Cyclotron production of high purity (44m,44)Sc with deuterons from (44)CaCO3 targets

C Alliot; R Kerdjoudj; N Michel; F Haddad; S Huclier-Markai

doi:10.1016/j.nucmedbio.2015.03.002

Cyclotron production of high purity (44m,44)Sc with deuterons from (44)CaCO3 targets

Nucl Med Biol. 2015 Jun;42(6):524-9. doi: 10.1016/j.nucmedbio.2015.03.002. Epub 2015 Mar 11.

Authors

C Alliot¹, R Kerdjoudj², N Michel³, F Haddad³, S Huclier-Markai³

Affiliations

¹ GIP Arronax, 1 rue Arronax, BP 10112, 44817 Saint-Herblain, France; Inserm U892, Centre de Recherche en Cancérologie Nantes - Angers, Institut de Biologie, 9 quai Moncousu, 44035 Nantes cedex 01, France. Electronic address: alliot@arronax-nantes.fr.
² Subatech Laboratory, UMR 6457, Ecole des Mines de Nantes, IN2P3/CNRS, Université de Nantes, 4 rue Alfred Kastler, 44300 Nantes, France.
³ GIP Arronax, 1 rue Arronax, BP 10112, 44817 Saint-Herblain, France; Subatech Laboratory, UMR 6457, Ecole des Mines de Nantes, IN2P3/CNRS, Université de Nantes, 4 rue Alfred Kastler, 44300 Nantes, France.

PMID: 25794463
DOI: 10.1016/j.nucmedbio.2015.03.002

Abstract

Introduction: Due to its longer half-life, (44)Sc (T1/2 = 3.97 h) as a positron emitter can be an interesting alternative to (68)Ga (T1/2 = 67.71 min). It has been already proposed as a PET radionuclide for scouting bone disease and is already available as a (44)Ti/(44)Sc generator. (44)Sc has an isomeric state, (44 m)Sc (T1/2 = 58.6 h), which can be co-produced with (44)Sc and that has been proved to be considered as an in-vivo PET generator (44 m)Sc/(44)Sc. This work presents the production route of (44 m)Sc/(44)Sc generator from (44)Ca(d,2n), its extraction/purification process and the evaluation of its performances.

Methods: Irradiation was performed in a low activity target station using a deuteron beam of 16 MeV, which favors the number of (44 m)Sc atoms produced simultaneously to (44)Sc. Typical irradiation conditions were 60 min at 0.2 μA producing 44 MBq of (44)Sc with a (44)Sc/(44 m)Sc activity ratio of 50 at end of irradiation. Separations of the radionuclides were performed by means of cation exchange chromatography using a DGA® resin (Triskem). Then, the developed process was applied with bigger targets, and could be used for preclinical studies.

Results: The extraction/purification process leads to a radionucleidic purity higher than 99.99% ((43)Sc, (46)Sc, (48)Sc < DL). (44 m)Sc/(44)Sc labeling towards DOTA moiety was performed in order to get an evaluation of the specific activities that could be reached with regard to all metallic impurities from the resulting source. Reaction parameters of radiolabeling were optimized, reaching yields over 95%, and leading to a specific activity of about 10-20 MBq/nmol for DOTA. A recycling process for the enriched (44)Ca target was developed and optimized.

Conclusion: The quality of the final batch with regard to radionucleidic purity, specific activity and metal impurities allowed a right away use for further radiopharmaceutical evaluation. This radionucleidic pair of (44 m)Sc/(44)Sc offers a quite interesting PET radionuclide for being further evaluated as an in-vivo generator.

Keywords: (44m)Sc/(44)Sc; In-vivo generator; Isotope production; Purification process.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Calcium Carbonate / chemistry*
Chelating Agents / chemistry
Cyclotrons*
Deuterium / chemistry*
Heterocyclic Compounds, 1-Ring / chemistry*
Isotope Labeling
Positron-Emission Tomography*
Radiopharmaceuticals / chemistry*
Scandium / chemistry*

Substances

Chelating Agents
Heterocyclic Compounds, 1-Ring
Radiopharmaceuticals
1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid
Deuterium
Calcium Carbonate
Scandium