There is disclosed an apparatus and method for locating a medical tube within the body of a patient. The medical tube is located by a detection apparatus which senses the static magnetic field strength gradient generated by a magnet associated with the medical tube and indicates the value of the gradient...http://www.google.ca/patents/US5622169?utm_source=gb-gplus-sharePatent US5622169 - Apparatus and method for locating a medical tube in the body of a patient
