Some aspects include a system (100), apparatus (100), means and method (300, 500) for configuring a radiotherapy beam shaping device (80) to define a treatment field of view (410, 610,645), acquiring images of a patient area (405, 605) within the treatment field of view (410, 610, 645) based on an imaging radiation beam, determining a treatment motion model that predicts, based on the acquired images, a prediction treatment period during which the patient area will be within the treatment field of view (410, 610, 645) of the radiotherapy beam shaping device (80), and delivering a treatment radiation beam to the patient area (405, 605) for a time period equal to the prediction treatment period.
