How does ultrasound scanning work?
A small hand-held device generates very high-pitched sound waves above the range of the human ear. It is held to the skin and can be moved to view the body from different angles. A gel is often used to make good contact between the device and the skin. The sound waves enter the body and echo back when they meet the boundaries between different kinds of tissue. Structures near the surface send back echoes sooner than deep structures, and dense tissues send back stronger echoes. The same device receives the signal and sends it to a computer. Analysis of the data produces the image displayed on a monitor. What can you see with ultrasound scanning? Ultrasound is most commonly used to monitor the foetus during pregnancy. It enables doctors and radiographers to check growth rates and screen for abnormalities such as spina bifida and Downs syndrome. Ultrasound can also be used to watch blood flow through the heart and blood vessels. Images with this text: Ultrasound scan showing one of twin f
