Figure 2

Baseline PpIX levels pALA and levels ≥ 48 h aALA. The differences in PpIX levels pALA between HCTR, HCTRw, pHGG, and rHGG were not significant (Kruskal–Wallis: p = 0.121). Only the PpIX level in pHGG 48 h aALA was significantly higher than the baseline in all groups (MWU: p < 0.001).