An estimation of the genetically significant dose from diagnostic radiology for the South African population,...

The genetically significant dose was initially defined by UNSCEAR in 1958. The National Radiological Protection Board (NRPB) derived a formula from this definition as shown in the NRPB Report, NRPB-R106. It combines the frequency of radiological examinations obtained during the country-wide survey and estimates of gonadal doses for different examination types, together with population and child expectancy data. The task was set to find a model in order to draw the best representative sample of the population, and it was determined in a unique way, namely the so-called Dollar Unit Sampling method. A sample of 27 institutions out of a possible 292 (9%) was drawn. The GSD for the total South African population was calculated, using the above-mentioned formula, as 95 microGy. The breakdown of the genetically significant dose for the various South African race groups was Asian--229 microGy; black--67 microGy; people of color (mixed race)--112 microGy; and white--463 microGy.