Novel hydroxyl dendrimer‐based PET tracer [18F]OP‐801 detects early‐stage neuroinflammation in 5XFAD mouse model with higher sensitivity than TSPO‐PET

Chronic activation of macrophages/microglia plays a critical role in the onset and progression of neurological diseases, including Alzheimer’s. While PET imaging could enable non‐invasive visualization and quantification of activated macrophages/microglia in vivo, most available PET tracers are nonspecific for macrophages/microglia (Lambert, 2009). To address this need, we developed [18F]OP‐801, a synthetic hydroxyl dendrimer‐based PET tracer that is selectively (>95%) taken up by reactive macrophages/microglia across the blood‐brain barrier (Alnasser, 2018). Here, we evaluated the ability of [18F]OP‐801 to detect activated macrophages/microglia in the 5XFAD murine model of Alzheimer’s compared to an established neuroinflammation imaging approach (translocator protein 18 kDa [TSPO]‐PET, using [18F]GE180).