Imaging Neuroimmune Dysfunction: From TSPO to Emerging Positron Emission Tomography Targets

Dysregulation of the neuroimmune system is increasingly being recognized as a key contributor to psychiatric illness, but its complexity and the limitations of current methodologies have hindered a clear understanding of its role. Advances in positron emission tomography (PET) molecular brain imaging have significantly expanded our ability to study targets expressed on microglia, the brain's resident immune cells, in vivo. While PET imaging of the 18-kDa TSPO (translocator protein) has been widely used to assess microglial levels and activation, its limitations have driven the development of novel radiotracers targeting more specific microglia-related pathways. In this review, we explore the evolving landscape of PET imaging biomarkers. By advancing our ability to study neuroimmune dynamics, these approaches hold promise for refining diagnostic strategies and identifying novel therapeutic targets for psychiatric disorders.