1. A compact and mobile high resolution single photon planar and SPECT brain imaging system for imaging the brain/neck/head of a patient that has been administered a single photon labeled biomarker comprising: a rotating gantry; two identical compact gamma imaging detector heads mounted on said rotating gantry and mechanically affixed relative to each other; said detector heads mechanically co-registered to each other at an angle of 180 degrees with respect to one another; said detector heads placed on opposite sides of the patient's head with the patient's brain or neck fully encompassed by the resulting active field of view coverage of said detector heads; an arrangement to minimize head movements by the patient during imaging scans; and a data acquisition and processing system for accepting imaging data individually from each of said gamma detection modules for producing tomographic images of the brain/neck/head.