P2 - Uses Of Radiation Flashcards
How does alpha radiation work in smoke detectors?
It causes ionisation, and a current flows between the electrodes.
Smoke will absorb the radiation, the current stops, the alarm sounds.
How do tracers in medicine work?
They are injected or swallowed.
Their progress around the body is followed using an external detector.
A computer shows where the strongest reading comes from.
What is iodine-131 used for in traces?
It is absorbed by the thyroid gland and gives out radiation, which can be detected to show whether the thyroid gland is taking in iodine properly.
What isotopes must be taken into the body only and why?
Only gamma or short half-life beta so the radioactivity quickly disappears.
What type of rays should radiotherapy use?
Gamma rays.
Why are gamma rays used to treat cancers?
High doses will kill all living cells.
What are the pros and cons of using radiotherapy?
- damage is inevitably done to other cells, making the patient feel ill.
+ can successfully kill cancer.
What rays are used to sterilise food or surgical instruments?
Gamma rays.
What happens if you expose food to gamma rays?
It kills all microbes, keeping it fresh for longer.
What is the advantage of irradiation over boiling?
It doesn’t involve high temperatures so won’t damage food/surgical instruments.
What factors must isotopes used in sterilisation have?
Must be a strong emitter of gamma rays with a long half-life so it doesn’t need replacing often.
What do smoke detectors use?
Alpha radiation.
