Radionuclide production mode

Table 5 Examples of radionuclides and their production mode...

Radionuclidic impurities in the eluate are directly related to the production mode of parent Mo. In any case, Mo is the most important impurity. The limit of contamination with stated in the Ph. Eur. is 0.1% of the total eluate activity. With irradiation-produced molybdenum-99, other radionuclidic impurities are limited to 0.01% of the total radioactivity. Identified impurities include Sn-113, Au-198, Au-199, Cs-134, and Nb-92. 

Several radionuclides, radioactive isotopes that decay to noble gases, are listed in Table 1. In a radioactive decay, the radioactive isotope is referred to as the parenf isotope, while the decay product, the noble gas isotope, is referred to as the daughter isotope. In some cases listed, there is more than one mode of decay possible. In other cases, a single decay starts a chain that will ultimately produce several noble gas atoms. To take both into account, the yield (the number of noble gas atoms produced for each parent atom) is also given. Finally, radionuclides that fission may produce any of the several different isotopes of Xe in a characteristic spectrum (Table 2). All of the systems listed, with the exception of the decay of U and Th to Xe, have been exploited in extraterrestrial samples at one time or another. 

The production of a radionuclide becomes the basis of activation analysis methodology. In effect, a radioisotope is formed when the nuclei of any stable isotope is exposed to a source of neutrons or any other particle. The thermal neutron reaction upon Na-23 can be used to illustrate this mode of formation ... 

A list of reactor-produced radionuclides of current interest to nuclear medicine is given in O Table 38.1 along with modes of production and corresponding nuclear cross sections. From this list, the production and a brief description of chemical processing of the following radionuclides will be discussed ... 

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