Cells Treatment α (Gy-1) control β (Gy-2) control α -enhanc factor β -enhanc factor SW1573 ip sham 0.21 ± 0.09 0.061 ± 0.016       1 μM cisplatin (1h) 0.21 ± 0.08 0.072 ± 0.018 1.0 1.2 SW1573 dp sham 0.10 ± 0.09 0.063 ± 0.016       1 μM cisplatin (1h) 0.25 ± 0.09* 0.077 ± 0.017 2.5 1.2 SW1573 ppi sham 0.37 ± 0.12 0.014± 0.034       1 μM cisplatin (cont) 0.41 ± 0.08 0.019 ± 0.025 1.1 1.4   5 μM cisplatin (cont) 0.58 ± 0.20* 0.030 ± 0.008* 1.6 2.1 Siha ppi sham 0.41 ± 0.04 0.01 ± 0.01       1 μM cisplatin (cont) 0.81 ± 0.12* 0.02 ± 0.02 2.0 2.0 Sham is radiation only; ip=immediately plated; dp=delayed plated; ppi=plated prior to irradiation. *Significant from sham p<0.05.

Table 1: Values of the linear-quadratic parameters a and ß and enhancement factors from SW1573 and Siha cells treated with ionizing radiation only and after combined radiation cisplatin (1 µM for 1h; 1 µM continuously; 5 µM continuously) treatment.