How much radiation exposure is there with standard imaging tests?

Studies have associated x-ray exposure with thyroid, breast, and lung cancer and leukaemia. We are exposed to a small amount of radiation all the time. Cosmic rays from the heavens, radioactive elements in the soil and air (radon), stone or brick from your house, for example. And you get even more if you fly in jets a lot. The average person receives about 3 mSv of background radiation per year.

But how much radiation exposure is there with standard imaging tests?

Years of
radiation / test
Chest x-ray0.110 days
Pelvis x-ray0.110 days
CT Head28 months
CT Cervical spine31 year
Plain C-Spine0.23 weeks
CT Chest72 years
CT Abdomen/pelvis103 years
CT T&L spine72 years
Plan T&L spine31 year
Millimetre wave scanner (that hands in the air thing at the airport)0.000115 minutes
Scatter from chest x-ray in trauma bay when standing one meter from patient0.000245 minutes

Human exposures to radiation should follow the ALARA principle; that is, be As Low As Reasonably Achievable.  This ensures that the benefits balance the risks.


Emergency Medicine Kenya Foundation (EMKF) is a not-for-profit (NGO) public benefit organisation registered in Kenya