Radioisotopic sources are necessary for instrument calibration in numerous applications worldwide. According to a recent National Academy of Sciences report (NAS) (2021), there are over 19,000 radionuclide specific licenses in the United States alone at research facilities, industrial facilities, universities, hospitals, cancer treatment facilities, and nuclear medicine clinics. The Office of Radiological Security (ORS) encourages and facilitates the adoption of non-radioisotopic alternative technologies, including X-ray generators, electron beam (eBeam), and medical linear accelerators (LINACs), when viable options are available in an application space. Successful adoption of nonradioisotopic alternatives has been demonstrated in technologies used for blood irradiation, radiation for scientific research, sterile insect technique (SIT), and medical device sterilization. However, radioisotopic instrument calibration is an application that has not made this transition, in part due to a current lack of viable non-radioisotopic alternatives. Calibration systems with precise and traceable decay rates and energies are critical for periodic calibration and verification of proper device function of radiation technologies. End users and organizations that provide calibration services rely on calibration systems to ensure they are obtaining accurate measurements. Calibration systems primarily consist of IAEA Category 2 cesium-137 (Cs-137) and cobalt-60 (Co-60) sources, which are used to comply with health and safety licensing requirements. The focus of this paper is the current use of calibration systems, their applications, and market availability of non-radioisotopic calibration alternatives.