uses and risks of radiation

Question 1

gamma sources

Answer 1

medical tracers

Question 2

how do medical tracers work?

Answer 2

radioactive isotopes are injected/swallowed and their progress around the body is followed using an external detector
a computer converts the reading into a display, showing where the strongest reading is coming from

Question 3

iodine-123

Answer 3

absorbed by the thyroid gland
gives out radiation
can be detected to indicate whether the thyroid gland is taking in iodine, as it should

Question 4

why are gamma emitters used in medical tracing?

Answer 4

-so radiation passes out of the body without causing too much ionisation
-short half-life so radioactivity quickly disappears

Question 5

radiotherapy

Answer 5

-gamma rays directed carefully at the right dosage to kill cancer cells
-some damage done to normal cells which makes patient feel ill
-beta emitters also used as radiation emitting implants

Question 6

when does tissue damage occur?

Answer 6

when radiation enters living cells and ionises atoms with them

Question 7

what can happen with too low doses?

Answer 7

-cause minor damage without killing cells
-give rise to mutant cells
-divide uncontrollably
-this is cancer

Question 8

what can happen with too high doses?

Answer 8

-kill cells completely
-cause radiation sickness
-if a lot of cells get blasted at once

Question 9

perceived risk

Answer 9

how risky a person thinks something is

Question 10

benefits of tracers that outweigh negatives

Answer 10

-used to diagnose life threatening conditions
-risk of cancer from one tracer very small

Question 11

benefits of radiotherapy that outweighs negatives

Answer 11

-can get rid of cancer entirely
-however prolonged exposure poses future risks and cause side effects