Manganese: A double agent for imaging ?

Gadolinium (Gd3+) complexes have been used as MRI contrast agents for 35 years, but recently the safety of some was questioned. The replacement of Gd3+ by manganese (Mn2+), a biogenic metal, would enable safer complexes.

Nevertheless, the Mn2+ has to be chelated by complexes exhibiting high thermodynamic stability and kinetic inertness (to guarantee that the Mn is not released in vivo) and with a water molecule directly coordinated to the metal, essential for a good MRI efficiency. Combining these two properties is a chemistry challenge.

The “Metal complexes and MRI” team of CBM and their collaborators from IPHC (Strasbourg) have synthesized and studied a bispidine ligand, a molecule which cavity is well adapted for Mn2+ complexation. This Mn2+ complex has an excellent kinetic inertness and its MRI efficiency was validated by preclinical studies.

52Mn is an emergent radionuclide for positron emission tomography (PET). Mn2+ is the only metal enabling both MRI and PET imaging. The use of 52Mn is nevertheless limited by its low availability and lack of appropriate ligand.

For the first time in France, 52Mn was produced at the Orléans’ cyclotron, and 52Mn-bispidine was successfully obtained.

Overall, bispidine is a very promising ligand for the Mn2+ complexation, for MRI and PET. Due to its outstanding kinetic inertness, in vivo use of Mn2+ without toxicity risk can be anticipated.


See the news on the website of the CNRS Institute for Chemistry.


Eva Toth, Daouda Ndiaye, Maryame Sy, Agnès Pallier, Sandra Même, Isidro de Silva, Sara Lacerda, Aline M. Nonat, Loïc J. Charbonnière Unprecedented kinetic inertness for a Mn2+‐bispidine chelate: a novel structural entry for Mn2+‐based imaging agents - Angewandte Chemie, 2020,


On January 17, 2020, rich exchanges took place between the thematic group "Metal Complexes and MRI" and students of the first and final European class of the Lycée Pothier in Orleans as part of DECLICS "Dialogues Entre Chercheurs et Lycéens pour les Intéresser à la Construction des Savoirs" .

13th Workshop of the “Vectorization, Imaging and Radiotherapy” network of Cancéropôle Grand Ouest – Le Bono, 2019, September 25-28th

The 13th international workshop edition will focus on the latest advances in imaging techniques: PET, SPECT, MRI, US, Infra-red Bioluminescence, Fluorescence, Photoacoustic, CyTof Imaging, Microscopy, Spectroscopy and Raman Imaging.

It aims to address innovative developments in chemistry (synthesis of tracers, chelates, contrast agents, fluorescent probes, etc.), biology (identification of new tumour targets, etc.) and physics (instrumentation, methodological aspects of image analysis, radiomics ...)

The workshop will confront the points of view and problems of the various disciplines, Chemistry, Biology, Physics, Medicine, working for the development of imaging in Oncology.

Overview lectures will be given by experts in the different scientific fields targeted by the workshop. A number of selected oral presentations given by young researchers will complete the different scientific sessions.

This workshop aims at sharing scientific results and at facilitating exchanges between experienced and young researchers in a fast advancing field. The place of the congress was chosen in order to stimulate intense discussions between young and senior scientists.

See workshop site