Accession Number : AD0451037


Title :   ACCUMULATION OF LETHAL IRRADIATION DOSES BY FRACTIONATED EXPOSURE TO X-RAYS,


Corporate Author : NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CA


Personal Author(s) : Krebs, J S ; Brauer, R W


Report Date : 22 Sep 1964


Pagination or Media Count : 22


Abstract : The LD50 of mice for exposure to daily fractionated irradiation has been measured for fractionation periods of from 5 to 60 days. The amount of recovery occurring during the fractionation was found to depend largely on the number of dose fractions, rather than on the size of fractions or the total time duration. The amount of recovery did not agree with the model involving exponential decay of injury with time after exposure. The results suggest that the biological basis for the recovery is the prompt repair of sublethal injury to vital cells of the mouse during the intervals between exposures to radiation. The existence of similar recovery patterns in previous studies of dose fractionation is pointed out. The relationship of the present pattern of radiation exposure to other patterns for chronic radiation exposure is discussed briefly. (Author)


Descriptors :   *RADIATION TOLERANCE , RADIATION DOSAGE , X RAYS , LETHAL DOSAGE , RECOVERY , RADIATION EFFECTS , DOSE RATE , RADIATION INJURIES , EXPOSURE(PHYSIOLOGY) , CELLS(BIOLOGY) , MICE , TIME STUDIES , RADIOBIOLOGY


Distribution Statement : APPROVED FOR PUBLIC RELEASE