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Radiopharmaceuticals for Diagnostics
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Jim Ballinger, Jacek Koziorowski
Technetium-99m (99mTc) is the most commonly used radionuclide for gamma imaging since its introduction ~1970, being used in ~ 85 per cent of nuclear medicine procedures worldwide. 99mTc (t½ 6 h; IT 99.99%; principal γ emission 140.5 keV; 89% abundance) has mainly been produced by decay of Molybdenum-99 (99Mo) in a 99Mo/99mTc generator system. 99Mo (t½ 66 h) is a nuclear fission product of Uranium-235, the [235U](n,f)[99Mo] reaction having a yield of 6.1 per cent. 99mTc is conveniently available on-site from a generator system in which a chromatographic column (generally aluminium oxide) is loaded with 99Mo which continually decays to 99mTc. The two radionuclides can be readily separated because 99Mo remains on the column when it is eluted with 0.9 per cent sodium chloride solution (saline), while 99mTc emerges in the eluate. The ratio between the half-lives of the parent and daughter radionuclides is such that maximal yields of 99mTc are obtained at 24-h intervals, perfect for once-a-day elution. Because of the gradual decay of 99Mo and concomitant reduced yield of 99mTc, the generator is generally replaced on a weekly basis. The generator is autoclaved by the manufacturer and, as long as the end-user maintains aseptic technique, the eluate remains sterile and suitable for direct injection into patients [1].
Adsorption properties of radionuclides on BC3: the first principles study
Published in Molecular Physics, 2022
Nan Zhou, Yong Qin, Jie Tan, Jinjuan Cheng, Shuaixing He, Hai Li, Xijun Wu
With today's scarcity of resources, developing new energy sources such as nuclear power is critical. Nuclear energy development will result in a substantial number of radionuclides. The principal nuclear fission products are cesium, strontium, cobalt, and silver, which are typically found in radioactive effluent from nuclear power plants, spent fuel reprocessing, radionuclide manufacturing facilities, and other sources. They represent a significant threat to human health and the ecology, hence removing radionuclides is critical. So far, various separation techniques have been developed successively, such as chemical precipitation, biological treatment, ion exchange, electrodialysis, membrane separation, evaporation, solvent extraction, and adsorption [1]. Among these methods, adsorption is of great interest because of its simple operation, low cost and low energy consumption. Separation techniques based on physical adsorption using porous materials are a cost-effective alternative to expensive cryogenic distillation [2].