1. A device for use in a system for displaying relative positions of two structures during a procedure on a body, the system including a scanning device for scanning the body to generate a scan image, said device comprising: a base having a top side and a bottom side operable to be attached to the body via the bottom side of said base; a fiducial marker operable to be removably attached to the top side of said base; and a sensor formed within and as one structure with said base, wherein the fiducial marker is spaced a predetermined distance from the body when the base is attached to the body, the predetermined distance being greater than a slice thickness used for obtaining the scan image creating a barrier that inhibits the fiducial marker from blending with the body in the scan image.