A system or method for radiation treatment optimized for non-coplanar delivery, which includes a first collimator affixed to a gantry and a second collimator movably attached to the gantry to provide the second collimator a translation movement out of a gantry rotation plane. The system or method also includes a third collimator configured to collimate the beam in a direction of a target in the patient's body. The beam collimated by the third collimator is configured to follow the target during treatment. A method of performing rotation setup correction by rotating the treatment beam, without rotating the patient.
