fig1
Figure 1. 5-Aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) via the heme biosynthetic pathway. Utilization of PpIX for photodynamic therapy (PDT) or fluorescence-guided surgery (FGS) is illustrated. PBG: porphobilinogen; FECH: ferrochelatase; 0PpIX: ground state porphyrin; 1PpIX: singlet excited state porphyrin; 3PpIX: triplet excited state porphyrin; 1O2: photogenerated singlet oxygen
