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 on said gantry at an angle of 180 degrees relative to each other; said detector heads mechanically co-registered to each other at said 180Â° angle and maintaining said 180Â° alignment and co-registration during rotation of said gantry; said detector heads geometrically aligned to provide a one-to-one detector pixel correspondence between the two detectors; 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 and multiplying the pixel values of the two co-registered images obtained in the same time bin on a pixel-by-pixel basis to produce a single product image per each time bin.