The efficacy of endoscopic ultrasonography using lubricating jelly for examining papilla of Vater

INTERVENTION: Conventional method Lubricating jelly using method CONDITION: tumor of the papilla of Vater PRIMARY OUTCOME: Sharpness for layers of the ampulla of Vater: conventional method vs lubricating jelly using method SECONDARY OUTCOME: 1. Sharpness for tumor margin and involvement, common bile duct ,and pancreatic duct; 2. Procedure time; 3. Administration of spasmolytic drugs; 4. Total dose of intravenous anesthetics; 5. Total dose of analgesics; 6. Complications; 7. Comparison between endosonographic imaging and pathological diagnosis INCLUSION CRITERIA: 1. Patients who are suspected of a tumor of the papilla of Vater and have indication for endosonography and give a written concent for this study. 2. Patients with pancreatobiliary disease who have indication for endosonography and give a written concent for this study.