The present invention discloses neurochemical agents and biochemical agents for human or mammalian neuro- and body-metabolic imaging, comprising chemicals involved in neuronal or glial function, neuromodulatory processes in the brain of said human or mammalian, vascular function, or organ specific metabolic processes; said neurochemical and biochemical agents are labeled with stable isotopes selected from a group including carbon-13, nitrogen-15, deuterium, fluorine-19 or a combination thereof in predetermined positions, so as to enhance the detectability of the agents and their metabolic successors.