MEDIAN LETHAL DOSE (LD-50/60) STUDIES IN SHEEP FOLLOWING 250-KVP X-IRRADIATION.
Technical rept. for Aug 61-May 63,
AIR FORCE WEAPONS LAB KIRTLAND AFB N MEX
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Seventy-four sheep, Ovis aries, were subjected to bilateral, total-body, 250-kvp x-irradiation at a dose rate of 7.5 rmin. Doses ranging from 218 to 518 r midline air dose were administered at nine different dose levels. Probit analysis of the mortality data revealed a 50-percent, 60-day LD-5060 lethal dose value of 389 r with 95-percent confidence limits of from 334 r to 437 r. Converting midline air dose to midline tissue dose resulted in the value 245 r with limits of from 210 r to 275 r. All deaths occurred between 16 and 32 days following irradiation. Hematological studies and gross necropsies confirmed the severe involvement of the hematologic system. Author