Cyclotron-Based Production of 67Cu for Radionuclide Theranostics via the 70Zn(p,α)67Cu Reaction

Abstract

Theranostic matched pairs of radionuclides have aroused interest during the last couple of years, and in that sense, copper is one element that has a lot to offer, and although 61Cu and 64Cu are slowly being established as diagnostic radionuclides for PET, the availability of the therapeutic counterpart 67Cu plays a key role for further radiopharmaceutical development in the future. Until now, the 67Cu shortage has not been solved; however, different production routes are being explored. This project aims at the production of no-carrier-added 67Cu with high radionuclidic purity with a medical 30MeV compact cyclotron via the 70Zn(p,α)67Cu reaction. With this purpose, proton irradiation of electrodeposited 70Zn targets was performed followed by two-step radiochemical separation based on solid-phase extraction. Activities of up to 600MBq 67Cu at end of bombardment, with radionuclidic purities over 99.5% and apparent molar activities of up to 80MBq/nmol, were quantified.

Production of Medical Radionuclides in the Center for Radiopharmaceutical Tumor Research—A Status Report

“…A saturation yield of approximately 3.2 GBq/µA for a 70 mg 68 Zn target has been quantified, leading to activities of up to 2 GBq at EOB for a 2 h proton irradiation. This yield accounts for about 70% of the theoretical one calculated, which corresponds with the results obtained for other radionuclides produced at our cyclotron [21,27,28].…”

“…Work-up of the target is performed 8 to 16 h after EOB to reduce the activity of short-lived radionuclides, e.g., 68 Ga. Radiochemical purification is based on a three-step chromatographic separation; First, a 1 mL CU resin is used for the bulk target separation, followed by a 1 mL TK400 resin for 66/67 Ga retention, where the radiocopper runs through the column with 8 M HCl. The last step involves a 1 mL TK201 resin, where 70 Zn traces are retained and a ready-to-label [ 67 Cu]CuCl 2 fraction is obtained, accounting for roughly 85% of the activity of the raw solution (decay-corrected) [21].…”

“…Target irradiation is performed with 19 MeV protons at a 35 µA current using the 30 • solid-state target configuration. These optimized parameters are calculated analogously to the ones for 67 Cu production [21]. Target production follows the method described for 67 Cu targets, but replaces the enriched 70 Zn with enriched 68 Zn.…”

Highlight selection of radiochemistry and radiopharmacy developments by editorial board

“…A recent publication of the Helmholtz-Zentrum Dresden-Rossendorf group reports on their experience producing 67 Cu, a promising beta-emitter for targeted radionuclide therapy, via the 70 Zn(p,α) 67 Cu reaction (Brühlmann et al 2023 ). Thick depositions (> 100 mg/cm 2 ) of isotopically enriched 70 Zn (> 97%) were efficiently electroplated on gold and silver substrates and irradiated with currents over 50 µA of 17 MeV protons, for up to 12 h, obtaining 67 Cu with high radionuclide purity (> 99.5%) and apparent molar activity (80 MBq/nmol), in a yield close to the GBq range, and real possibilities of improvement.…”

First Results on Zinc Oxide Thick Film Deposition by Inverted Magnetron Sputtering for Cyclotron Solid Targets Production

“…The potential of the MS technique implemented in this work can be exploited to expand the number of radionuclides available for diagnostics , , , , and for the therapy. With this regard, it is important to emphasise the versatility of the theranostic (therapy + diagnostics) radionuclide , under the spotlight of the scientific community [ 16 , 17 , 18 ]. Although the nuclear physics reactions to optimise the production have been extensively studied [ 17 ], its production in a sufficient amount for pre-clinical as well as clinical tests is limited by the lack of a suitable target that can withstand the high proton beam current.…”