The “Isotope Technologies” (IT) company has acquired significant experience in the implementation of the strategy of replacing radioactive sources with Alternative Technologies in the scope of the U.S. Office of Radiological Security (ORS) Program in Belarus. During 2019-2020, IT has removed and replaced isotopic irradiators at three facilities. Two facilities are medial facilities which housed Cesium blood irradiator devices; another one was a research laboratory for biological irradiation. Two IT teams coordinated to accomplish the removal and replacement: one team was responsible for decommissioning Cs-137 radiator devices, and the other for Blood Irradiator X-Ray device installations. The main challenge for the first team was to remove the radioactive sources safely and transport them to the national waste disposal facility. The installation team challenge was to rapidly install the X-ray devices (to minimize interruption of blood irradiation and research operations) during the systems exchange period. An additional challenge was the quick and smooth retraining of site personnel to the new alternate technology. Much of the success came from three sequential steps: preliminary project promotion, quick and smooth device exchange, and training of personnel. We would like to share our experience and lessons learned during the safe decommissioning of Cesium 137 irradiators and replacement with alternative X-Ray technologies.