Method and apparatus for acquiring volumetric CBCT radiographies in an apparatus having a rotary supporting arm, at whose ends at least an X-ray source and at least an X-ray sensor are positioned, said supporting arm having the aim of rotating said at least one source and at least one sensor around a patient； said method comprising the following steps: - Positioning a patient on the positioning device 7； - Acquiring a CBCT image through a trajectory having an angular extension lower than 360°； characterized in that the rotation centre of the trajectory (11) of said X-ray sensor (6) is never on the median sagittal plane (13) defined by the patient positioned inside the apparatus (1) and in that the trajectory is not symmetric to any of the possible sagittal planes of the patient.
