Fig. 4

Exemplarily T1-weighted axial MR-images measured 6 min after contrast agent injection. HI-tumors were either treated (upper tumor in each image) or untreated (lower tumors). Tumors were measured before RT (Day 0) and at 4 time points after single doses. Due to the fast growth of untreated tumors, a longer follow-up was not possible. In (a) 37 Gy isodoses of photons and ¹²C-ions are compared whereas in (b) isoeffective doses with respect to local control at 300 days are shown (18 Gy ¹²C-ions vs. 37 Gy photons and 37 Gy ¹²C-ions vs. 75 Gy photons, respectively). A volume increase was seen only in untreated tumors. The light contrast showed edema, whereas dark volumes are a sign for necrotic areas