Table 1.
Parameters | Cranium | Cranium | Upper spine | Lower spine |
---|---|---|---|---|
Proton energy at nozzle entrance (MeV) | 180 | 180 | 160 | 160 |
Range in patient (cm H2O) | 16 | 15.7 | 10.9 | 10.7 |
SOBP width (cm H2O) | 16 | 16 | 5 | 6 |
Gantry angle (degree) | 255 | 105 | 180 | 180 |
Air gap (cm) | 10.8 | 11.3 | 11.5 | 11.8 |
Aperture thickness (cm) | 6 | 6 | 4 | 4 |
Proximal margin around CTV (cm) | 0.3 | 0.3 | 0.3 | 0.4 |
Distal margin around CTV (cm) | 0.8 | 0.8 | −0.2 | 0 |
Ratio of field size to brass aperture size | 0.6 | 0.6 | 0.34 | 0.38 |
SOBP denotes spread-out break peak; CTV denotes clinical target volume.