Treatment

Question 1

What are the different types of radiation like for medical use?

Answer 1

• Alpha is absorbed by the skin so is of no use for diagnosis or therapy
• Beta can pass through the skin by not bone so its medical uses are limited but can be used to treat the eyes
• Gamma can penetrate through the body and is used in treatment. Cobalt-60 is a gamma emitting radioisotope that is used to treat cancer

Question 2

What is the big problem with radiotherapy?

Answer 2

Nuclear radiation passing through a material causes ionisation which damages living cells and increases the risk of cancer.

Question 3

How can materials be made radioactive?

Answer 3

When their nuclei absorb more neutrons in a nuclear reactor.

Question 4

What happens to tissue in the body when x-rays pass through it?

Answer 4

Absorbs some of the ionising radiation, amount absorbed depends on thickness and density of the material.

Question 5

How are x-rays made?

Answer 5

• Firing high-speed electrons at metal targets
• X-ray machine allows amount of x-rays to be controlled but you can’t control how much gamma radiation is emitted from a source

Question 6

What happens when a radioactive substance decays?

Answer 6

Emits an alpha or beta particle and loses any surplus energy by emitting gamma rays.

Question 7

How do tracers in the body work?

Answer 7

• Used to investigate inside the body without surgery
• Iodine-123 emits gamma radiation, used in thyroid gland
• Mixed with food or drink or injected into the body
• Monitored through the body

Question 8

What is used to destroy tumours in the body?

Answer 8

Radioisotope

Question 9

Why are three sources of radiation placed around a patient?

Answer 9

Each only gives 1/3 of the dose so that healthy tissue only receives 1/3 of the dose, limiting the damage. Or the sources rotate so that the tumour receives constant radiation but the healthy tissue receives only intermittent doses.