Manganese oxide nanoparticles with favorable properties for multi-modalimaging inmedical and non-medical imaging applications are provided. The particles areuseful formulti-modal magnetic resonance imaging and fluorescence imaging. The particlesareuseful as T1 contrast agents in magnetic resonance imaging. The favorableproperties ofthe manganese oxide nanoparticles also make them useful as tracers forsubsurfaceformation characterization. One embodiment provides a process which includesthe stepsof injecting nanoparticles into a discrete subterranean region, and detectingfluorescenceand/or magnetic data of the one or more nanoparticles in a produced fluidwhich includesthe injected fluid and a formation fluid from the subterranean region.
