AbstractTo advance the design of self‐assembled metallosupramolecular architectures as new generation theranostic agents, the synthesis of18F‐labelled [Pd2L4]4+metallacages is reported. Different spectroscopic and bio‐analytical methods support the formation of the host‐guest cage‐cisplatin complex. The biodistribution profiles of one of the cages, alone or encapsulating cisplatin have been studied by PET/CT imaging in healthy mice in vivo, in combination to ICP‐MS ex vivo.