Table 4.
Results for parameter estimates of linear-quadratic dose–response model for simple exchanges, and relative biological effectiveness (RBE) factors for protons of different energies compared to acute or low dose or low dose-rate γ-rays.
| Radiation type | α (Gy−1) | β (Gy−2) | RBEγAcute | RBEmax |
|---|---|---|---|---|
| γ-Rays acute | 0.157 ± 0.013 | 0.092 ± 0.027 | – | – |
| γ-Rays LD | 0.09 ± 0.004 | – | – | – |
| Proton, 5 MeV | 0.132 ± 0.016 | 0.031 ± 0.057 | 0.84 ± 0.1 | 1.5 ± 0.18 |
| Proton, 120 MeVa | 0.121 ± 0.015 | 0.137 ± 0.036 | 0.77 ± 0.1 | 1.36 ± 0.17 |
| Proton, 250 MeV | 0.088 ± 0.009 | 0.064 ± 0.017 | 0.56 ± 0.06 | 1.0 ± 0.1 |
| Proton, 800 MeV | 0.116 ± 0.028 | 0.104 ± 0.049 | 0.73 ± 0.18 | 1.3 ± 0.31 |
| Proton, 1000 MeV | 0.159 ± 0.02 | 0.081 ± 0.023 | 1.01 ± 0.13 | 1.79 ± 0.23 |
| Proton, 2000 MeV | 0.132 ± 0.028 | 0.071 ± 0.058 | 0.84 ± 0.19 | 1.49 ± 0.31 |
| Proton, 2500 MeV | 0.119 ± 0.01 | 0.077 ± 0.015 | 0.76 ± 0.07 | 1.35 ± 0.11 |
a150 MeV proton beam with 5 cm polyethylene shielding leading to residual energy of 120 MeV.