Endoscopic ultrasound (EUS) is a medical procedure that combines endoscopy and ultrasound to obtain detailed, high-resolution images of internal organs. A tube with integrated ultrasound is inserted. Unlike a traditional ultrasound, which is performed from outside the body, EUS uses an endoscope with an ultrasound transducer at its tip to examine the inside of the gastrointestinal tract and surrounding areas. It is particularly useful for: diagnosing and staging tumors in the pancreas, esophagus, stomach, colon, and rectum; evaluating pancreatic diseases, such as chronic pancreatitis; detecting problems in the bile duct and gallbladder; characterizing lesions or masses in the intestinal walls; obtaining tissue samples (biopsies) in a guided and precise manner; and performing therapeutic interventions, such as cyst drainage or stent placement. It is performed under sedation.