title: Cyclotron production of (43)Sc for PET imaging.
abstract: BACKGROUND
  Recently, significant interest in (44)Sc as a tracer for positron emission tomography (PET) imaging has been observed. Unfortunately, the co-emission by (44)Sc of high-energy γ rays (E γ = 1157, 1499 keV) causes a dangerous increase of the radiation dose to the patients and clinical staff. However, it is possible to produce another radionuclide of scandium-(43)Sc-having properties similar to (44)Sc but is characterized by much lower energy of the concurrent gamma emissions. This work presents the production route of (43)Sc by α irradiation of natural calcium, its separation and purification processes, and the labeling of [DOTA,Tyr3] octreotate (DOTATATE) bioconjugate.
  
  
  METHODS
  Natural CaCO3 and enriched [(40)Ca]CaCO3 were irradiated with alpha particles for 1 h in an energy range of 14.8-30 MeV at a beam current of 0.5 or 0.25 μA. In order to find the optimum method for the separation of (43)Sc from irradiated calcium targets, three processes previously developed for (44)Sc were tested. Radiolabeling experiments were performed with DOTATATE radiobioconjugate, and the stability of the obtained (43)Sc-DOTATATE was tested in human serum.
  
  
  RESULTS
  Studies of (nat)CaCO3 target irradiation by alpha particles show that the optimum alpha particle energies are in the range of 24-27 MeV, giving 102 MBq/μA/h of (43)Sc radioactivity which creates the opportunity to produce several GBq of (43)Sc. The separation experiments performed indicate that, as with (44)Sc, due to the simplicity of the operations and because of the chemical purity of the (43)Sc obtained, the best separation process is when UTEVA resin is used. The DOTATATE conjugate was labeled by the obtained (43)Sc with a yield >98 % at elevated temperature.
  
  
  CONCLUSIONS
  Tens of GBq activities of (43)Sc of high radionuclidic purity can be obtainable for clinical applications by irradiation of natural calcium with an alpha beam.
authors.affiliation: Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195, Warsaw, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Walczak
authors.affiliation: Synektik S.A., Research and Development Center, Warsaw, Poland.
authors.forename: Seweryn
authors.initials: S
authors.lastname: Krajewski
authors.affiliation: Department of Nuclear Physics, University of Silesia, Katowice, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Szkliniarz
authors.affiliation: Heavy Ion Laboratory, University of Warsaw, Warsaw, Poland.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Sitarz
authors.affiliation: Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements, European Commission, Ispra, Italy.
authors.forename: Kamel
authors.initials: K
authors.lastname: Abbas
authors.affiliation: Heavy Ion Laboratory, University of Warsaw, Warsaw, Poland.
authors.forename: Jarosław
authors.initials: J
authors.lastname: Choiński
authors.affiliation: Heavy Ion Laboratory, University of Warsaw, Warsaw, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Jakubowski
authors.affiliation: Heavy Ion Laboratory, University of Warsaw, Warsaw, Poland.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Jastrzębski
authors.affiliation: Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195, Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Majkowska
authors.affiliation: Nuclear Decommissioning Unit, Joint Research Centre, Ispra Site Management Directorate, European Commission, Ispra, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Simonelli
authors.affiliation: Heavy Ion Laboratory, University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Stolarz
authors.affiliation: Heavy Ion Laboratory, University of Warsaw, Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Trzcińska
authors.affiliation: Department of Nuclear Physics, University of Silesia, Katowice, Poland.
authors.forename: Wiktor
authors.initials: W
authors.lastname: Zipper
authors.affiliation: Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195, Warsaw, Poland. a.bilewicz@ichtj.waw.pl.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Bilewicz
keywords: Alpha irradiation; Calcium target; Cyclotron production; PET radiopharmaceuticals; Scandium-43