Ultrasound of the abdomen is capable of detecting certain tumors and is the preferred screening modality for tumor screening of some tissues and organs. Abdominal ultrasound can examine more items, covering almost all tissues and organs in the upper abdomen, lower abdomen, pelvic cavity and retroperitoneum. For example, the liver, gallbladder, pancreas, spleen and kidney in the upper abdomen, and the ureter, appendix and uterine adnexa in the lower abdomen and pelvis. Although cavernous organs such as the gastrointestinal tract are not the strong point of ultrasound examination, in some cases ultrasound can also detect tumors in the gastrointestinal tract when they are present. For organs with clearer display, such as the liver, tumors of two millimeters to several centimeters can be clearly displayed. However, for tumors of the gastrointestinal tract, due to serious gas interference or relatively small tumors, ultrasound can easily misdiagnose and miss them. Especially for some very early tumors, which generally do not have particularly typical manifestations, or some diffuse malignant tumors, these are easy to be missed by ultrasound. In addition, abdominal ultrasound can describe the size, shape, internal echogenicity, peripheral conditions, blood flow and other information of the detected tumor, thus helping to make a judgment on the nature of the tumor.