Topic 40 Flashcards Preview

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Flashcards in Topic 40 Deck (10)
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1
Q

Describe Ultrasound

A

Frequency above 20000 Hz

Pulses sent and reflections recieved

Depedns on density differences

Shorter wavelength → Larger attenuation

2
Q

What is the Doppler effect?

A

Observed sound dependent if the source or observer are in motion and which direction they are moving

3
Q

Give the effects of ultrasound

A

Heat Effect

Cavitation

Emulgation and Dispersing effect

Chemical Effect

Biological effect

4
Q

What is the heat effect

A

Vibration energy is converted to heat

5
Q

What is cavitation?

A

Sudden creations of microscopic cavities briefly

May lead to boiling, ionisation and dissociation possible

6
Q

What is Emulgation and Dispersing effect?

A

Friction, heat effect and cavitation produces more stable and fine dispersion compared with other methods.

7
Q

What is the chemical effect of ultrasound.

A

Water ionised and excited

Producing OH, OH- and H+

8
Q

What is the biological effect of ultrasound?

A

Ultrasound can kill:

Bacteria, Viruses, Fungi, Small invertebrates and vertebrates

9
Q

Which types of ultrasound scan are there?

A

A-Scan (Show the emitted pulse and the reflected pulse)

B-Scan (Observes only the reflected pulse)

10
Q

What is Echoencephalography?

A

A-Scan

Located the midline between the two hemispheres

If the midline shows to be:

Symmetrical → Healthy

Asymmetrical → Tumour/Bleed