Density reduction effects on the production of [11C]CO2 in Nb-body targets on a medical cyclotron

Lucas Mues Genannt Koers; David Prevost; Elisabeth Paulssen; Cornelia Hoehr

doi:10.1016/j.apradiso.2023.110911

Density reduction effects on the production of [11C]CO2 in Nb-body targets on a medical cyclotron

Appl Radiat Isot. 2023 Sep:199:110911. doi: 10.1016/j.apradiso.2023.110911. Epub 2023 Jun 22.

Authors

Lucas Mues Genannt Koers¹, David Prevost², Elisabeth Paulssen³, Cornelia Hoehr⁴

Affiliations

¹ Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada; Faculty of Chemistry and Biotechnology, FH Aachen, Heinrich-Mußmann-Str. 1, 52428, Jülich, Germany.
² Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada.
³ Faculty of Chemistry and Biotechnology, FH Aachen, Heinrich-Mußmann-Str. 1, 52428, Jülich, Germany; TU Delft, Department of Radiation Science and Technology, Mekelweg 15, 2629 JB, Delft, the Netherlands.
⁴ Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada. Electronic address: choehr@triumf.ca.

PMID: 37364423
DOI: 10.1016/j.apradiso.2023.110911

Abstract

Medical isotope production of ¹¹C is commonly performed in gaseous targets. The power deposition of the proton beam during the irradiation decreases the target density due to thermodynamic mixing and can cause an increase of penetration depth and divergence of the proton beam. In order to investigate the difference how the target-body length influences the operation conditions and the production yield, a 12 cm and a 22 cm Nb-target body containing N₂/O₂ gas were irradiated using a 13 MeV proton cyclotron. It was found that the density reduction has a large influence on the pressure rise during irradiation and the achievable radioactive yield. The saturation activity of [¹¹C]CO₂ for the long target (0.083 Ci/μA) is about 10% higher than in the short target geometry (0.075 Ci/μA).

Keywords: C-11; Carbon-11; Medical cyclotron; PET-Isotope.