Non-cryogenic system to locate and track a magnetically tagged capsule in the gastrointestinal tract

Magnetic measurements can be used to trace the movement and dissolution of an oral drug dosage form in the gastrointestinal tract. These studies have either used cryogenic magnetic sensors, a permanent magnet or ac excitation to detect the magnetic material. Our aim is to develop a three-dimensional magnetic tracking system that uses room temperature magnetic sensors and can detect a modest amount of magnetic material. Previously we demonstrated that a capsule tagged with 500 mg of iron oxide could be detected and tracked with such a tracking system. We have since improved the tracking system and can detect and track a target with as little as 50 mg of iron oxide. We plan to demonstrate this system on human subjects shortly.