Such practices disregard patients' rights and violate basic principles of modern medical practice, argues an expert in this week's BMJ.
Assessing radiological risk is certainly complicated, but some key information should be shared between patients and doctors, writes the author.
He suggests that risk might easily be communicated by expressing the dose as multiples of a chest x-ray and the risk of cancer as number of extra cases in the exposed population. This method has been suggested by the UK College of Radiologists and endorsed by the European Commission's guidelines on imaging. Explanation of dose should also be mandatory for the higher risk investigations, he adds.
Better knowledge of risks will help us to avoid small individual risks translating into substantial population risks, he concludes.