This title appears in the Scientific Report :
2015
Please use the identifier:
http://hdl.handle.net/2128/8992 in citations.
Investigations on the production of $^{52g}$Mn and $^{147,149}$Gd for authentic labelling of MR contrast agents
Investigations on the production of $^{52g}$Mn and $^{147,149}$Gd for authentic labelling of MR contrast agents
Addressing the quantitation problem of contrast enhancing MRI compounds based ongadolinium (III) and manganese (II), the production of suitable radionuclides as well asactivation and the authentic radiolabelling of MR contrast agents were examined.The existing cross section data of the $^{nat}$Eu(d,...
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Personal Name(s): | Buchholz, Martin (Corresponding author) |
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Contributing Institute: |
Nuklearchemie; INM-5 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2015
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Physical Description: |
XI, 126 p. |
Document Type: |
Report Book |
Research Program: |
Neuroimaging |
Series Title: |
Berichte des Forschungszentrums Jülich
4387 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Addressing the quantitation problem of contrast enhancing MRI compounds based ongadolinium (III) and manganese (II), the production of suitable radionuclides as well asactivation and the authentic radiolabelling of MR contrast agents were examined.The existing cross section data of the $^{nat}$Eu(d,x)$^{147,149}$Gd and $^{nat}$Eu(p,x)$^{147,149}$Gd reactions were expanded up to 70.9 MeV and 44.8 MeV, respectively. The integral production rates of the $^{nat}$Eu(d,x)$^{147}$Gd and $^{nat}$Eu(p,x)$^{147}$Gd reactions were 177.3 ± 19.7 and 43.3 ± 4.4 MBq/$\mu$Ah while the integral production rates of the $^{nat}$Eu(d,x)$^{149}$Gd and $^{nat}$Eu(p,x)$^{149}$Gd reactions amounted to 81.6 ± 8.5 and 61.8 ± 4.9 MBq/$\mu$Ah, respectively. The formation of longer-lived radioisotopic impurities ($^{146,151,153}$Gd) was below 7 %, but the use of enriched Eu target material was found to be necessary for a radionuclidically pure production of either $^{147}$Gd or $^{149}$Gd. Since the production rates are higher than for the earlier proposed irradiation of highly enriched $^{144,147}$Sm with $\alpha$- or $^{3}$He-particles, Eu is an interesting alternative for the production of $^{147,149}$Gd. In addition to the measurement of nuclear data, a new radiochemical separation of the bulk target material Eu and n.c.a. *Gd based on an extraction of Eu into Na-Hg amalgam was successfully developed. In a proof of principle synthesis, the obtained *Gd was complexed with the ligand DOTA and an adequate stability of the complex confirmed over 6 d in Human Blood Serum (HBS). In a comparison by $\textit{in}$ and $\textit{ex vivo}$ MR and autoradiographic measurements of the commercial Gd-DOTA complex, DOTArem$^{TM}$, and the synthesised radioactive complex on tumour bearing rats a rather similar accumulation in the tumour tissue and surrounding striatum was found. Furthermore, production yields of the proton induced nuclear reactions on $^{nat}$Cr leading to $^{52g}$Mn, $^{52m}$Mn and $^{51}$Cr were measured in the energy range from 8.2 to 16.9 MeV and saturation thick target yields calculated as 2.6 ± 0.3, 7.0 ± 0.6 and 1.5 ± 0.2 GBq/$\mu$A, respectively. A new chromatographic separation method was developed which yielded 99.5 % of pure $^{52g}$Mn in 2 mL of 3M hydrochloric acid solution. Thereby, n.c.a. $^{52g}$Mn can be provided more efficiently for the isotopic labelling of MR contrast agents. The radioactive nanoparticle precursor Mn(acac)$_{2}$ was synthesised with a radiochemical yield of 73.9 ± 5.0 %. Additionally, activation studies with protons and neutrons were performed with commercially available water-dispersible Mn$_{3}$O$_{4}$ nanoparticles. The activated nanoparticles were characterised with DLS and TEM. No change between the initial and irradiated nanoparticleswas found with neutron activation. A broader size distribution and the scattered appearance of bigger crystals were observed in the proton irradiated samples caused by partial melting and recrystallization of the samples during irradiation. Leaching experiments of the neutron activated particles in H$_{2}$O and PBS resulted in 0.033 ± 0.005 % of released Mn after a 15 h incubation time indicating a high stability of the compound. |