摘要：Radioresistant E. coli TG1 harboring pUC 18 plasmid which was Ampicillin-resistant was exposed to 60 Co gamma-rays or 3 H beta-rays in saline to determine whether the relative biological effectiveness of 3 H beta-rays is higher than one. After exposure to 60 CO gamma-rays at a dose rate of 0.465 Gy/min, the D 0 by colony formation was 145 Gy in the presence of Ampicillin in or absence from the agar medium; whereas, the D 0 was calculated as 118 Gy with and without Ampicillin after exposure to 3 H beta-rays at a dose rate of 0.431 Gy/min. The relative biological effectiveness established for 3 H beta-rays to 60 Co gamma-rays was 1.23. The reason for the higher effectiveness of 3 H beta-rays as compared to the reference 60 Co gamma-rays is discussed in terms of nascent 0 production.
关键词：RBE; Tritiated water; E.coli; Cell killing; Plasmid DNA
