A guide wire assembly includes a guide wire, an optical fiber, and an insulating coating. The guide wire has a distal end, a proximal end, and a bore extending through the wire between the distal and proximal ends. The an optical fiber also includes a distal end and a proximal end and is located within the bore of the guide wire. The optical fiber extends at least between the distal and proximal ends of the guide wire. The insulating coating is around an outside diameter of the guide wire, and is applied such that the distal ends of the guide wire and optical fiber are exposed.