Abnormal translocator protein 18 kDa (TSPO) expression in brain is markedly detected in activated microglia, choroid plexus, and reactive astrocytes [1]. The selective TSPO-binding ligand can provide a powerful imaging tool to detect and monitor inflammatory brain disorders, because TSPO expression is significantly lower in the normal brains [2]. Herein, we have designed an aromatic fluorine substituted imidazo[1,2-a]pyridine analogue, [18F]BS224 and presented its radio-synthesis and bioevaluation for PET imaging of neuroinflammation. Aromatic [18F]fluorination of [18F]BS224 was conducted by two different precursors and conditions: i) diaryliodonium salts by using condition A; ii) pinacol boronate ester by using condition B [4]. Finally, aromatic [18F]fluorination of [18F]BS224 was successfully optimized by nucleophilic substitution of the pinacol boronate ester precursor using [18F]fluoride with copper catalysts. The results, together with those obtained on in vitro TSPO binding, stability, in vivo PET imaging studies with specific and selective binding for TSPO, and a clear visibility of inflammatory lesion in animal models support the conclusion that [18F]BS224 is a promising TSPO PET imaging agent for neuroinflammation. Reference : [1] B. Scatton, et al. (1987) Brain research, 421, 167-172. [2] G. Kreutzberg, et al. (1997) Journal of neurocytology, 26, 77-82. [3] K. Sang Eun, et al. (2011) Organic & biomolecular chemistry, 9, 8346-8355. [4] V. Gouverneur, et al. (2014) Angewwandte chemie, 126, 7885-7889.