Doctors treating tumours have to weigh up the risks of potential radiation damage to healthy cells against the benefits of "killing off" the tumour. Each case is treated individually and follows health protection agency (HPA) guidelines.
The HPA is an independent body that protects the health and well-being of the public. Radiation protection is one of its responsibilities. It gives advise on all types of radiation, both ionising and non-ionising, and it takes part in discussions on national recommendations before they become law.
How does the HPA decide what to recommend? They use risk-benefit analysis guided by three main principles:
- Justification – risk justified by benefits
- ALARA – this stands for As Low As Reasonably Achievable. The aim is to keep any radiation exposures as low as possible.
- Dose limits – these are set for all activities; above the set limit, the radiation risk would be unacceptable.
Even with low dosage radiation the effects are cumulative. Doctors, dentists, radiologists and nurses must protect themselves with lead screens as they are exposed everyday whereas a patient will only be treated or scanned a few times in a life time.
Where the jury is still out
Whilst microwaves have lower energy than visible light there remain some concerns about the safety of devices reliant on them such as mobile phones and microwave transmitters. People are not great at judging risks. See Will it happen to me? for more details.