Indian Journal of Science and Technology
Year: 2009, Volume: 2, Issue: 1, Pages: 1-11
Kimio Tanaka*1 , Natarajan Gajendran2,3 and Nanao Kamada4
1Department of Radiobiology, Institute for Environmental Sciences, Hachazawa 2-121, Takahoko, Rokkasho, Kamikita, Aomori 039-3213, Japan.
2Department of Cancer Cytogenetics, Research Institute for Radiation Biology and Medicine, Hiroshima University.
3Department of Biology, Eritrea Institute of Technology, Mainefhi, Eritrea.
4Hiroshima Atomic Bomb Relief Foundation, 50-1, 3 Chome Asakita-ku, Hiroshima 739-1743, Japan
*Author for the correspondence
Department of Radiobiology, Institute for Environmental Sciences, Hachazawa 2-121, Takahoko, Rokkasho, Kamikita, Aomori 039-3213, Japan. E-mail: kmtanaka@ ies.or.jp
The relative biological effectiveness (RBE) of 252Cf neutrons at different dose rates (2, 0.2 & 0.02 cGy/min) was assessed in human lymphocyte and bone marrow cells using cytogenetic end points (by Giemsa staining). The RBE values for 1 Gy of 252Cf neutrons for chromosomal aberration yield in lymphocyte at the dose rates of 2 and 0.02 cGy/min were 3.3 and 12.0, respectively, in comparison to that of 60Co γ - or 137Cs γ -rays. RBE values of Cf(n) in human bone marrow were determined for the first time in the present study, and were 6.5 for chromatid-type and 4.4 for chromosome-type aberrations at the dose rate of 2 cGy/min. These values were higher than those of lymphocytes obtained in the present study. As studied by FISH method, the exposure of 252Cf neutrons and 60Co γ - and 137Cs γ -rays at different dose rates also revealed the fact that the ratio of the dicentric chromosome yield to the translocation yield was influenced by LET and dose rates. No dose rate effect was found for the induction of dicentric chromosome aberrations. But an increase in the incidence of translocation was observed in the 252Cf neutrons exposure at a dose rate of 0.02 cGy/min. These results suggest that the formation of dicentrics and translocations differed with source of radiation and dose rate.
Keywords : 252 Cf neutrons, dose rate effect, FISH, translocations, low dose rate, biodosimetry, bone marrow, chromosome aberrations
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