Synopsis

The National Academies of Sciences, Engineering, and Medicine (the National Academies) were tasked by Sandia National Laboratories with assessing the status of medical, research, sterilization, and other commercial applications of radioactive sources and alternative (nonradioisotopic) technologies in the United States and internationally. The purpose of the study was to support existing and future activities under the National Nuclear Security Administration Office of Radiological Security program to reduce the current use of high-risk radiological materials in these applications and promote use of alternative technologies. The study examined Category 1, 2, and 3 sources, which are the three most hazardous source categories in the five-category system developed by the International Atomic Energy Agency (IAEA). The system ranks the sources primarily in terms of their potential to cause deterministic¹ health effects to a person handling or coming in contact with them if not safely managed or securely protected. The system does not consider stochastic effects, such as future cancer development that could be induced by being in proximity to the radioactive sources if not managed safely and securely or socioeconomic consequences of radiological incidents that involve these radioactive sources. National regulatory agencies, including the U.S. Nuclear Regulatory Commission (U.S. NRC) have adopted IAEA’s source categorization system to regulate the safety and security of radioactive sources.

The National Academies appointed an expert committee to carry out the study and prepare a technical report. The committee used a previous National Academies report on the same topic² as a baseline to assess developments in adoption of alternative technologies to radioactive sources.

The committee found that radioactive sources continue to be used broadly both nationally and internationally and that there are more high-risk (Category 1 and Category 2) sources and likely more Category 3 radioactive sources in the United States today compared to 12 years ago. Although there has been progress with adopting alternative technologies to radioactive sources, adoption has progressed at different rates for different applications, and for some applications no suitable replacement technology has been developed. Therefore, use of Category 1 to 3 radioactive sources is expected to continue in the foreseeable future. Security, tracking, and appropriate end-of-life management are important to reduce risks and increase accountability associated with these sources.

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¹ A deterministic effect is one for which a threshold level of dose exists, and above it, severity of the health effect increases as the dose increases.

²NRC (National Research Council). 2008. Radiation source use and replacement: Abbreviated version. Washington, DC: The National Academies Press.

The committee recommends

• Reframing the radioactive source categorization system to include the potential of sources for probabilistic health impacts and economic and social impacts and making changes to security and tracking of sources, as appropriate.
• Expanding current requirements for financial guarantees to ensure that they adequately cover the end-of-life management for newly licensed radioactive sources and developing a national strategy for end-of-life management for currently owned and orphan radioactive sources.
• Prioritizing funding for research and development projects that aim to develop alternatives to use of radioactive sources in applications where there are currently no acceptable nonradioisotopic alternative technologies.
• Supporting equivalency studies for replacing radioactive sources and adopting an alternative technology.
• Initiating research on alternatives to cesium chloride for calibration applications.

The committee found that alternative technologies do not provide a “one-size-fits-all solution.” This is particularly evident in medical applications across high- and low- and middle-income countries because of the stark disparities in access to health care and resources. Adoption of alternative technologies for cancer therapy in some low- and middle-income countries has had unintended negative effects on patient care because of a lack of required resources and infrastructure that make these alternatives viable options. The committee recommends that efforts by the U.S. government and other national and international organizations to reduce use of high-activity radioactive sources globally and in low- and middle-income countries should be driven by examination of the local infrastructure and needs.