Topic 40

Question 1

Describe Ultrasound

Answer 1

Frequency above 20000 Hz

Pulses sent and reflections recieved

Depedns on density differences

Shorter wavelength → Larger attenuation

Question 2

What is the Doppler effect?

Answer 2

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

Question 3

Give the effects of ultrasound

Answer 3

Heat Effect

Cavitation

Emulgation and Dispersing effect

Chemical Effect

Biological effect

Question 4

What is the heat effect

Answer 4

Vibration energy is converted to heat

Question 5

What is cavitation?

Answer 5

Sudden creations of microscopic cavities briefly

May lead to boiling, ionisation and dissociation possible

Question 6

What is Emulgation and Dispersing effect?

Answer 6

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

Question 7

What is the chemical effect of ultrasound.

Answer 7

Water ionised and excited

Producing OH, OH^- and H⁺

Question 8

What is the biological effect of ultrasound?

Answer 8

Ultrasound can kill:

Bacteria, Viruses, Fungi, Small invertebrates and vertebrates

Question 9

Which types of ultrasound scan are there?

Answer 9

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

B-Scan (Observes only the reflected pulse)

Question 10

What is Echoencephalography?

Answer 10

A-Scan

Located the midline between the two hemispheres

If the midline shows to be:

Symmetrical → Healthy

Asymmetrical → Tumour/Bleed