Patent ID: 8113210

Claim:
A medical device comprising: a medical tube configured for positioning in a body and defining a longitudinal axis; a passive integrated transponder on said tube, said transponder configured for generating an electromagnetic signal at a designated frequency in a frequency range of 120 kHz to 135 kHz; and a handheld reading device tuned to said designated frequency and including a grid dip oscillator and processing means configured for determining each end of said transponder by sensing magnetic poles of the electromagnetic signal generated by said transponder at said designated frequency when said reading device is physically moved over said transponder on said medical tube while said medical tube is in the body and determining a location of said transponder based on said locations of the magnetic poles sensed by said reading device, said reading device configured for providing at least one of a visual signal and an audio signal proportional to a magnitude of the electromagnetic signal sensed by said reading device for determining the locations of each end and a mid-portion of said transponder.