An ultrasound scan is a very commonly held test, which uses high-frequency inaudible sound waves to create images of organs and structures inside your body. As it uses sound waves and not radiation, it is thought to be very safe. 

The scan is painless and takes about 15-45 minutes, depending on which parts of the body are being examined. A record of the results of the test can be made as still pictures or as a video recording.

It can help to determine the size, shape and consistency of internal organs such as liver, pancreas, gallbladder, thyroid gland, ovaries, testes, uterus and other; it helps to determine structures and abnormalities of joints, muscles, tendons. Ultrasound test is routinely held during pregnancy for monitoring the growth of unborn child. Doppler ultrasound scans are used to listen to the heartbeat of fetus and to visualize the blood flow in arteries or veins of extremities (upper or lower) for diagnosing if patient might have deep vein thrombosis, peripheral arterial disease, injury of blood vessels following trauma.

Duplex ultrasound combines traditional ultrasound with Doppler ultrasound.

If patient needs internal biopsy, a procedure in which a sample of tissue is taken, the biopsy needle can be guided to the right place by ultrasound scan.

In some situations, a clearer picture can be obtained from an ultrasound transducer that is within the body: swallowed into the esophagus, placed in the vagina or rectum.

Ultrasound scans are painless and safe. They have not been found to cause any problems or complications.