Approximately 1.800.000 CT examinations are performed every year in Belgium. With a mean dose 0,5 mSv, the annual collective dose from CT could induce up to 450 cancer. This number has to be compared to the 45 000 observed new cancers yearly. The deleterious effect of scanner radiation is thus undetectable among cancers induced by smoking, alcohol, and western diet. Risk from radiation is based on cancer mortality rates observed among atomic bomb survivors who underwent high level radiation. Overestimation of collective radiation risks in the filed of low level radiation (below 0,2 Sv) as used for CT is suspected first because a majority of patients undergoing CT are aged 60 years or more, and second because the numerous defense mechanisms that prevent cancer induction at lowdoses in human bodies are not taken into account by the linear no threshold model of carcinogenesis used as legal rule for risk calculations.