A system for registering an anatomical region (490, 1190, 1670) with a scanned image of the anatomical region, the system comprising: a mouldable appliance (310,510) configured for being moulded into a formed appliance (410,1180,1510,1660) having an appliance geometry shaped to mate with a surface geometry of at least a portion of the anatomical region, wherein the formed appliance resists deformation and when attached to the anatomical region, the formed appliance resists displacement relative to the anatomical region; a fiducial body (320,420,520,1520,1645), the fiducial body being attached to the mouldable appliance, the fiducial body having a shape defined by an external surface of the fiducial body such that an orientation of the fiducial body relative to the anatomical region is uniquely determinable from the shape, the fiducial body being scannable to provide a three-dimensional volume representation of the shape, and wherein the mouldable appliance and the fiducial body are configured such that when the mouldable appliance is moulded into the formed appliance, the fiducial body becomes rigidly fixed to the formed appliance such that the fiducial body is in a fixed spatial relationship with the formed appliance, wherein at least a part of the shape including a part of the external surface of the fiducial body is detectable to a scanner conducting a scan of the anatomical region to provide a three-dimensional volume representation of the at least a part of the shape including a part of the external surface of the fiducial body in a scanned image, the orientation of the fiducial body being determinable from a three-dimensional volume representation of the at least a part of the shape including a part of the external surface of the fiducial body that is scanned; a data processor and a memory module, the data processor being coupled to the memory module, the memory module being configured to store a reference model, the data processor being configured to determine a mapping transformation between the anatomical region and the scanned image that aligns a three-dimensional volume representation of the at least a part of the shape including a part of the external surface of the fiducial body with a corresponding part of the reference model, characterised in that the reference model is a reference model of the shape including the external surface of the fiducial body. a mouldable appliance (310,510) configured for being moulded into a formed appliance (410,1180,1510,1660) having an appliance geometry shaped to mate with a surface geometry of at least a portion of the anatomical region, wherein the formed appliance resists deformation and when attached to the anatomical region, the formed appliance resists displacement relative to the anatomical region; a fiducial body (320,420,520,1520,1645), the fiducial body being attached to the mouldable appliance, the fiducial body having a shape defined by an external surface of the fiducial body such that an orientation of the fiducial body relative to the anatomical region is uniquely determinable from the shape, the fiducial body being scannable to provide a three-dimensional volume representation of the shape, and wherein the mouldable appliance and the fiducial body are configured such that when the mouldable appliance is moulded into the formed appliance, the fiducial body becomes rigidly fixed to the formed appliance such that the fiducial body is in a fixed spatial relationship with the formed appliance, wherein at least a part of the shape including a part of the external surface of the fiducial body is detectable to a scanner conducting a scan of the anatomical region to provide a three-dimensional volume representation of the at least a part of the shape including a part of the external surface of the fiducial body in a scanned image, the orientation of the fiducial body being determinable from a three-dimensional volume representation of the at least a part of the shape including a part of the external surface of the fiducial body that is scanned; a data processor and a memory module, the data processor being coupled to the memory module, the memory module being configured to store a reference model, the data processor being configured to determine a mapping transformation between the anatomical region and the scanned image that aligns a three-dimensional volume representation of the at least a part of the shape including a part of the external surface of the fiducial body with a corresponding part of the reference model, characterised in that the reference model is a reference model of the shape including the external surface of the fiducial body.