Table 4.

Time trends in estimated mean and median annual film badge doses (mSv) in U.S. radiologic technologists working in hospitals during 1926–84 and summary of annual uncertainty distributions of badge dose.

Calendar perioda	Medianb	Meanb	Geometric standard deviationc
≤ 1939	71	100	2.4
1940–49	16	25	2.5
1950–59	11	28	3.9
1960–76	2.2	3.6	2.7
1977–84	2.0	2.3	2.3

Modified from Simon et al. Radiat Res 2006;166:174–92.

^aCalendar year periods were chosen based on reports from the literature and availability and reporting format of dose data from the largest commercial dosimetry provider in the U.S.

^bMedian and mean are based on model predictions (only) within each calendar year period prior to 1977. For 1977–87, mean and median include both film-badge measurements and model predictions.

^cValue of geometric standard deviation for all periods is based on variability of model predictions among cohort members working during the specific period. If subject had a film badge measurement, the geometric standard deviation was assumed to be 1.2.