incidence, and a first irradiation field corresponding to the first portion of the trajectory, and identifying a second portion of the trajectory of the target volume and a second irradiation field corresponding to the second portion of the trajectory and to the first angle of incidence, the first portion of the trajectory commencing at a control point of the trajectory, and the second portion of the trajectory commencing at a second control point of the trajectory; positioning a treatment gantry to deliver a treatment beam to the target volume at the first angle of incidence; controlling a collimator to restrict the treatment beam to the first irradiation field; after controlling the collimator to restrict the treatment beam to the first irradiation field, monitoring the trajectory of the target volume until it is determined that the trajectory is at the first control point; in response to determining that the trajectory of the target volume is at the first control point, delivering the treatment beam to the first irradiation field at the first angle of incidence; controlling the collimator to restrict the treatment beam to the second irradiation field; after controlling the collimator to restrict the treatment beam to the second irradiation field, monitoring the trajectory of the target volume until it is determined that the trajectory is at the second control point; and in response to determining that the trajectory of the target volume is at the second control point, delivering the treatment beam to the second irradiation field at the first angle of incidence.