Many people in life are concerned that our ultrasound may emit radiation and have an impact on their own bodies. In fact, the working principle of ultrasound diagnostic equipment is similar to bat hunting, both emitting and receiving processed ultrasound waves to obtain useful information. In general, what is harmful to the human body refers to ionizing radiation, and ultrasound is essentially a high-frequency sound wave that cannot produce electromagnetic radiation, so it will not cause "radioactive" hazards. The ultrasound examination we use in clinical diagnosis usually has a frequency of 1-30MHz, so there is no need to worry at all under such conditions. Medical ultrasound diagnosis is widely used, which can both diagnose and use its principles to achieve the goal of treating certain diseases.
Does ultrasound require holding urine?
During bladder, ureter, prostate, and seminal vesicle examinations, unmarried women with high vaginal bleeding and pregnant women in the first 3 months of pregnancy need to hold their urine for ultrasound examination. The purpose of holding urine is to fill the bladder, reduce intestinal gas interference, and provide a good sound window for examination. When conducting gynecological examinations, it is generally required that the bladder urine volume be between 300-400ml, and the sign of good bladder filling is a supine position with slightly protruding lower abdomen. The probe should be able to press down and tolerate pressure.
Why can't we eat?
Ultrasound diagnosis has a high resolution for tissue structure, but on interfaces with high contrast such as solid gas or liquid gas, ultrasound is difficult to pass through and almost completely reflects. If some gases can be swallowed along with food after eating, causing an increase in intestinal gas. Some foods, such as legumes, are also prone to gas production, which limits the penetration of sound waves during abdominal ultrasound examination, resulting in unclear image display. Moreover, when the gastrointestinal tract is filled with food, the food will form the same sound image as lumps and stones, leading to misdiagnosis. Therefore, during the examination of abdominal organs, such as liver, gallbladder, pancreas, spleen, kidney, abdominal blood vessels, abdominal cavity, retroperitoneum, and intestinal tract, 6-8 hours of fasting is required. During this period, warm hot water can be drunk, and milk, Mantou, eggs, noodles, colored drinks, etc. are not allowed. This can reduce the interference of gastrointestinal chyme and gas, ensure the bile filling in the gallbladder, and improve the imaging quality. After eating, the contraction of the gallbladder becomes smaller, making it difficult to distinguish between physiological and pathological changes, and also affecting the display of lesions in the gallbladder, such as gallstones and polypoid lesions. In addition, for patients with frequent abdominal distension, it is recommended to have a light diet the night before the examination and take appropriate digestive promoting drugs before the examination.
What is the sticky substance applied to the body?
Before the examination, a medical ultrasound coupling agent was applied, which is a water-soluble liquid, colorless and transparent adhesive, non-toxic to the human body. After the examination, it can be wiped clean or washed with warm water. The purpose of applying coupling agent is to ensure good contact between the probe and the skin, which is beneficial for the transmission of ultrasound, improves imaging quality, and makes the image clearer.
Is this an ultrasound? Why is it black and white?
Although the ultrasound machine looks like a television, its "color" refers to color Doppler, which is a processing of blood flow in the body. Therefore, only when displaying blood vessels are they in color. The "red" and "blue" you see are the blood vessels in your body.
Without the use of Doppler function, the image remains black and white. So color ultrasound cannot be equated with color television.
Why did I finish checking so quickly while others watched for so long?
Generally speaking, the speed of ultrasound examination is related to the number of examination sites and the complexity of the examination results. Some examiners have a single site and do not have many abnormal findings, so the examination time will naturally be shorter, while some examiners have multiple sites and problems, and may even need repeated examinations and consultations before the final diagnosis can be made, and the time will inevitably be extended. If you feel that your examination time is relatively short, it may precisely indicate that your condition is not serious, so please do not blindly compare the examination time.