A method for positron emission imaging is described. A portion of an imaging subject containing a radiopharmaceutical labeled with positron emitting radionuclide is disposed between and in close proximity with a pair of gamma detectors in opposing positional relationship. Pairs of coincidence gamma rays emitted from positron annihilation events are recorded by the pair of gamma detectors. The gamma detectors are scanned over and across an area of interest of the imaging subject while their position information is recorded. The recorded gamma ray events at each scan interval are used to represent two dimensional image of positron emitting radionuclide distribution within the imaging subject.