Inclusion Criteria:  patients aged 18-75 years old who intend to undergo magnetron capsule gastroscopy, regardless of gender sign informed consent form  Exclusion Criteria:  dysphagia, known or suspected gastrointestinal obstruction、stricture and fistula patients with severe somatic diseases unable to complete examination known active upper gastrointestinal bleeding previous history of upper digestive tract or abdominal surgery to change gastrointestinal anatomy patients with cardiac pacemakers or implanted with other electronic medical instruments and magnetic metal foreign bodies pregnant women claustrophobia or other mental disorders uncontrollable