ECUR SUM.TZCT: eS Radiological yqazards From An ABD, Alpha, Beta, and Gamma Rddiation The re The relative biological effectiveness of gamma radiation,as determined in the mouse, is essentially one (1) conpared with a 230 KVP x-ray machine. The RBE for man is not definite. Variations in dose rate from 1 minute to 40 minutes do not essentially effect the biological response. The data has not oeen determined for either extremely high dosages delivered in a short period of time or for chronic dosages, except to indi- cate that ffeld data at very high dose rates in the mid-lethal and lethal ranze correlates well with laboratory calibrations at lower dosage rates. The effective energy of a residual field and its corresponding Ane is under study at the present time, Patnvlogical studies of animals at field tests reveal no essential difference other than for species variation from the pathological exanination of Japanese fatalities at Hiroshima and Tagesaki. The prompt reactions or immediately incapacitating ef ects of vastly super-lethal dosages is unknown. Recent la>oratory work will be discussed at the meeting. Shielding afforded by military structures, including fox holes, ig known or can be roughly calculated for any specific structure. t%. Chronic effects: No information has ceen obtained urder field conditions. A numoer of R and D projects sponsored by various agencies have allowed us to make general predictions as to possible effects. All of these projects, however, have ‘seen done with animals and there is very little data available on man. The NEPA estimates and those appearing in the Handbook on ftomiec Weapons for Medical Officers represent best available information. In general, there seems to be a significant recovery Vollowing radiation injury so that tolerances to integrated chronic dosages ray ve significantly increased over those to single acute exposures. 2. Seta. The measurement of the external beta hazard with currently available instruments is difficult. Various estimates based on laboratory type measurements and theoretical calealations have

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