Polymeric micelles are increasingly used in chemotherapy. To get a greater understanding of the behaviour of these micelles is important. Nuclear imaging, such as SPECT and PET can provide relevant information about the behaviour of the micelles. However, to use these techniques, the micelles must be radiolabelled. In this thesis a chelator free method will be described to radiolabel micelles. The goal of this thesis is to radiolabel block copolymers with Zr-89. For this purpose series of experiments were carried out. In these experiments three different concentrations ZrCl4 are applied, C1 = 0.04mM, C2 = 0.07mM and C3 = 1mM. These experiments are conducted for two different types of polymer micelles, PCL-PEO 2800-2000 and PLA-PEO 10500-5000. With these polymers, micelles are prepared, which are used for the radiolabeling process. The fractions obtained by the SEC (size exclusion chromatography) were analysed and the data was processed. At the first concentration C1 = 0.04mM, PCL-PEO 2800-2000 had an efficiency of 37,65 ± 2,48 %. PLA-PEO 10500-5000 gave a radiolabeling efficiency of 28,27 ± 1,23 %. The second concentration, C2 = 0.07mM, showed a decrease in radiolabeling efficiency. For the PCL-PEO-2800-2000 polymeric micelles a radiolabeling efficiency of 23,30 ± 13,94 % was found and for the PLA-PEO 10500-5000 micelles an efficiency of 19,76 ± 1,70 was found. Lastly at the third concentration, C3 = 1mM, for PCL-PEO 2800-2000 the radiolabeling efficiency was found to be 0,88 ± 0,07 %. The PLA-PEO 10500-5000 micelles gave back 2,91 ± 1,68 % as radiolabeling efficiency. A stablity test was performed at C1 = 0.04mM. The PCL-PEO 2800-2000 polymeric micelles had a retention ratio of 37,57 ± 4,35 %. The PLA-PEO 10500-5000 performed better, 69,03 ± 1,27 % of the zirconium was still found to be in the micelles after being challenged by diethylenetriaminepentaacetic acid, or in short, DTPA. A stability test was also performed at C3 = 1mM, but results were found that are not usable. This experiment should be done again in future research.

The recently discovered negative health effects of Gd(III) complexes based magnetic resonance imaging (MRI) contrast agents have stirred interest into the development of alternatives based on Mn(II) complexes
due to its biocompatibility, and hence less health concerns. One important aspect of investigation on contrast agents in general, and Mn(II) complexes in particular, is an accurate determination of their concentrations in solution. Therefore, in this study a known approach of determining the concentration of paramagnetic species in solution, via the Bulk Magnetic Susceptibility (BMS) shift, is applied for Mn(II) and the feasibility of the method is evaluated. A proof of principle using Gd-DOTP concentrations in the range 0.7 – 6.6 mM Gd(III) to verify the applied BMS method was successfully performed. Subsequently, BMS measurements were performed with MnDOTA as well as free Mn(II) and the obtained concentrations were verified with ICP-OES. A good agreement between the two methods was found within the concentration range of 0.4 - 15.1 mM Mn(II) for both MnDOTA and free Mn(II). Although, BMS measurements showed slightly higher concentrations than those found by ICP-OES for both Mn-DOTA and free Mn(II). Additionally, the deviations between ICP-OES and BMS were greater for free Mn(II) compared to Mn-DOTA. Experiments for determining the accuracy of the BMS method showed a 2.5% upward systematic error. The random error decreased from 20% for 0.27 mM Mn(II) to almost 0% for 4.0 mM Mn(II) and higher concentrations. In conclusion, the BMS method proved to be accurate for determining Mn(II) concentrations and has
promising prospects for future research into Mn(II) complexes. However, deviations between ICP-OES and BMS measurements need further investigations. Key words: Bulk Magnetic Susceptibility shift, contrast agent, Mn(II) complexes.