2012 Volume 61 Issue 7 Pages 389-397
NRU in Canada and HFR in the Netherlands which had been producing the most important medical isotope, 99Mo, were shut down in 2009-2010. As the production of more than 95% of global 99Mo supply were performed in only five research reactors in the world including the two reactors mentioned above, these shutdowns resulted in global supply shortage of 99Mo. Although the medical isotope crisis were alleviated after the two reactors returning to service, all of these five 99Mo producing reactors are approximately 50 years old. Because the remaining life time of these reactors is not so long, the construction of new reactors or the development of new technologies to produce bulk 99Mo, such as the neutron activation of 98Mo in a reactor or charged particle reaction by accelerator, are proposed for the long-term security of supply of 99Mo. The methods using the molybdenum target lead to much lower specific activity of 99Mo compared to the production with fission method. The new chemical processing technologies, such as manufacturing 99mTc-labeled radiopharmaceuticals from such low specific activity 99Mo, are required for the development of domestic practical production of 99Mo.