1. A method for registering an anatomical region with a scanned image of the anatomical region, the method comprising: pressing a mouldable appliance against a surface of the anatomical region or a facsimile thereof to shape the mouldable appliance to conform to a surface geometry of the anatomical region to provide an intermediate appliance; hardening the intermediate appliance to retain an appliance geometry shaped to mate with the surface geometry of the anatomical region to provide the formed appliance wherein the formed appliance resists deformation; providing a fiducial body attached to the formed appliance such that the fiducial body is rigidly fixed to the formed appliance and is configured to be scannable to provide a three-dimensional volume representation of the fiducial body distinguishable from a three-dimensional volume representation of the anatomical region and the fiducial body being shaped and attached to the formed appliance such that the orientation of the fiducial body is uniquely determinable based at least in part on a degree of asymmetry of the fiducial body; attaching the formed appliance with the fiducial body attached thereto to the anatomical region such that when attached to the anatomical region the formed appliance resists displacement relative to the anatomical region; scanning the anatomical region with the formed appliance attached thereto and the fiducial body attached to the formed appliance to obtain a three-dimensional volume representation of at least a part of the fiducial body and an interior of the anatomical region in a scanned image; segmenting the part of the fiducial body in the three-dimensional volume representation of the at least a part of the fiducial body in the scanned image to obtain a segmented fiducial body region; aligning the segmented fiducial body region with a reference model of the fiducial body to obtain a mapping transformation; and operating a data processor to map locations in an interior of the anatomical region to corresponding locations in the three-dimensional volume representation of the interior of the anatomical region based on the mapping transformation.