Central nervous system assessment in nuclear medicine. Clinical aspects: tracers and indications

Nuclear neuroimaging techniques allow the study of functional and neurochemical aspects of the human brain in vivo. SPECT (Single Photon Emission Computed Tomography) as well as PET (Positron Emission Tomography) are non-invasive techniques which present two modalities: functional and biochemical. The functional one provides information about neuronal activity measured through metabolism (PET) or regional brain perfusion (SPECT, RMN f). Biochemical neuroimaging provides information on the chemical substrates involved in neurotransmission (receptors, transporters and enzymes) and allows the study of the synaptic activity through imaging of the different brain regions. This information about neurochemical aspects of neurotransmission is an exclusive field of nuclear neuroimaging techniques SPECT and PET. In this paper we discuss the tracers used for each modality of brain SPECT as well as their main clinical uses. (author)