Ultrasound examination precautions: fasting】 When the examination site is “liver, bile, bile duct, pancreas, spleen, inferior vena cava, hepatic vein, abdominal aorta”, fasting is required 8 hours before the examination. Diabetic patients should hold off insulin injection or glucose-lowering medication on the day of fasting examination, and then inject or take it before meal after the examination. Ultrasound examination precautions: holding urine for examination] When the examination site is “bladder, uterine adnexa (transabdominal), prostate (transabdominal)”, you need to drink 1000 ml of water one hour before the examination, not to urinate, and to keep the bladder full enough for the examination. If you have both of the above mentioned parts that require fasting, please check the fasting items first, then eat and drink water! Do not drink water on an empty stomach, otherwise the waiting time for the bladder to fill up will be much longer than 1 hour. When it is necessary to observe the length of the cervical canal or the position of the lower edge of the placenta, it is also necessary to hold urine moderately (if you have a clear urge to urinate). Ultrasonography precautions: examination after urination】 Empty urine before examination. If there is an examination site that requires water to hold urine as described above, please check the urine holding item first. Ultrasound examination precautions] If the examination site is an “abdominal mass” or “pelvic mass”, fasting is required 8 hours prior to the examination of the upper abdominal mass. In the case of pelvic masses after gynecological tumor resection, patients should drink 1000 ml of water 1 hour before the examination and should not urinate.