The investigators developed a wearable magnet tracking system, which provided a non-invasive and high accuracy method for capsule endoscopes localization. Data fusion from multiple sensors expanded positioning range and proposed localization algorithm overcame shortcomings of existing systems. This clinical trial was conducted to verify effectiveness and stability of the tracking system.

Inclusion Criteria:

• aged between 18 and 75
• agree to give written informed consent

Exclusion Criteria:

• dysphagia or symptoms of gastric outlet obstruction, suspected or known intestinal stenosis, overt gastrointestinal bleeding, history of upper gastrointestinal surgery or abdominal surgery altering gastrointestinal anatomy, or postabdominal radiation
• congestive heart failure, renal insufficiency, under therapeutic anticoagulation, in poor general condition (American Society of Anesthesiologists class III/IV), claustrophobia, metallic parts, a pacemaker or other implanted electromedical devices, or artificial heart valves
• pregnancy or suspected pregnancy
• exclusion criteria for standard magnetic resonance imaging examination such as the presence of surgical metallic devices, even though its low magnetic field technically would not interferewith such devices
• currently participating in another clinical study