![]() ![]() Did courageous hospital and university staff work successfully to keep the existence of the sources secret? A more likely possibility is that Daesh did not know about the cobalt 60 sources. Our speculations include that since the cobalt 60 comes in metal form and not as a powder, it would be more difficult to use the radioactive cobalt, involving steps that can be very dangerous for unprepared and inexperienced individuals. We do not know why Daesh did not use the cobalt 60 sources to make a radiological dispersal device. This case has several lessons for the future and should serve as a reminder of the risks posed by radioactive sources, many of which are poorly protected or accounted for. (The source was later found and secured.) 2 However, we estimated that at least one of the cobalt-60 sources in Mosul had a dose rate roughly 20 times greater than the missing iridium. In comparison, a widely publicly discussed radioactive iridium source that went missing in Iraq in late 2015 was also category 2. For individuals within 0.1 meter distance, it could occur within 2-3 minutes. We estimated based on open source information that the cobalt 60 had decayed considerably but still had a radioactive strength that would place it in the International Atomic Energy Agency’s (IAEA’s) category 2 of radioactive sources, described as “very dangerous to the person.” 1 In terms of dose strength, the sources could produce a fatal dose to an individual at a meter from the source within 2-4 hours. These machines were procured years ago in the 1980s or even 1970s for the treatment of cancer and conducting research. He and his colleagues at The Washington Post recently added greatly to this important story.ĭaesh rapidly seized control of the Iraqi city of Mosul in 2014 and inherited with it, unknowingly to the public, two cobalt 60 teletherapy machines carrying highly dangerous nuclear material. He understood the importance of digging into this story while delaying its publication until the radioactive sources were in safe hands. We want to thank in particular Joby Warrick at The Washington Post, who we had alerted early on for assistance in researching the fate of these sources. We are very relieved that these two, older albeit still dangerous, cobalt 60 sources were not found and used by Daesh. As we learned more, we updated our study, which remains a confidential report due to its sensitivity. At the same time, we decided not to publish any of our results. We produced a confidential research study that we used to alert the United States and other friendly governments of the situation as we knew it, most of which were also monitoring the situation. We could not know if Daesh was aware of these sources and their potential, or had already taken possession of them. Their investigations found that there were apparently two sources of radioactive cobalt in Mosul that posed a risk of being used in a radiological dispersal device. The result of a few months of study by Sarah Burkhard, a young scientist, and other staff surprised us all. Two years ago, in the summer of 2015, the Institute decided to investigate whether Daesh controlled dangerous radioactive material in Iraq or Syria. ![]() This report is covered by an exclusive Washington Post story, “How ISIS Nearly Stumbled on the Ingredients for a ‘Dirty Bomb,’” by Joby Warrick and Loveday Morris Statement by the Institute for Science and International Security (The Institute) Reports Cobalt 60 Sources in Mosul: Recovery and Lessons for the Future Cobalt 60 Sources in Mosul: Recovery and Lessons for the Future.Sources are usually replaced about once per half-life or about every 5 years for Co-60. This diameter is significantly larger than modern linear accelerator source sizes and causes the Cobalt 60 teletherapy machines to have larger penumbras. Sources are cylindrical in shape with a diameter of 1-2cm and a height of about 2.5cm. Typical sources have an activity of 5,000-10,000Ci which is able to produce a dose rate of 100-200cGy/min for an source-to-axis distance of 80cm. Co-60 is a superior radionuclide to alternatives, such as Ra-226 and Cs-137, because of its higher energy and specific activity (mCi/g) which allows for greater radiation output with a smaller source size. The buildup region of the photon dose distribution extends to a depth of 5mm, providing some skin sparing.Ĭobalt 60 is produced in a nuclear breeder reactor by neutron bombardment of cobalt 59 and has a half life of 5.27 years. Approximately 10% of the source photons are lower energy scattered photons. Cobalt-60 teletherapy units are able to generate a clinical photon beam with a mean energy of 1.25MeV, similar to the mean energy of a 4MeV photon beam generated by a linear accelerator. ![]()
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