Table 2.

The survival fraction of U87 and U251 cells after X–ray irradiation under normoxia and hypoxia for 16 h.

SFa (Mean±SEMb)		2Gy	4Gy	6Gy	8Gy
U87	Normoxia	0.60 ± 0.06	0.31 ± 0.02	0.18 ± 0.03	0.06 ± 0.00
	Hypoxia	0.92 ± 0.04	0.63 ± 0.05	0.32 ± 0.02	0.16 ± 0.01
U251	Normoxia	0.64 ± 0.01	0.32 ± 0.03	0.14 ± 0.01	0.07 ± 0.00
	Hypoxia	0.83 ± 0.05	0.45 ± 0.06	0.21 ± 0.01	0.07 ± 0.02

^asurvival fraction;

^bstandard error of the mean