P4d: Ultrasound

The concept of medical physics runs through this item. Ultrasound is an important medical diagnostic and therapeutic tool. This item looks at the properties of longitudinal waves, and investigates some of the medical uses of ultrasound.

  

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five features of a longitudinal wave.
Compression, Amplitude, Frequency, Wavelength and Rarefaction.
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What two purposes can ultrasound be used for - medical purposes.
To look inside people by scanning the body and to measure the speed of blood flow in the body.
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What is rarefaction?
A region of lower pressure where particles are spread out.
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What is amplitude?
The maximum distance the particles move from their normal position. The louder a sound is, the more energy it carries and the bigger its amplitude.
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What is compression?
A region of higher pressure where particles are squashed together.
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What is wavelength?
The distance between one high pressure region (compression) and the next.
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What is frequency?
The number of waves produced in one second, measured in hertz, Hz. A higher pitched sound has a higher frequency than a lower pitched sound.
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What is the frequency of ultrasounds higher than?and why?
Upper threshold of human hearing (20,000 hz) the ear cannot detect these high frequencies.
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Ultrasound can be used in medicine for what purposes?
Non-invasive therapeutic reasons - e.g to break down kidney stones.
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How are ultrasounds used in body scans?
Some of the ultrasound is reflected at each boundary between different tissues or organs. The depth of each layer is calculated using the time taken for each reflected wave to return.
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How are ultrasounds used in the breaking down of kidney stones?
A high powered ultrasound wave is used to break down kidney stones and other stones in the body. The stones vibrate until they shake themselves apart and are then easily passed out of the body via the urethra.
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What are the reasons for using ultrasound rather than X-rays for certain scans?
Able to produce images of soft tissue, and doesn't damage living cells.
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Other cards in this set

Card 2

Front

What two purposes can ultrasound be used for - medical purposes.

Back

To look inside people by scanning the body and to measure the speed of blood flow in the body.

Card 3

Front

What is rarefaction?

Back

Preview of the front of card 3

Card 4

Front

What is amplitude?

Back

Preview of the front of card 4

Card 5

Front

What is compression?

Back

Preview of the front of card 5
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