Mount Sinai Experience in Reducing and Removing the Risks of Malicious Use of Radioactive Materials

摘要

Since September 11, 2001, the United States government has been making efforts to minimize the risk of terrorist attacks using Radioactive Dispersal Devices (RDD). Due to the unique characteristics of the cesium chloride (Cs-137) used in medical and research irradiators, it could be potentially used as an RDD. To reduce the risk of malicious use of radioactive materials. Mount Sinai at New York City has adopted several measures. Since 2010, we started to prepare for possible radiological emergencies. We had drills with the Fire Department and Police Department; we purchased equipment to detect, survey, and decontaminate radioactive materials; we implemented enhanced security in facilities having radioactive materials in quantities of concern with the collaboration with the US Department of Energy (DOE); biometric systems. 24/7 video monitoring devices, and radiation detectors with alarm (RMS system) have been installed. The Radiation Monitoring System (RMS) is connected to local law enforcement agencies (LLEA) so that the armed force can intervene timely. Another measure was to limit the number of people who can access the radioactive materials in quantities of concern. A single individual was designated to irradiate the specimen for all the researchers to reduce the number of people accessing the irradiators. The adoption of these measures has reduced the risk significantly already; however, the best way to remove the risk of these radioactive materials being used as an RDD permanently is to find alternative technology to replace these high-activity radioactive sources. Mount Sinai physicists started comparison studies of radiation dose distribution between the cesium irradiators and x-ray irradiators. Five different comparison studies using cells and mice in both cesium irradiators and x-ray irradiators were performed and the results were comparable. As a result. Mount Sinai decided to completely remove all the cesium irradiators and replace them with x-ray irradiators. Mount Sinai successfully removed two of the four cesium-137 irradiators in 2016 through the Off-site Source Recovery Program (OSRP). One of the removed irradiators was a blood irradiator and the other one was a biomedical research irradiator. Two x-ray irradiators were installed to replace these cesium irradiators. In 2017, Mount Sinai continues the comparison studies side by side. After 2 months of operations, 895 bags of blood specimen were irradiated without any x-ray downtime or interruption in operation of the x-ray blood irradiators. Presently we are scheduling the permanent removal of last blood irradiator. Our plan is to have Mount Sinai free of remaining radioactive irradiators soon.