TY - JOUR T1 - Evaluation of [18F]PBR111 in a rat model of neuroinflammation: A new radiotracer for the TSPO 18 kDa (peripheral benzodiazepine receptor) JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1213 LP - 1213 VL - 50 IS - supplement 2 AU - Nadja Van Camp AU - Fabien Chauveau AU - Raphael Boisgard AU - Benoit Jego AU - Karine Siquier AU - Bertrand Kuhnast AU - Marie Claude Gregoire AU - Andrew Katsifis AU - Frederic Dolle AU - Bertrand Tavitian Y1 - 2009/05/01 UR - http://jnm.snmjournals.org/content/50/supplement_2/1213.abstract N2 - 1213 Objectives To evaluate a new candidate radiotracer for TSPO 18 kDa, [18F]PBR111, using an acute inflammatory rat model. Methods The AMPA rat model (Boutin Glia 2007) was used to study in vitro and in vivo specific and non-specific binding using autoradiography (n=7) and µPET imaging on a Concorde Focus P220 PET camera (n=12), including displacement studies. Results Autoradiography demonstrated a high contrast in the lesion versus the contralateral side (p<0.001), with an ipsi-to-contralateral ratio of 3.9±1.5 that disappeared by adding an excess of PK11195 or PBR111. The binding of [18F]PBR111 was not affected by adding flumazenil, (the ipsi-to-contralateral contrast ratio 4.1±1.4; p=0.4). In vivo PET imaging showed a significantly increased uptake in the lesioned side as compared to the contralateral side, already 6 minutes after injection and up to 60 minutes (p<0.01). Displacement studies with PK11195 and PBR111 showed a rapid and complete displacement of [18F]PBR111 binding from the lesion. Finally, modelisation of the PET data using the “simplified-reference-tissue-model” showed increased binding potential (BP) in comparison to the BP of [11C]PK11195 measured in the same model (2.6±1.1 versus 1.1±0.2, p=0.016). Conclusions Overall, these results support [18F]PBR111 as a promising new and specific tracer of the TSPO 18 kDa. Further preclinical evaluation in preclinical rodent and primate models is underway. Research Support This study was funded by the EU FP6 networks DiMI (LSHB-CT-2005-512146) and EMIL (LSHC-CT-2004-503569). NVC is supported by FWO (Belgium). ER -