Using Sound - Ultrasound Scanning
Ultrasounds and marine sonars share the same operating feature. They both work by detecting sound reflected from a body towards which sound is "shot" at. The ultrasound produces sound from a tiny vibrating crystal in the hand held scanner head. When the sound waves enter the tissues of different density, the reflected sounds arrive at the crystal head (which also helps detect the sound waves) at different times. This variance allows the ultrasound machine to generate the image of the object scanned.
Sound waves can be concentrated into a narrow beam that can be scanned from side to side. The returned echoes are compiled into an image by the computer and then visualized on a monitor.
Why Is Ultrasound Used?
Ultrasounds do not produce images of high quality. However, due to the nature of soundwaves, ultrasounds are best used for:
- examining fluid-filled organs - wombs, gallbladder, soft structures like the liver.
- revealing fetal abnormalities or the sex of a baby.
- heart imaging.
- checking the interior of the eye.
Doppler Ultrasound
The Doppler effect describes the compression (squashing) or rarefraction (spacing) of sound waves as the object producing or reflecting sound comes towards to goes away from the listener. Routinely used by surgeons to investigate the rate of blood flow, Doppler Ultrasound provides a means of looking at a system without getting inside it.
See also
X-rays
MRI scans
CAT scans
PET scans
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