Nanoparticulate formulation comprises a polyethylene glycol alkyl block-copolymer and a near infra red fluorescent dye. Independent claims are included for: (1) producing the nanoparticulate formulation, comprising dissolving the polyethylene glycol alkyl block-copolymer in water and adding the fluorescent dye to the solution to obtain a micellar formulation; and (2) a phannaceutical device comprising the radiocontrast agent.