6.4.3.3 Uses of Nuclear Radiation

Question 1

What is nuclear radiation used in medicine for?

Answer 1

• exploration of internal organs
• control or destruction of unwanted tissue

Question 2

How are gamma sources used in medical tracers?

Answer 2

• radioactive isotopes injected into people (or swallowed)
• progress around body can be followed using tracer
• computer converts reading to a display to show where it is strongest

Question 3

What is an example of gamma sources in medical tracers?

Answer 3

• use of iodine-123
• absorbed by thyroid gland like normal iodine-127 but gives out radiation
• is used to indicate whether thyroid gland takes in iodine as it should

Question 4

Why are gamma sources used in medical tracers and not alpha?

Answer 4

• radiation passes out of body without causing much ionisation
• have a short half-life so radioactivity inside patient quickly disappears

Question 5

How can ionising radiation be used to treat cancers (radiotherapy)?

Answer 5

• high doses of them will kill all living cells
• gamma rays are directed carefully at just the right dosage so they don’t damage too many normal cells
• radiation-emitting implants (beta) can be put next to or inside tumours

Question 6

What are the risks to using radiation?

Answer 6

• tissue damage due to atoms being ionised
• can give rise to mutant cells as lower dosage causes minor damage
• higher doses kill cells completely, causing radiation sickness (leads to vomiting, tiredness, hair loss)

Question 7

What is perceived risk?

Answer 7

• how risky a person thinks something is
• not the same as the actual risk
• can vary from person to person

Question 8

How are tracers beneficial?

Answer 8

• can be used to diagnose life-threatening conditions
• risk of cancer from one use is very small

Question 9

Why is prolonged exposure to radiation a risk?

Answer 9

• can cause many side-effects
• radiotherapy still chosen as it may get rid of cancer entirely (benefits outweigh risks)