1.What is ultrasound endoscopy? Ultrasound endoscopy is an ultrasound endoscope (EUS for short) is an advanced medical device that integrates ultrasound and endoscopy. It places a miniature high-frequency ultrasound probe at the front of the endoscope, and when the endoscope enters the gastric cavity, while the endoscope directly observes the morphology of the cavity, it can also perform real-time ultrasound scanning to obtain ultrasound images of the histological features of the canal wall at all levels and the surrounding adjacent organs. 2. What are the advantages of ultrasound endoscopy? The main advantages of EUS are to determine the nature of submucosal lesions in the stomach and intestines, to determine the depth and extent of invasion of malignant tumors in the digestive tract, and to diagnose diseases of the pancreatic system. Unlike a regular gastroscope, an ultrasound endoscope has an additional ultrasound probe at the front end. This small probe is sent into the gastric cavity with the gastroscope for ultrasound detection, allowing deep lesions in the esophagus and stomach to be seen. Therefore, ultrasound endoscopy has excellent diagnostic and therapeutic value for augmented lesions of the esophagus and stomach. In addition, ultrasound endoscopy has other uses, such as ultrasound endoscopy can help doctors determine the depth of gastric cancer invasion and surrounding lymph node metastasis, and can identify whether gastric ulcers are benign or malignant. The traditional methods of pancreatic examination are: body ultrasound, CT, MRI and retrograde pancreatic ductography (ERCP). The application of pancreatic EUS must be contrasted with traditional pancreatic examination methods to complement each other in order to arrive at the most optimal diagnosis. EUS is now recognized as the most sensitive method for detecting microscopic pancreatic lesions, which can be detected in as little as 2-3 mm. Fine needle aspiration cytology under EUS guidance can provide a qualitative diagnosis of early microscopic lesions in the pancreas. The application of EUS can perform TNM staging of pancreatic cancer and determine the possibility of surgical resection. For pancreatic cysts, EUS not only has diagnostic value, but also can be used for interventional treatment