Key Points
■ Medical radiation currently accounts for an increasing percentage (approximately 50%) of the total radiation exposure for the US population (previously about 15%) (moderate evidence).
■ Children are 2–5 (some cite up to 10) times more sensitive to radiation than adults (moderate evidence).
■ There are no data that prove a direct link between low-level radiation from diagnostic imaging and cancer. The best data regarding long-term effects of low-level radiation (100–150 mSv) exposure come from the longitudinal survivor study (LSS) of atomic bomb survivors (moderate evidence).
■ Most major medical and scientific organizations accept the linear, no-threshold model as the preferred model for low-level radiation and cancer risk estimation.
■ The lifetime risk of fatal cancer from a single (relatively high dose) CT in a child has been estimated to be 1:1000 (limited to moderate evidence).