Hypoxia imaging and sensing in vivo with endogenous protoporphyrin IX

Endogenous Protoporphyrin IX (PpIX) has been used in multiple applications in medicine, most notably in clinical photodynamic therapy (PDT) and in fluorescence guided-surgery (FGS). However, it also has seen expanded investigative use in other areas where this porphyrin is naturally present or can be induced, such as in bacteria, areas of inflammation or damaged tissues. It also has unique signatures that are being explored in areas such as tissue hypoxia, lymphatic flow, and in therapeutic applications such as neoadjuvant priming or stimulation of healing. This survey examines the unique spectrum of features that this molecule has, and how its ubiquitous metabolic production, combined with its whole body biodistribution and kinetics make it relevant for therapy and/or diagnostics in a range of body sites and conditions.