SECTION 7 RADIATION DOSE DETERMINATION The preceding three chapters have summarized the atmospheric nuclear tests and operations, radiation safety at the nuclear tests, and the postwar occupation of Hiroshima and Nagasaki. This chapter focuses on radiation dose determination for DOD personnel exposed to ionizing radiation as a result of their participation in atmospheric nuclear weapons testing or the postwar occupation of Hiroshima and Nagasaki. The narrative outlines general proce- dures, the identification of unit locations and activities, the use of film badge doses, statistical methods for dose determination, and the reconstruction of radiation doses. 7.1 PROCEDURE. The primary procedure used by Nuclear Test Personnel Review (NTPR) researchers to determine the radiation doses of exposed individuals was through the film badge. Film badge dosimeters were generally issued to scientific personnel, both military and civilian, to personnel expected to be exposed to significant amounts of radiation, and to representative personnel, if not all personnel, in troop and naval units with common activities and relationships to the radiological environment. Before using a film badge reading for dose determination, researchers had to ascertain that the badged period covered the entire period of exposure. Second, if representative badging was used, they had to determine that the activities--locations, times, protection--of the badged personnel adequately represented the activities of the group as a whole, in order that all personnel in the group could be judged to have received the dose(s) of the representative badge(s). If a large number of personnel in an exposed group were badged, a statistical examination of film badge doses could be used to determine the mean dose, the variance, and the confidence limits. An estimated dose, equal to a high (usually 95 percent) probability that the actual exposure did not exceed the estimate, could then be assigned to unbadged personnel. 165