Integrating semiconductor detectors with high energy and spatial resolution is vital for advancing nuclear medicine imaging. Perovskite semiconductors afford unprecedented opportunity for reshaping radiation detection technologies. Nevertheless, perovskite semiconductors have yet to prove their ability in single photon γ-ray imaging, which is essential for enabling nuclear medicine imaging. Herein, we present a pioneering approach to develop high resolution perovskite CsPbBr detectors with pixelated configuration capable of imaging single γ-ray photons for nuclear medicine applications. Eliminating charge transport losses at the surface results in exceptional performance uniformity and long-term device stability, which confers near-unity charge collection efficiency and enhanced spectral resolving capabilities. Record energy resolutions are achieved as 2.5% at 141 keV and 1.0% at 662 keV. Single photon imaging with single point and line Tc γ-ray sources showcases the high sensitivity of 0.13%~0.21% cps/Bq. Phantom imaging distinctly delineates individual column sources spaced 7 mm apart, indicative of an impressive spatial resolution of 3.2 mm. These findings lay the groundwork for integrating perovskite detectors into nuclear medicine γ-ray imaging systems, offering a balance of cost-effectiveness and superior performance.