Diagnostic radiology in Norway from 1983 to 1993 - Examination frequency and collective effective dose to patients

Radiological activity in Norway has been investigated by means of three surveys in 1983, 1988 and 1993. The patient doses from conventional X ray examinations were assessed from more than 5000 measurements of area-exposure at 50 hospitals, using conversion coefficients from the National Radiological, Protection Board (NRPB) in the UK. The total collective effective dose (CED) to patients from diagnostic radiology in 1993, including contributions from computed tomography and mammography, was assessed to be about 3400 man.Sv (0.78 mSv per inhabitant). The total frequency of radiological examinations has increased from 641 to 710 per 1000 inhabitants during the past ten years. The most significant trend is the increase in CT examinations, now representing 7% of the total number of examinations, and 30% of the total CED from diagnostic radiology. Conventional examinations of the gastrointestinal tract are decreasing due to the introduction of other procedures, but these examinations still contributed 26% to the total CED in Norway.