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.La présente invention concerne un procédé de positionnement d'une partie du corps d'un patient comprenant une cible à imager au moyen d'une source d'imagerie par rapport à un dispositif d'imagerie, notamment une source d'irradiation d'un dispositif d'imagerie par rayonnement qui génère un faisceau de rayonnement dirigé vers la cible, le procédé étant conçu pour être exécuté par un processeur d'un ordinateur et comportant les étapes suivantes: la réception, au niveau du processeur, de données de géométrie décrivant la géométrie d'au
