Lecture 17

Question 1

What is hyperthermia?

Answer 1

Cell death due to temperature rise.

Question 2

How are the effects of hyperthermia used medically?

Answer 2

It is used as an aid to radiotherapy or chemotherapy. It sensitises cells in tissue to give a more effective dose and increase the effectivity of fractionation.

Question 3

Where is local hyperthermia used?

Answer 3

• Skin/limbs: RF/ microwaves are used to raise the general core temperature of the tissue.
• Deeper tissues/ inter-luminal: ultrasound is more direct and effective for a specific region.

Question 4

How is local hyperthermia used?

Answer 4

Needles are directed to the tumours

Question 5

How is regional hyperthermia used?

Answer 5

Blood is heated or hyperthermia chambers are used for whole body hyperthermia.

Question 6

Define microwave ablation

Answer 6

Thermal energy delivered by microwaves to damage certain cells (e.g. to reduce underarm sweat).

Question 7

What is the equation for the SAR of ultrasound?

Answer 7

Q = heat energy
ρ = density
α = linear attenuation coefficient
I = intensity

Question 8

What is high-intensity focused ultrasound (HIFU) used for?

Answer 8

• Image-guided planning and beam steering
• Temperature mapping
• Treatment of fibroids
• Prostate cancer treatment