Determining the position of a device inside biological tissue

摘要: The position of a device such as an endotracheal tube 100 inside biological tissue is detected by probe 20 which generates small magnetic field disturbed magnetically permeable metal band 104 in the when narrow end positioned immediately adjacent to containing band. comprises central coil producing AC between two co-axial coils for sensing disturbances field. Signals from are amplified, integrated, and sent respective inputs comparator controls frequency oscillator. Thus emitted speaker 34 selection one series LED's 36 indicate proximity 104.