IN FETUSES exposed to 130 roentgens on the 13th day of gestation cellular necrosis in the cerebral vesicles is a consistent occurrence.1-3 Subsequently, reparative processes are evident,1 rosettes are formed, and malformations ensue.2-5 In this study the central nervous system (CNS) of fetuses was examined at intervals from ten minutes to six days following irradiation in utero, and the morphologic features of irradiation-induced cellular necrosis and repair are reported.
Materials and Methods
Pregnant female rats of the Sprague-Dawley strain were exposed to 130 R of whole body x-irradiation on the 13th day of gestation. The radiation was administered from the dorsal aspect with a 300-unit maxitron operated at 250 kilovolt (peak) (KVP) and 15 ma at the rate of 60 R/min. The calibration for appropriate dosage was made with an R meter, placed in a wax phantom at a depth corresponding to the depth of fetuses below