The present invention relates to a method for positioning a patient's body part including a target to be depicted by means of an imaging device relative to the imaging device, particularly an irradiation source of a radiation imaging device, that generates a radiation beam directed towards the target, the method being constituted to be executed by a processor of a computer and comprising the following steps: - receiving, at the processor, geometry data describing the geometry of at least one structure located in the field of view of the imaging device； - receiving, at the processor, tracking data describing the spatial location and/or orientation of the at least one structure within the field of view of the imaging device； - determining, with the processor, position data incorporating the geometry data and the tracking data, describing whether the location and/or orientation of the at least one structure with respect to an image trajectory, particularly a radiation beam trajectory through the target is desirable； - determining, with the processor, repositioning data describing a desired location and/or orientation of the at least one structure with respect to the image trajectory, particularly the radiation beam trajectory through the target； - outputting, from the processor, the repositioning data allowing for repositioning of the at least one structure. The present invention further relates to a corresponding computer program and system.
