# A hospital worker handles radioactive sources used in medical procedures. Explain why irradiation and radioactive contamination are considered differently when assessing the risk to the hospital worker.

> Pearson Edexcel International GCSE Physics (4PH1) — 7.2 Radioactivity · Explain · 4 marks

> A hospital worker handles two types of radioactive source: one is a sealed gamma-emitting source used to sterilise surgical equipment from outside its packaging, and the other is an unsealed liquid gamma-emitting tracer that is prepared and injected into patients.

## Mark scheme (4 marks)

1. Irradiation occurs when the worker is exposed to a radioactive source that is outside the body / object, so the worker does not become radioactive themselves.
2. Radioactive contamination occurs when radioactive atoms are introduced onto or into the worker, meaning the worker carries the source with them.
3. With contamination, the worker is continuously exposed to radiation from the decaying atoms for as long as the source remains on or in them, making it harder to limit exposure.
4. With irradiation, the worker can reduce risk by increasing distance from the source, reducing time of exposure, or using shielding, whereas these measures cannot remove contamination once it has occurred.

## Key terms

- [irradiation](https://www.gradenine.co.uk/glossary/irradiation)
- [radioactive contamination](https://www.gradenine.co.uk/glossary/radioactive-contamination)

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-hospital-worker-handles-radioactive-sources-7019259a) · Published by Druglandscape Ltd.