84. ULTRASOUNDS: THERMAL EFFECTS

Question 1

1. What happens to the temperature in tissues during Ultrasound exposure?

Answer 1

• the temperature rises

Question 2

2. Why does the temperature rise in the tissue?

Answer 2

• the tissue absorbs energy

Question 3

3. What 3 factors determine how a tissue can absorb energy?

Answer 3

1. The Organ composition
2. The Tissue composition
3. The Ultrasound Frequency

Question 4

4. Which physical parameter is the most influential when it comes to the absorption of energy?

Answer 4

• the Ultrasound frequency

THE HIGHER THE FREQUENCY:
- the faster the energy will be absorbed
- this will then heat the tissue up more

Question 5

5. What kind of temperatures can damage the tissue?

Answer 5

• a temperature rise of 2.5°C

NB:
- temperature elevations of up to 1°C cannot do harm
to the patient

Question 6

6. What can be said about the thermal effects of Diagnostic Ultrasounds?

Answer 6

• they are not likely to be hazardous for the patient

Question 7

7. How could we decrease the thermal effects?

Answer 7

• we could decrease the frequency
• we could limit the intensity
• we could limit the time of exposure