A Method of Radio-location for Use during Gastro-Intestinal Intubation

Abstract

Existing methods of locating, in a patient, the end of such appliances as the Ryle's tube are unsatisfactory because of insufficient sensitivity or undesirable X-ray exposure. A new method is described which uses a small coil in the tip of a Ryle's tube; wires along the tube connect the coil to a low-power 2 kc/s electrical oscillator. An external search-coil picks up the radiated signal and its intensity is presented as loudness of sound in a loudspeaker. Using such equipment, the position and axial direction of the oscillator coil can be determined with an accuracy and range fully adequate for clinical requirements.