Current Levels of Gonadal Irradiation from a Selection of Routine Diagnostic X-Ray Examinations in Great Britain

摘要

The gonadal doses from 13 types of diagnostic examination have been measured at 21 hospitals throughout the country in preparation for a new assessment of the genetically significant dose to the population of Great Britain from diagnostic radiology. Thermoluminescent dosemeters, consisting of lithium borate powder contained in adhesive polythene sachets, were used for the measurements. They were attached to patients to monitor the testes dose directly or the entrance skin dose at the level of the ovaries. Skin doses were converted to ovarian doses using factors obtained by measurements in an anthropomorphic phantom exposed to a range of typical diagnostic X-ray fields. The results indicate that for some types of examination there has been an increase and for others there has been a reduction in the mean gonadal dose delivered per examination since a similar survey was made 20 years ago. Individual gonadal doses for the same examination still ranged over 3 or 4 orders of magnitude throughout the country with distributions described by coefficients of variation that were no less than those found in the late 1950s. This large variability in patient exposure, together with the observation that examinations were satisfactorily conducted on children with a much higher degree of gonadal protection than that offered to young adults, indicates that many patients must be receiving doses that are unnecessarily high. (Atomindex citation 12:585253)