Methods and apparatus for positioning a elongate hollow member at a desired location in a body in a medical procedure are provided. A position marker is removably disposed within a sheath. The sheath may be disposable. The sheath and enclosed position marker may be inserted into a lumen of a member to be positioned. The position in space of the position marker may be monitored by a position sensor to provide real-time information regarding a position of the member. The spatial relationship between the position marker and member may be fixed by securing the mounting member to the sheath and securing the sheath to the member.