Using Ionising Radiation Flashcards
When are radioactive sources safe?
When the radiation emitted is at the same level as background radiation. Half life indicates how long this will take.
Describe how radiation treats cancer.
Gamma ways at certain doses can kill cells. They can be directed in the right direction to kill cancerous cells without killing too many normal cells. However, some will be hit, causing the person receiving the treatment to feel ill.
Describe how sterilising medical equipment is used..
A gamma source can be used to sterilise equipment by killing microbes. Boiling plastic equipment would damage them. This method is ideal. Highly radioactive sources with long half lives need to be used so they are not replaced often.
Describe the process of using radiation to sterilise food…
Radiation kills microbes, preserving the food and making it last longer. The radiation does not last and the food is not radioactive so it’s safe to consume after.
Describe how tracers are used…
These are radioactive molecules that are injected with external detectors to monitor the molecules. They detect cancer or detect whether an organ works properly. The molecules must be beta or gamma so they can pass out of the body. They must have a short half life so radiation leaves fast.
What are sources of background radiation?
From natural radioactive elements in the air, soil, living things, and in rock beneath us.
From space - radiation from the sun. (Cosmic rays)
From human activity - nuclear explosions and waste from power plants.
Background radiation is…
Radiation all around us.
If the beam is focused in radiotherapy, this prevents cells from being ….
However, some cells are inevitably …. Causing people to feel ill.
Irradiated, killed.
Why can’t alpha radiation be used as an emitter for tracers?
This radiation is highly ionising and the least penetrating.
6 marker - some countries allow soft fruit to be sterilised by radiation so that it has a longer shell life in shops. How is this sterilised without harming people?
The food is sterilised with gamma radiation. This is ionising and so breaks up molecules in the microbes into ions, causing the microbes to die. The radiation is exposed for a long time in order to kill all microbes. The food is close to the source. During this time, workers can protect themselves by standing behind a concrete or lead block, so they are protected from irradiation. By killing the microbes, this gives the fruit a longer shell life so the fruit must be sealed in a air-tight container to ensure that it is preserved correctly. The workers should be checked often to ensure the radiation levels are not too high, with rubber gloves and lead aprons to protect them from the radiation. Workers should not go near the source.
Why can’t alpha radiation be used as an emitter for tracers?
This radiation is highly ionising and the least penetrating.
6 marker - some countries allow soft fruit to be sterilised by radiation so that it has a longer shell life in shops. How is this sterilised without harming people?
The food is sterilised with gamma radiation. This is ionising and so breaks up molecules in the microbes into ions, causing the microbes to die. The radiation is exposed for a long time in order to kill all microbes. The food is close to the source. During this time, workers can protect themselves by standing behind a concrete or lead block, so they are protected from irradiation. By killing the microbes, this gives the fruit a longer shell life so the fruit must be sealed in a air-tight container to ensure that it is preserved correctly. The workers should be checked often to ensure the radiation levels are not too high, with rubber gloves and lead aprons to protect them from the radiation. Workers should not go near the source.
