Separation of 44mSc/44gSc Nuclear Isomers Based on After-Effects

Elena Sergeevna Kurakina; Luke Wharton; Jurabek Khushvaktov; Eldar Parpachevich Magomedbekov; Valery Radchenko; Dmitry Filosofov

doi:10.1021/acs.inorgchem.3c01495

Separation of ^44mSc/^44gSc Nuclear Isomers Based on After-Effects

Inorg Chem. 2023 Dec 18;62(50):20646-20654. doi: 10.1021/acs.inorgchem.3c01495. Epub 2023 Aug 25.

Authors

Elena Sergeevna Kurakina^{1

2}, Luke Wharton³, Jurabek Khushvaktov¹, Eldar Parpachevich Magomedbekov², Valery Radchenko³, Dmitry Filosofov¹

Affiliations

¹ Dzhelepov Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, Dubna 141980, Russian Federation.
² Department of High-Energy Chemistry and Radioecology, D. Mendeleev University of Chemical Technology of Russia, Moscow 125047, Russian Federation.
³ Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.

PMID: 37625137
DOI: 10.1021/acs.inorgchem.3c01495

Abstract

^44gSc presents a particular interest for application in nuclear medicine for positron emission tomography (PET) due to its favorable nuclear decay properties (t_1/2 = 3.97 h, E_max = 1.47 MeV, branching ratio 94.3% β⁺). Its nuclear isomer ^44mSc (t_1/2 = 58.61 h) decays by isomeric transition (IT) into ^44gSc, accompanied by ≈12% of conversion electron emission, which can cause a partial release of the daughter ^44gSc from the chelate complex. A 13 MeV cyclotron at TRIUMF was used to produce both ^44mSc and ^44gSc via the ^natCa(p,n)^44m,gSc reaction. A ^44mSc/^44gSc generator was designed by using a Strata C-18E cartridge. After several tested systems, a successful separation method was developed using DOTATOC as a chelator, a Strata C-18E cartridge as a generator column, and an elution solution of 0.1 M NH₄-α-HIB. The yield of the generator with the daughter ^44gSc release was equal to 9.8 ± 1.0% (or ≈80% per portion of conversion). This result shows the important role of after-effects in the design of radionuclide generators. Nuclear cross-section calculations were applied using the TALYS code to allow for the determination of the most promising alternative routes for ^44mSc production, which will enable the development of a full-scale ^44mSc/^44gSc radionuclide generator based on after-effects.