The first (CB)CT scan is of the patient wearing the radiographic guide and the radiographic index.
For medical CT scanners, the patient should be positioned in such a way that the occlusal plane coincides with the axial slices. This can be checked using the laser pointers of the scanner as well as on the scout view. This is important to reduce the number of slices affected by artifacts due to metal restorations or amalgam dental fillings. No gantry tilt is allowed.
It is the responsibility of the clinician or radiology department to generate images of optimal quality in accordance with standard practices.