Figure 2:

Dependence of the dose-response parameters for photons and ¹²C-ions on the tumor subline: The increase of radiation tolerance with increasing tumor grading is stronger for photons than for ¹²C-ions (A). For a given tumor grading, the slope of the dose-response curve is steeper for ¹²C-ions than for photons (B). The effectiveness of ¹²C-ions relative to photons increases with increasing tumor grade (C). These results are essentially independent of uncertainties resulting from the endpoint definition.