# Radioactive tracers are used in medicine to investigate how well organs are functioning. Explain why a radioactive tracer used inside the human body should emit gamma radiation rather than alpha radiation.

> Eduqas GCSE Physics — 9.3 Hazards and uses of radioactive emissions · Explain · 4 marks

## Mark scheme (4 marks)

1. Alpha radiation has a very short range / is absorbed quickly inside the body / cannot penetrate through body tissue to reach a detector outside
2. Gamma radiation can penetrate through body tissue / has a long range and can pass out of the body
3. So gamma radiation can be detected outside the body / allows an image or reading to be taken externally
4. Alpha radiation is more ionising than gamma / alpha causes more damage to body cells / gamma causes less ionisation so is less harmful to the patient

## Key terms

- [radioactive tracer](https://www.gradenine.co.uk/glossary/radioactive-tracer)
- [gamma radiation](https://www.gradenine.co.uk/glossary/gamma-radiation)
- [alpha radiation](https://www.gradenine.co.uk/glossary/alpha-radiation)

## Related

- [Revision notes for Eduqas GCSE Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/radioactive-tracers-are-used-in-medicine-bdc5b598) · Published by Druglandscape Ltd.