A multimodal PET (positron emission tomography)/MRI (magnetic resonance imaging) contrast agent, a process of synthesizing said PET/MRI contrast agent, and a pharmaceutical formulation comprising said PET/MRI contrast agent are disclosed. The PET/MRI contrast agent comprises a magnetic signal generating core, and a coating portion formed at least partially over a surface of said magnetic signal generating core, wherein the coating portion comprises a plurality of layers, including an inner layer having a functionalized surface, and an outer layer in the form of a radionuclide electrolessly plated layer formed on said functionalized surface.
