Short-lived radionuclides advantages

The main advantage of the generators is that they can serve as top-of-the-bench sources of short-lived radionuclides in places located far from the site of a cyclotron or nuclear reactor facilities. 

The activities of some isotopes, in particular °Sr- °Y, can also be detected by liquid-crystal spectrometry with the use of the Cherenkov phenomenon [10, 11]. The Cherenkov effect is used to determine beta isotopes emitting particles whose iiniax IS above 500 keV [12]. The main advantage of beta activity determination by the Cherenkov effect is the use of analytical preparation used for another chemical analysis (e.g. calculation of recovery). Moreover, the addition of low energy beta or alpha radiation does not disturb the measurement, thereby lowering the cost of analysis. The weakness of this method is the decreased recovery registration and the decline in information about the realistic appearance of the beta spectrum [13]. The determination of beta isotopes in environmental samples is very difficult and requires their chemical isolation. The type of sample and the time of chemical analysis determine the choice of analytical method. Also, the time between contamination and sample collection is important procedures used for samples recently contaminated are different to those used for old samples in which the decay of short-lived radionuclides has aheady taken place [1, 5]. 

On the other hand, if the half-life of the radionuclide is very long compared with the irradiation time that can be applied for practical reasons t t jf), the activity increases linearly with the irradiation time. Advantage may be taken of this time dependence in the following ways If activation of short-lived radionuclides is required, whereas activation of long-lived radionuclides is not desired, short irradiation times are chosen and the samples are measured or used immediately after the end of irradiation. In the opposite case, long irradiation times are chosen and the sample is allowed to decay until the short-lived activity has become negligible. With increasing decay time, the activity ratios of the radionuclides that have been pro-... 

Application of short-lived radionuclides has the advantage that the activity vanishes after relatively short periods of time. This aspect is of special importance in nuclear medicine. Short-hved radionuclides may be produced by irradiation in nuclear reactors or by accelerators, but their supply from in-adiation facilities requires matching of production and demand, and fast transport. These problems are avoided by application of radionuclide generators containing a longer-lived mother nuclide from which the short-hved daughter nuclide can be separated. 

Abstract The history, theoretical fundamentals, and practical application of thermochromatography are briefly reviewed. The main advantages of the method - the speed and selectivity of chemical separation of complex mixtures of short-lived radionuclides, including transactinide ones - are analyzed. Prospects of thermochromatography in production of radionuclides widely used in science and technology are considered on the basis of the performed systematic investigations of the thermochromatographic behavior of volatile compounds of the elements of the periodic table. 

Both radiometric and mass spectrometric detection approaches have been used in automated radiochemical analysis, depending on the radionuclides of interest and the capabilities of the laboratory involved. The tradeoffs between radiation counting and atom counting have been described.14 16 17 Short-lived fission products may be advantageously detected with radiation detection, whereas long-lived (low specific activity) radionuclides can be determined with better sensitivity using ICP-MS. 

Another advantage of PET consists of the physiological aspects of most of the available positron-emitting radionuclides, which are usually of low atomic number. Among these radionuclides, C, N, O, and F are used most often in PET because of their physiological affinity in the human body and their short physical half-lives... 

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