Inclusion Criteria:  Aged 20-65 health volunteers without any contraindication  Exclusion Criteria:  Person allergy to polyethylene glycol. Phenylkentouria Congestive heart failure (NYHA grade 3) Renal function impairment. Difficulty in swallowing, GI perforation, GI bleeding, toxic enterocolitis, toxic colitis, megacolon, diverticulitis, peritonitis Body weight less than 20kg Wrist more than 120cm Gastrointestinal tract obstruction Pregnant woman. Person with electrical medical implantation such as pacemaker, cochlear implant or other medical devices. Person implanted with metal medical device such as metal implantation, metallic stent, metallic denture, metallic valve, metallic joint, metallic joint or plate. Person with history of abdominal surgery. Person with cancer. Person with bleeding tendency Person with asthma History of cardiac infraction, pulmonary embolism, stroke in recent 6 months Heart failure with NYHA grades 4