Risk benefit ratio
In assessing the risk/benefit ratio the rules are:
The potential benefit of the test should always outweigh the risk
A diagnostic imaging examination is indicated only if it is likely to be useful in the management of the patient and if the risk of the procedure is less than the risk of missing a treatable disorder
It is the responsibility of the imaging specialist to ensure radiation dosage during imaging is kept to a minimum according to the ALARA principle (As Low As Reasonably Achievable), while maintaining the diagnostic quality of the examination.