A position sensing system of nasogastric tube using a wireless magnetic ribbon type marker has been developed. A Qualityfactor of the marker is 121 which is 13 times higher than conventional LC resonated marker. Position accuracy within 6.4mm was obtained when the marker inside a commercial nasogastic tube was parallel translation to 100mm. The marker inside the tube was roughly tracked in esophagus and in trachea of human model.
