The invention concerns a method for obtaining operating parameters for an x-ray CBCT imaging apparatus in view of acquiring a set of data of a patient's maxillofacial region. The method comprises: —；identifying a patient's maxillofacial first region of interest (ROI1), —；determining a height of a horizontal plane of said patient's maxillofacial first region of interest (ROI1) when the patient is in an occlusion position or bites a patient positioning accessory, —；acquiring through a slit-shaped collimator window a first set of data relative to said patient's maxillofacial first region of interest (ROI1) including the horizontal plane using x-ray CBCT imaging, —；reconstructing an axial CBCT slice comprising the horizontal plane based on the first set of data relative to the reconstructed the patient's maxillofacial first region of interest (ROI1), —；displaying the reconstructed axial CBCT slice of the patient's maxillofacial first region of interest (ROI1) from the acquired first set of data, —；defining at least partially a second region of interest (ROI2) based on the displayed reconstructed axial CBCT slice of the patient's maxillofacial first region of interest (ROI1) and intersecting the latter, —；obtaining operating parameters for an x-ray CBCT imaging apparatus based on at least the defined second region of interest (ROI2) in view of acquiring a second set of data including the defined second region of interest (ROI2).
