An overview of the developments and potential applications of Ga-labelled PET/CT hypoxia imaging.

Non-invasive imaging of hypoxia plays a role in monitoring the body's adaptive response or the development of pathology under hypoxic conditions. Various techniques to image hypoxia have been investigated with a shift towards the use of molecular imaging using PET/CT. The role of hypoxia-specific radiopharmaceuticals such as radiolabelled nitroimidazoles is well documented particularly in the oncologic setting. With the increasing utilisation of in-house labelling with a PET benchtop generator, such as the Ge/Ga generator, the use of Ga-labelled hypoxic radiopharmaceuticals in the clinical setting is developing. Since hypoxia plays a role in various pathologic states including infectious disease such as TB, there is a need to explore the potential application of Ga-labelled hypoxia seeking radiopharmaceuticals beyond oncology. The purpose of this review is to describe the developments of Ga-labelled hypoxic radiopharmaceuticals including the various chelators that have been investigated. Further, the role of hypoxia imaging in various pathologies is discussed with particular emphasis on the potential clinical applications of hypoxia PET/CT in TB.