Accession Number : AD0699128


Title :   ACUTE MORTALITY OF MICE AND RATS EXPOSED TO 14 MeV NEUTRONS.


Descriptive Note : Scientific rept.,


Corporate Author : ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD


Personal Author(s) : Strike,T. A.


Report Date : DEC 1969


Pagination or Media Count : 22


Abstract : C57BL mice, C3H mice, and Sprague-Dawley rats were exposed to 250 kVp x rays or 14 MeV neutrons and mortality data collected for 30 days thereafter. The whole-body, bilateral x irradiations over the range of 378 to 918 rads were delivered at approximately 21 rads/min. The whole-body rotational neutron irradiations utilized midline tissue doses in the range from 282 to 707 rads. C57BL mice and Sprague-Dawley rats were exposed at a neutron dose rate which varied from 15 to 35 rads per minute (averages approx. 20 rads/min). C3H mice were exposed at 15-50 (averages approx. 20 rads/min) or 3-5 rads/min to investigate the possibility of dose rate effects. The LD 50/30 values for x rays and 14 MeV neutrons, respectively, were : C57BL mice -- 680 and 432 rads; C3H mice -- 704 and 537 (3-5 rads/min) or 480 (15-50 rads/min) rads; Sprague-Dawley rats -- 810 and 494 rads. The relative biological effectivenesses (RBE) for 14 MeV neutrons using 30-day mortality as the end point for comparison and 250 kVp x rays as the reference radiation were 1.6, 1.5, and 1.6 for C57BL mice, C3H mice, and Sprague-Dawley rats, respectively. A dose rate effect was evident since the LD 50/30 value for C3H mice exposed at 15-50 rads/min was significantly lower (480 rads) than that of mice exposed at 3-5 rads/min (537 rads). Of the strains studied only the mean survival time of C3H mice was significantly less when exposed to 14 MeV neutrons at 15-50 rads/min than when exposed to x rays. (Author)


Descriptors :   (*NEUTRONS, LETHAL DOSAGE), (*RADIATION INJURIES, NEUTRONS), MORTALITY RATES, DOSE RATE, RADIATION DOSAGE, MICE, RATS, WHOLE BODY IRRADIATION, X RAYS, RADIATION EFFECTS


Subject Categories : STRESS PHYSIOLOGY


Distribution Statement : APPROVED FOR PUBLIC RELEASE