Figure 3.

Mean tumor rStO₂ and rBF values in partial responders (PRs; n = 4) expressed as ratios of the baseline readings measured before Ce6 administration at “−3 h”, 3 h prior to the first PDT (A and C) and second PDT (B and D) respectively. The standard errors of the mean are presented as error bars. The trends observed after the first and second PDT were different. The rStO₂ values decreased by only about 15% compared to 40% following the first PDT. Although the rBF levels decreased by about 50%, these values made a quick recovery to almost 80% of baseline values within 48 h.