An elastic computerized brain atlas was developed for the analysis of positron emission tomography/single-photon emission tomography (PET/SPET) data. It consists of a set of digital anatomical contours and a template of regions of interest, schematically describing the brain, derived from a currently used anatomical/functional brain atlas. A warping algorithm, matching equivalent contours, was implemented to elastically fit the atlas to individual brain images. The elastic computerized brain atlas was applied to representative magnetic resonance imaging (MRI)-PET/SPET studies, MRI providing the anatomical information used by the matching procedure. The atlas is suited for clinical use in a nuclear medicine environment.