Table 1.

Alpha and beta values, α/β ratios, OERs, and DNKu70 ERs

				Dose (Gy) and OER				DNKu70 ER
Cell line	α ± SE	β ± SE	α/β ± SE		SF 0.5	SF 0.1	SF 0.01	SF 0.5	SF 0.1	SF 0.01
Oxic cells
Rat-1
Single cell	−0.150 ± 0.052	−0.0142 ± 0.006	10.55 ± 5.80	Dose	3.5	8.5	13.5
3-day colony, 0 h	−0.263 ± 0.033	−0.0145 ± 0.004	18.13 ± 5.33	Dose	2.3	6.5	10.9
3-day colony, 6 h	−0.121 ± 0.028	−0.0221 ± 0.003	5.47 ± 1.52	Dose	3.5	7.8	12.0
DNKu70-7
Single cell	−0.223 ± 0.037	−0.0275 ± 0.004	8.11 ± 1.85	Dose	2.4	6.0	9.5	1.46	1.42	1.42
3-day colony, 0 h	−0.279 ± 0.031	−0.0212 ± 0.004	13.16 ± 2.72	Dose	2.1	5.8	9.6	1.90	1.12	1.14
3-day colony, 6 h	−0.256 ± 0.043	−0.0196 ± 0.005	13.08 ± 3.99	Dose	2.3	6.1	10.1	1.52	1.28	1.19
DNKu70-11
Single cell	−0.127 ± 0.032	−0.0261 ± 0.003	4.87 ± 1.34	Dose	3.3	7.3	11.1	1.06	1.16	1.22
3-day colony, 0 h	−0.198 ± 0.030	−0.0201 ± 0.003	9.85 ± 2.03	Dose	2.7	6.8	11.0	0.85	0.96	0.99
3-day colony, 6 h	−0.181 ± 0.061	−0.0232 ± 0.006	7.82 ± 3.30	Dose	2.8	6.8	10.7	1.25	1.15	1.12
Hypoxic cells
Rat-1
3-day colony, 0 h	−0.0611 ± 0. 0071	−0.0018 ± 0.0003	33.94 ± 6.55	Dose	9.0	22.6	36.4
				OER	3.9	3.5	3.3
3-day colony, 6 h	−0.0627 ± 0.0008	−0.0014 ± 0.0000	44.79 ± 1.10	Dose	9.2	23.9	39.1
				OER	2.6	3.1	3.3
DNKu70-7
3-day colony, 0 h	−0.0718 ± 0.0057	−0.0026 ± 0.0002	27.62 ± 2.19	Dose	7.6	19.1	30.6	1.38	1.30	1.26
				OER	3.6	3.3	3.2
3-day colony, 6 h	−0.0970 ± 0.0343	−0.0017 ± 0.0001	57.06 ± 15.58	Dose	6.4	18.0	30.7	1.44	1.33	1.27
				OER	2.8	3.0	3.0
DNKu70-11
3-day colony, 0 h	−0.0923 ± 0.0130	−0.0023 ± 0.0004	40.77 ± 9.12	Dose	6.5	17.5	29.1	1.32	1.29	1.25
				OER	2.4	2.6	2.6
3-day colony, 6 h	−0.1190 ± 0.0358	−0.0017 ± 0.0011	69.96 ± 21.56	Dose	5.4	15.8	27.7	1.70	1.51	1.41
				OER	1.9	2.3	2.6

Abbreviations: OER = oxygen enhancement ratio; ER = enhancement ratio; SF = surviving fraction.

Data obtained from single dose–cell survival curves for Rat-1 and DNKu70 cells irradiated under oxic and hypoxic conditions. 0 h and 6 h indicate that cells were trypsinized immediately or 6 hours after irradiation.