Ultrasound imaging is a common diagnostic medical procedure that uses high-frequency sound waves to produce dynamic images (sonograms) of organs, tissues, or blood flow inside the body. Prenatal ultrasound examinations are performed by trained professionals, such as sonographers, radiologists, and obstetricians. The procedure involves using a transducer, which sends a stream of high-frequency sound waves into the body and detects their echoes as they bounce off internal structures. The sound waves are then converted to electric impulses, which are processed to form an image displayed on a computer monitor. It is from these images that videos and portraits are made.
Obstetricians use ultrasound at a very low power level to check the size, location, number, and age of fetuses, the presence of some types of birth defects, fetal movement, breathing, and heartbeat. When ultrasound is used by a qualified clinician to check for this kind of medical information, the FDA says the medical benefit far outweighs any risk.
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At somewhat higher exposure levels, given daily for weeks at a time, ultrasound is used to speed the healing of bone fractures. At even higher levels, the technology produces a heating effect in tissue that is useful in treating sprains and pulled muscles.