Abstract
The prototypes III and IV have a high image resolution power, for example, clearly visualizing the gastric wall in five layers, and with improvements of apical defection system, it becomes possible to introduce the scope (prototype IV) down into the descending portion of the duodenum. With satisfactory improvements, the prototype IV is clinically evaluated as a well accomplished ultrasonic upper G-I endoscope, and the scope will be surely contributory to the diagnosis of small mass lesions in the head of the pancreas and also for the estimation of the range and deepness of the gastric cancer invasion.
