NRC-8, EuCheMS International Conference on Nuclear and Radiochemistry

ORAL PRESENTATION - Development of ⁴⁴Sc production for radiopharmaceutical applications

17 Sept 2012, 16:40

15m

Como, Italy

Oral Communications Nuclear Chemistry, Radionuclide Production, High-Power Targetry Session 2 (cn't of Session 1) - Radiopharmaceutical Chemistry (radiodiagnostics, radiotherapy, theragnostics)

Speaker

Mrs Maruta Bunka (Laboratory of Radiochemistry and Environmental Chemistry, Villigen PSI, Switzerland)

Description

Introduction: 44Sc with a half-life of 3,97 h and a positron branching of 94 % is a promising nuclide for novel PET-radiopharmaceuticals. With an oxidation state of +3 44Sc may be used for radiolabeling of biomolecules with chelators established for coordination of lanthanides such as 177Lu and for other clinically employed radionuclides such as 90Y, 111In or 68Ga. At the Paul Scherrer Institute we are evaluating and optimizing the production of 44Sc for radiopharmaceutical applications. Methods: 44Sc was produced from a 44CaCO3 solid target at a cyclotron with protons up to 15 MeV (30-50 μA, 20-40 min). For the isolation of 44Sc from the target material extraction chromatography and cation exchange chromatography were employed. After the isolation and purification of 44Sc, radiolabeling reactions were investigated using different molar amounts of a DOTA-folate conjugate. Results: The irradiation yield was 150 – 200 MBq/μAh with < 1% of the co-produced longer-lived 44mSc (t1/2 = 2.44 d). The chemical separation and purification steps were achieved within 10-15 min providing 80-90 % of the total amount of produced radioactivity of 44Sc in a volume of 0.5 mL, suitable for direct radiolabeling reactions. Radiolabeling of a DOTA-folate resulted in yields up to 90 % . Conclusions: Rapid column-based chemical isolation of 44Sc from calcium targets and purification provides this novel PET isotope in a form suitable for labeling of biomolecules allowing the performance of in vitro studies. However, to achieve a higher specific activity concentration for in vivo studies further optimization of both, separation and labeling processes, are necessary.