A beam of gamma rays is used to treat a tumour. The beam is aimed at the tumour from several different directions.
Why is this done?
The tumour gets a large dose, but healthy tissue gets a much smaller dose
The gamma rays become alpha particles, which are more ionising in tissue
The tumour becomes contaminated, so it keeps receiving radiation later
The healthy tissue gets a large dose, so it can repair the tumour faster
48 exam-style questions on OCR GCSE Physics 6.2 Uses and hazards, covering 6.2.1 Contamination and irradiation, 6.2.2 Half-life and radiation hazards, 6.2.3 Medical uses of nuclear radiation, 6.2.4 Nuclear fission and chain reactions, and 6.2.5 Nuclear fusion. Each one has a worked solution and a mark scheme showing where the marks go.