1.B ultrasound is painless, non-invasive and non-radioactive to the examinees, so there is no need to worry. When examining the heart, take off your shoes and lie flat on the examination bed after resting for a moment, unbutton your shirt and expose your chest for the doctor to examine; 3, when detecting deep organs susceptible to gas interference in the digestive tract, fasting or strict intestinal preparation is required. For example, the liver, bile and pancreas of the abdominal cavity should be fasted for 3 days before the detection of milk, soy products, sugar and other easily fermented gas-producing foods, and a light diet one day before the examination, and fasting and water fasting should be done on the same day; 4. organs, the bladder urine needs to be retained before the examination, you can drink about 1000 ml of boiled water 2 hours before the examination, and do not urinate 2-4 hours before the examination.