# Explain why gamma radiation is more hazardous to living cells than alpha radiation when a radioactive source is located inside the human body.

> OCR GCSE Physics A: Gateway Science (J249) — P4.4 Uses and hazards of radiation · Explain · 4 marks

> Nuclear medicine uses radioactive sources placed inside the body to treat certain cancers. Doctors must carefully choose which type of radiation the source emits to minimise unintended harm to healthy tissue.

## Mark scheme (4 marks)

1. Alpha radiation has high ionising power / ionises cells strongly
2. Alpha radiation has a very short range / is stopped by a few centimetres of air or by soft tissue, so causes concentrated damage locally
3. Gamma radiation has low ionising power / ionises cells weakly
4. Gamma radiation is highly penetrating and passes through the whole body, so it can irradiate and damage a much larger volume of healthy tissue / organs

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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/explain-why-gamma-radiation-is-more-04410592) · Published by Druglandscape Ltd.