Ultrasound

موضوع: Ultrasound الأحد فبراير 21, 2010 10:07 pm

Ultrasound

What does "Ultrasound" mean

Ultra = High or extreme

Ultrasound = sound waves above the frequency detectable by human ears

Physiology Ultrasound or ultrasonography

is a medical imaging technique that uses high frequency sound waves and their echoes. It is used to form an image of organs or tissue inside the body non-invasively. The technique is similar to the echolocation used by bats, whales and dolphins

Ultrasound is also used as a physiotherapy treatment where the sound waves are used to warm muscle tissue deep inside the body

How it works

The ultrasound machine transmits high-frequency (1 to 5 MHz) sound pulses into the body using a probe. The probe has special crystals that generate the sound waves and also detect sound waves reflected

When the sound waves hit a boundary between tissues (e.g. between fluid and soft tissue, soft tissue and bone) some of the sound waves are reflected back to the probe and the rest travel on further until they reach another boundary and are reflected back

The reflected waves are detected by the probe and relayed to the machine

The machine calculates the distance from the probe to the tissue or organ (boundaries) using the speed of sound in tissue (1,540 m/s) and the time of each echo's return (usually in the order of millionths of a second)

The machine displays the distances and intensities of the echoes on the screen and forms a two dimensional image