%0 Journal Article %A L. Labéjof and I. Mororó and P. Galle and G. Barbosa and M.I. Severo and A.H. de Oliveira %D 2010 %J International Journal of Biotechnology and Bioengineering %B World Academy of Science, Engineering and Technology %I Open Science Index 44, 2010 %T Effect of Dose Rate of Irradiation on Ultrastructure of Duodenal Mucosa %U https://publications.waset.org/pdf/1324 %V 44 %X Ultrastructure of duodenum mucosa of irradiated rat was studied versus dose rate of irradiation following exposure to gamma rays from 60-Cobalt source. The animals were whole body irradiated at two dose rates (1 Gy.mn-1 and 1 Gy.h-1) and three total doses (1, 2 or 4 Gy) for each dose rate. 24 or 48 h after irradiation, their small intestine was removed and samples of duodenum were processed for observations under a transmission electron microscopy. Samples of duodenum mucosa of control rats were processed in the same way. For the lower dose rate of 1 Gy.h-1, main lesions characteristic of apoptosis were detected within irradiated enterocytes at a total dose of 2 Gy and 24 h after exposure. Necrosis was noted in the samples, 48 h after exposition. For the higher dose rate of 1 Gy.mn-1, fewer changes were detected at all total doses 24 or 48 h irradiation. Thus, it was shown that the appearance of radiationinduced alterations varies not only with increasing total dose and post-irradiation time but especially with decreasing dose rate. %P 492 - 499