Table 2. Radiosensitivity enhancement factor (REF) and dose reduction values.
| Cell type | Radiation type | REF value | Dose reduction (%) |
|---|---|---|---|
| Huh7 | γ-ray | 1.68 | 40.4 |
| C-ion 13keV | 1.28 | 21.6 | |
| C-ion 70keV | 1.72 | 41.9 | |
| HepG2 | γ-ray | 1.22 | 17.9 |
| C-ion 13keV | 1.33 | 25.0 | |
| C-ion 70keV | 1.60 | 37.5 |
The radiosensitivity enhancement factor (REF) corresponding to 90% cell killing was calculated to quantify the radiosensitization due to metformin using the equation. REF = radiation dose for 90% killing/radiation dose in the presence of metformin for 90% killing.