# A doctor uses a gamma-emitting radioactive isotope to carry out chemotherapy on a patient who has a tumour. Explain why a gamma emitter is chosen for this purpose, and explain one disadvantage of this treatment for the patient.

> OCR A-Level Physics A (H556) — 6.4 Medical imaging · Explain · 5 marks

> Gamma radiation is used in medicine to treat cancerous tumours. The radiation is directed at the affected area of the body from outside.

## Mark scheme (5 marks)

1. Gamma radiation is the most penetrating type of nuclear radiation
2. So gamma radiation can reach the tumour / cancerous cells deep inside the body
3. The gamma radiation is absorbed by the cancerous cells
4. This kills the cancerous cells / destroys the tumour
5. Surrounding healthy cells may also be irradiated and destroyed, causing harmful side effects

## Related

- [Revision notes for OCR A-Level Physics A (H556)](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-doctor-uses-a-gamma-emitting-radioactive-f5c61548) · Published by Druglandscape Ltd.