RESUMO
INTRODUCTION: Four terbium isotopes 149,152,155,161Tb emitting various types of radiation can be used for both diagnostics and therapy. 152Tb emits positrons and is ideal for PET. 155Tb is considered a promising Auger emitter and a diagnostic pair for other terbium therapeutic isotopes. Several methods for the production of 155Tb using charged particle accelerators have been proposed, but they all have significant limitations. The restricted availability of this isotope hinders its medical applications. We have proposed a new method for production of 155Tb, irradiating enriched 155Gd by alpha particles. The possibility of simultaneous production of two isotopes of terbium, 152,155Tb, was also studied for more efficient cyclotron beam use. METHODS: Irradiation of 155Gd enriched targets and 155Gdâ¯/â¯151Eu tandem target with alpha-particles with an energy of 54â¯MeV was carried out at the U-150 cyclotron at the NRC "Kurchatov Institute". The cross sections of nuclear reactions on enr-155Gd were measured by the stack foil technique, detecting the gamma-radiation of the activation products. The separation of rare earth elements was performed by extraction chromatography with the LN Resin. 155Tb was produced via 155Dy decay. RESULTS: The cross sections for the 155,156Tb and 155,157Dy production were measured by the irradiation of a gadolinium target enriched with the 155Gd isotope with alpha-particles in an energy range of 54â¯ââ¯33â¯MeV. The yield of 155Dy on a thick target at 54â¯MeV was 130â¯MBq/µAh, which makes it possible to obtain 1â¯GBq of 155Tb in 11â¯hour-irradiation with 20⯵A beam current. The possibility of simultaneous production of 152,155Tb by irradiation of 155Gd and 151Eu tandem target with medium-energy alpha-particles is implemented. Optimal irradiation energy ranges of alpha -particles as 54â¯ââ¯42â¯MeV for 155Tb and 42â¯ââ¯34â¯MeV for 152Tb were suggested. Product activity and radionuclidic purity were calculated.
Assuntos
Partículas alfa , Térbio , Térbio/química , Partículas alfa/uso terapêutico , Radioisótopos/química , ElétronsRESUMO
Irradiation of 186W targets by 3He particles was carried out. For the first time the cross sections for the reactions of production of 183, 184, 186, 188Re, 183, 185Os, 187W were measured by the stack foil technique in the 3He energy range of 15-45 MeV. The results were compared to the data from the TENDL-2019 library. Using the experimental excitation functions, the thick target yields of medically relevant rhenium radioisotopes were calculated.