UNSCEAR DATA COLLECTIONS ON MEDICAL RADIATION EXPOSURES - TRENDS AND CONSEQUENCES

UNSCEAR evaluates medical radiation frequencies and effective doses (E ) or effective dose equivalents (H-E) at four health care levels (I = industrialised countries, IV = poor developing countries). The 1993 Re port is fairly complete for levers I and II. Effective doses for speci fic procedures may differ from effective dose equivalents by a factor of 2, but for entire practices E and H-E are similar. For most X ray e xaminations, doses at level I decrease but computed tomography (CT) do ses are increasing, resulting in an overall annual per caput H-E of 1 mSv. Doses at levels II, In and IV are 0.1, 0.1 and 0.04 mSv (worldwid e average 0.3 mSv). For nuclear medicine, the annual per caput H-E is 0.09, 0.008, 0.008 and 0.008 mSv at levels I-IV (worldwide average 0.0 3 mSv). For the first time, UNSCEAR now also estimates effective doses in radiotherapy (excluding dose to target). These are 0.7, 0.2, 0.03 and 0.02 mSv annually per caput at levels I-IV (average 0.3 mSv) for t ele- and brachytherapy, much less for therapeutic nuclear medicine (av erage 0.002 mSv). These doses cannot be directly compared to diagnosti c doses, but therapy should not be disregarded in dose statistics. UNS CEAR draws no radiation protection conclusions. However, its data sugg est that attention should be paid to CT, to paediatric X ray examinati ons, to repeated X ray examinations of small subsets of populations, t o fluoroscopy and to choice of diagnostic radiopharmaceuticals in deve loping countries.