Evaluation of Specific Binding of [11C]RTI-97 to KOR by Autoradiog-raphy and PET Imaging in Rat

International audienceKappa opioid receptor (KOR) PET imaging remains attractive to understand the role of KOR in health and diseases, and to help the development of drugs especially for psychiatric disorders such as depression, anxiety and addiction. The potent and selective KOR antagonist RTI-97 labelled with carbon-11 was previously demonstrated to display specific KOR binding in mouse brain by ex vivo autoradiography studies. Herein, we evaluated [11C]RTI-97 in rat by in vitro autoradiography and by in vivo PET imaging. The radiosynthesis of [11C]RTI-97 was optimized to obtain high molar activities. Despite a low cer-ebral uptake, the overall results showed an heterogeneous repartition and specific KOR binding of [11C]RTI-97 in brain, and a high and specific accumulation of [11C]RTI-97 in pituitary in accordance with KOR expression

Sultone-based radiochemistry for the development of 18F-radiotracers for high performance hypoxia PET imaging

LDM-TEPInternational audienc

[ 18 F]Fludarabine-PET as a promising tool for differentiating CNS lymphoma and glioblastoma: Comparative analysis with [ 18 F]FDG in human xenograft models

CERVOXY/LDM-TEP COLLInternational audienc

Développement et validation préclinique in vivo du [18F]FLUSONIM pour l’imagerie TEP de l’hypoxie de haute performance

CERVOXY/LDM TEPNational audienc

Transport into the central nervous system of [18F]FLT and [18F]Fludarabine for brain tumors

LDM-TEPInternational audienc

Transport into the central nervous system of [18F]FLT and [18F]Fludarabine for brain tumors

LDM-TEPInternational audienc

Delivering FLT to the Central Nervous System by Means of a Promising Targeting System: Synthesis, [11C]Radiosynthesis, and in Vivo Evaluation

LDM TEP COLLInternational audienceThe development of delivery systems to transport some specific radiotracers across the blood-brain barrier (BBB) needs to be investigated for brain imaging. [18F]FLT (3′-deoxy-3′-18F-fluoro-l-thymidine), an analogue substrate of the nucleoside thymidine, has been developed as a proliferation tracer for oncological PET studies. Unfortunately, low-grade brain tumors are poorly visualized due to the low uptake of [18F]FLT in brain tissue, preventing its use in PET imaging to detect brain tumors at an early stage. Based on our previous work, a redox chemical delivery system (CDS) related to Bodor’s strategy was developed to enable the penetration of FLT into the brain. To this end, FLT was covalently linked to a series of lipophilic carriers based on a 1,4-dihydroquinoline structure. To determine the best carrier, various sets of [11C]CDS-FLT were prepared and injected into rats. Pleasingly, in vivo results let us suggest that this CDS is a promising approach to overcome the BBB to target low-grade brain tumors for PET imaging

Chemical Delivery System of MIBG to the Central Nervous System: Synthesis, 11 C-Radiosynthesis, and in Vivo Evaluation

LDM TEPInternational audienceThe norepinephrine transporter (NET) plays an important role in neurotransmission and is involved in a multitude of psychiatric and neurodegenerative diseases. [123I/131I]meta-iodobenzylguanidine (MIBG) is a widely used radiotracer in the diagnosis and follow-up of peripheral neuroendocrine tumors overexpressing the norepinephrine transporter. MIBG does not cross the blood–brain barrier (BBB), and we have demonstrated the “proof-of-concept” that 1,4-dihydroquinoline/quinolinium salt as chemical delivery system (CDS) is a promising tool to deliver MIBG to the brain. To improve BBB passage, various substituents on the 1,4-dihydroquinoline moiety and a linker between CDS and MIBG were added. A series of CDS-MIBG 1a–d was synthesized, labeled with carbon-11, and evaluated in vivo into rats. The in vivo results demonstrated that, although adding substituents on CDS in 1a–c is of no benefit for brain delivery of MIBG, the presence of a linker in CDS-MIBG 1d greatly improved both brain penetration and the release rate of MIBG in the central nervous system