Disclosed is a method for determining a positional pattern of an irradiation unit for irradiating a patient with treatment radiation. Optimal order data describing an order of the irradiation unit positions for which the statistical value is optimal is determined. The optimal order data is determined based on irradiation unit position data describing irradiation unit positions of the irradiation unit for which the imaging device has a free viewing direction onto the position of the patient, position orders data describing all possible orders of the irradiation unit positions for which the imaging device has a free viewing direction onto the position of the patient, and intersection angle data describing a statistical quantity of the intersection angles between free viewing directions of the imaging unit for irradiation unit positions which are immediately subsequent in the order described by the position orders data.
