Improved procedures of Sc(OH)3 precipitation and UTEVA extraction for 44Sc separation.

BACKGROUND: 44Sc is becoming attractive as a PET radionuclide due to its decay characteristics. It can be produced from 44Ca present in natural calcium with 2.08% abundance. MATERIALS AND METHODS: The targets were mostly prepared from natural CaCO3 or metallic calcium in the form of pellets. After irradiation they were dissolved in 3 M hydrochloric acid and 44Sc was separated from excess of calcium by precipitation of scandium hydroxide using ammonia. Alternatively, targets were dissolved in 11 M hydrochloric acid and 44Sc was separated by extraction chromatography on UTEVA resin. As the next step, in both processes 44Sc was further purified on a cation exchange resin. Initially, the separation procedures were developed with 46Sc as a tracer. Gamma spectrometry with a high purity germanium detector was used to determine the separation efficiency. Finally, the CaCO3 pellet with 99.2% enrichment in 44Ca was activated with protons via 44Ca(p,n)44Sc nuclear reaction. RESULTS: Altogether twenty two irradiations and separations were performed. The working procedures were developed and the quality of separated 44Sc solution was confirmed by radiolabeling of DOTATATE. The chemical purity of the product was sufficient for preclinical experiments. At the end of around 1 hour proton beam irradiation of CaCO3 pellet with 99.2% enrichment in 44Ca the obtained radioactivity of 44Sc was more than 4.8 GBq. CONCLUSION: 44Sc can be produced inexpensively with adequate yields and radionuclidic purity via 44Ca(p,n)44Sc nuclear reaction in small cyclotrons. The recovery yield in both investigated separation methods was comparable and amounted above 90%. The obtained 44Sc was pure in terms of radionuclide and chemical purity, as shown by the results of peptide radiolabeling.

Thermal diffusion of 57Co into rhodium matrix as a second step in preparing Mössbauer sources.

Thermal diffusion of (57)Co into rhodium matrix was studied. The diffusion degree was evaluated by Mössbauer spectroscopy with the use of α-Fe absorber. The influence of different annealing conditions was investigated. For a set of sources examined, smooth and rounded Lorentzian lines were observed. The main spectra parameters are fairly acceptable with respect to the typical obtainable values for α-Fe absorbers in Mössbauer spectroscopy. The results obtained confirm that the deposited (57)Co diffused almost completely into rhodium matrix without substantial loss of the activity deposited.

Electrodeposition of carrier-free 57Co on rhodium as an approach to the preparation of Mössbauer sources.

Electrodeposition of carrier-free (57)Co on a rhodium matrix as the first step of preparing Mössbauer sources was studied. To optimize the plating parameters, the influences of current density, volume and pH of the electrolyte solution, shape, thickness, and surface area of the rhodium cathode, mode of cathode pretreatment, concentration of (57)Co and duration of electrolysis were investigated.