Disclosed is a scanner for scanning fire tubes in heater treaters. A scanner may include a curved body. The curved body having an outside of a curve and an inside of a curve. At least one magnet is coupled to the outside of the curve of the curved body. At least one sensor is coupled adjacent the at least one magnet on the outside of the curve of the curved body. A data transmitter is coupled to the at least one sensor. At least one wheel is coupled to an edge of the curved body. A distance measurer is coupled to the curved body. A hook coupler is coupled to the curved body. A method of using the scanner for scanning a fire tube includes placing the scanner in the tube and pushing/pulling the scanner up and down the tube around the entire circumference of the tube.