Table 1.
Results for protons and C ions for variations in parameter x, the relative biological effect (RBE) uncertainty factor (for example, x = 1.2 indicates a 20% RBE increment, x = 1 indicates an RBE of 1 etc.), for intended 2-Gy-equivalent fractional doses
| x = 0.95 | x = 1.0 | x = 1.05 | x = 1.1 | x = 1.15 | x = 1.20 | x = 1.25 | |
|---|---|---|---|---|---|---|---|
|
Protons | |||||||
| dH (Gy) | 1.91 | 1.82 | 1.73 | 1.65 | 1.58 | 1.51 | 1.45 |
| % change (=dH/1.82×100) | (105.3) | (100) | (95.2) | (90.9) | (87.0) | (83.3) | (80) |
| ΔdH (Gy) (=dH −1.82) | 0.1 | 0 | −0.09 | −0.17 | −0.24 | −0.30 | −0.36 |
| BED Gy3 per fraction | 3.20 | 3.42 | 3.65 | 3.88 | 4.12 | 4.36 | 4.61 |
| % BED change (compared with x = 1) | 93.7 | 100 | 106.8 | 113.6 | 120.5 | 127.6 | 134.9 |
|
Carbon ions | |||||||
| dH (Gy) | 0.84 | 0.8 | 0.76 | 0.73 | 0.70 | 0.67 | 0.64 |
| % change (=dH/1.82 × 100) | (105.3) | (100) | (95.2) | (90.9) | (87.0) | (83.3) | (80) |
| ΔdH (Gy) (=dH −1.82) | 0.04 | 0 | −0.04 | −0.07 | −0.10 | −0.13 | −0.16 |
| BED Gy3 per fraction | 3.14 | 3.32 | 3.50 | 3.68 | 3.86 | 4.05 | 4.23 |
| % BED change (compared with x = 1) | 94.6 | 100 | 105.4 | 110.9 | 116.5 | 122.2 | 127.6 |
BED, biological effective dose.
dH is the dose of the particle radiation, which is 1.82 Gy (protons) and 0.8 Gy (C ions).
Δ is the physical change in the dose.
Gy3 is the BED units for the case of α/β=3Gy.