The present disclosure relates to a method for controlling a radiation therapy by a radiation therapy apparatus (200) of a target volume (246) in a subject (244) in accordance with an irradiation plan (199). The method comprises: generating a motion model of a movement of the subject (244), the motion model comprising patterns (326A-E) of values of at least one motion parameter (323)； determining, during a predefined irradiation time window, current values of the motion parameter (323)； determining if the distribution of the current values correspond to a given pattern of the patterns (326A-E) of the model； in response to determining that the distribution of the current values correspond to the given pattern and in case the given pattern is different from the pattern of the irradiation plan (199), modifying the irradiation plan in accordance with the given pattern, the modified irradiation plan becoming the irradiation plan.
