@article {Bourdeau117, author = {Ccile Bourdeau and Mathilde COLOMBIE and Sebastien Gouard and mathieu FRINDEL and Aurelien Vidal and Michel CHEREL and Fran{\~A}{\textsection}oise Kraeber-bod{\~A}{\textcopyright}r{\~A}{\textcopyright} and Micka{\~A}{\guillemotleft}l BOURGEOIS}, title = {Focus on the controversial aspects of 64Cu-ATSM in tumoral hypoxia mapping by PET imaging}, volume = {58}, number = {supplement 1}, pages = {117--117}, year = {2017}, publisher = {Society of Nuclear Medicine}, abstract = {117Objectives: Tumor hypoxia has been widely reported as a poor prognostic indicator in cancer and is often associated with tumor aggressiveness, chemo-and radio-resistance. An accurate diagnosis of hypoxia is is crucial for providing accurate treatment for patients{\textquoteright} survival benefits. Positron emission tomography (PET) imaging can be used to get a mapping of tumor hypoxia but this still remains a great challenge since precise functional information of the biological processes is needed for many effective therapeutic strategies. This challenge has led to the emergence of new and novel PET tracers for the functional and metabolic characterization of tumor hypoxia non-invasively. Among these tracers, copper semicarbazone compound [64Cu]-diacetyl-bis(N4-methylthiosemicarbazone) (64Cu-ATSM) has been developed as a tracer for hypoxia imaging.Methods: 64Cu (T1/2=12.7h) is produced by the Arronax cyclotron using a deuteron beam of 16 MeV incident energy through the 64Ni(d,2n) reaction. Target preparation, extraction and purification as well as reprocessing, 64Cu-ATSM radiolabeling and quality control procedures have been developed on site. 64Cu-ATSM in vitro development, pre-clinical testing and particularly its affinity in different cell lines and also the controversial reports on its specificity for hypoxia imaging have been also studied.Results: 64Cu with good characteristics to tobe used for antibody labelling have been obtained. This material is used in numerous preclinical studies in France. 64Cu-ATSM - more than a hypoxic tracer, exhibits tracer accumulation in tumor, which is linked to the redox potential and reactive oxygen species. 64Cu-ATSNM appears as a marker of over-reduced cell state and thus an indirect marker for hypoxia imaging. The affinity of 64Cu-ATSM for over-reduced cells was observed to be a complex phenomenon.Conclusion: 64Cu is now available in many countries worldwide with a quality and availability allowing starting preclinical and clinical studies. 64Cu-ATSM seems to be a marker of over-reduced cell state. More in vivo studies are needed to prove the diagnostic utility of 64Cu-ATSM.and to provide a definitive and convincing mechanism for this molecule. Research Support: Acknowledgements: This work has been supported in part by grants from the French National Agency for Research called {\guillemotleft} Investissements d{\textquoteright}Avenir {\guillemotright} Labex IRON n{\textdegree}ANR-11-LABX-0018-01 and Equipex Arronax plus n{\textdegree}ANR-11-EQPX-0004.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/58/supplement_1/117}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }