GCSE Physics · Edexcel 1PH0 · Topic 6D
Uses and dangers of radiation
Key points
- Uses: tracers in medicine (short half-life gamma emitters), radiotherapy to kill cancer cells, sterilising equipment and food with gamma, smoke alarms (alpha), thickness gauges (beta).
- Irradiation is exposure to radiation from outside the body; it stops when you move away.
- Contamination is when radioactive atoms get onto or into something; it continues until removed or decayed. Alpha sources are most dangerous inside the body.
- Ionising radiation can damage or kill cells and cause mutations that may lead to cancer.
- Precautions: keep exposure time short, keep distance (use tongs), use shielding, store sources in lead-lined boxes, monitor dose with badges.
- Choose sources by type of radiation and half-life, e.g. a medical tracer needs a short half-life and must penetrate the body (gamma).
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Ionising radiation can kill cancer cells, sterilise equipment and find leaks, but it can also damage healthy cells. This sub-topic weighs those benefits against the risks and explains how people are protected.
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