This title appears in the Scientific Report :
2015
Please use the identifier:
http://hdl.handle.net/2128/8576 in citations.
Untersuchungen zur Produktion und Anwendung von trägerarmem Radioselen für Markierungssynthesen
Untersuchungen zur Produktion und Anwendung von trägerarmem Radioselen für Markierungssynthesen
The positron emitter $^{73}$Se(T$_{1/2}$ = 7.15h, l$^{+}_{\beta}$ = 65 %, E$^{+}_{\beta}$ = 1.3 MeV) is a suitable radionuclide for PET studies. As a higher homolog to sulphur it is very interesting for analog labelling of sulphur-compounds and also for authentic labelling of drugs like Ebselen for...
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Personal Name(s): | Wels, Tobias (Corresponding Author) |
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Contributing Institute: |
Nuklearchemie; INM-5 |
Published in: | 2015 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2015
|
Physical Description: |
90 p. |
Document Type: |
Report Book |
Research Program: |
ohne Topic |
Series Title: |
Berichte des Forschungszentrums Jülich
4386 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
The positron emitter $^{73}$Se(T$_{1/2}$ = 7.15h, l$^{+}_{\beta}$ = 65 %, E$^{+}_{\beta}$ = 1.3 MeV) is a suitable radionuclide for PET studies. As a higher homolog to sulphur it is very interesting for analog labelling of sulphur-compounds and also for authentic labelling of drugs like Ebselen for $\textit{in vivo}$ use. The reaction cross sections for the production of $^{73}$Se and its isotopic by-product $^{75}$Se by the $^{75}$As(p,3n)$^{73}$Se and $^{75}$As(p,n)$^{75}$Se nuclear reacations were remeasured and extended to strengthen the available data. The reaction cross sections of the $^{75}$Se formation at E$_{p}$=41$\rightarrow$25.5 MeV was determined and amounted from 17 $\pm$ 0.2 to 31 $\pm$ 1.9 mbam, leading to a lower isotopic impurity than so far assumed. The maximum cross section of 285 $\pm$ 15 mbam for $^{73}$Se production by the $^{75}$As(p,3n)-reaction was found at 35 $\pm$ 0.2 ;eV. The cross section data of the $^{75}$As(p,pn)$^{74}$As nuclear reaction in the energy range above E$_{p}$=30 MeV was investigated for the first time and amounted from 131 $\pm$14 to 263 $\pm$ 15 mbam. This allows a first estimation for the formation of $^{74}$As in the energy range of 40 $\rightarrow$ 30 MeV. In order to isolate n.c.a. radioselenium from the proton-irradiated Cu$_{3}$As-target, a ionchromatographic method was optimized by determination of mass distribution coefficients and separation factors, using the longer lived $^{75}$Se (T$_{1/2}$ = 119,7 d, 100 % EC). By this procedure a radiochemical yield of 91 $\pm$ 2 % of n.c.a. radiosselenium was achieved. For the speciation of the n.c.a. radioselenium a ionchromatographic method was developed, which showed that the final product was abtained in form of pure selenite. For further labelling with n.c.a. radioselenium, the reduction of the selenium species to Se$^{0}$ was realized by using hydrazine to investigate the dependence between the reducing agent and the extraction behavior of the n.c.a. radioselenium. Hereby, the formation of an extractable sulfur-containing intermediate appears to be essential. For the transfer of n.c.a. $^{75}$Se into benzene with a radiochemical yield of ca 92 %, however, a 6 h extraction was necessary. With the example of the synthesis of n.c.a. [$^{75}$Se]Ebselen, leading to a total radiochemical yield of 18 to 29 %, the suitability of the benzolic radioselenium solution for radiosynthesis, obtained by the way described, could be demonstrated. |