Presentation Co-precipitation method to separate 67Cu from a large amount of Zn target

Ohya, Tomoyuki  ,  Suzuki, Hisashi  ,  Fukada, Masami  ,  Nagatsu, Kotaro  ,  Minegishi, Katsuyuki  ,  Hanyu, Masayuki  ,  Ming-Rong, Zhang

2017-05-18
Description
ObjectivesCopper-67 is one of the most attractive radioisotopes applicable to ‘theranostic’ studies. Some methods using a combination of ion-exchange resins have been commonly used to separate radio-coppers including 67Cu from irradiated zinc target. However, it is mandatory to remove a relatively large amount of bulky zinc target and co-produced radionuclidic impurities. Our object is thus to develop a novel easy and speedy purification method of 67Cu from zinc. MethodsIn preliminarily experiments to develop our ‘co-precipitation’ method, we used a mimic target solution of 3.5 g of ZnO dissolved in 10M-HCl spiked with 64Cu solution. The solution was bubbled with H2S, then AgNO3 was added to co-precipitate copper ion with silver (1ppm). The solution was then passed through a cellulosic filter to trap 64CuS/Ag2S. Subsequently, acid cocktail (see below) was loaded into the filter to re-dissolve cupric ion. To enhance the separation quality, we repeated the above process again. The elution was then evaporated and reconstituted in UPW (64Cu final product). To evaluate and optimize the trapping/recovery rate of 64Cu, we changed the following parameters; volume of AgNO3, flow rate, and eluates. Considering above evaluation, we produced 67Cu via the reaction of 68Zn(p, 2p)67Cu. ResultsThe trapping rates of radio-copper on the filter were 83–97%, while it was about 30 % without silver addition. Considerable recoveries of trapped radio-Cu from the filter were accomplished under the following elute conditions; 2M-HCl+3M-HNO3 and HClO+4M-HCl (80–97%), though the recovery rate was strongly dependent on a flow rate of eluates. A pilot study of actual 67Cu production, we obtained 67Cu as the final product at a recovery rate of about 60% (decay-corrected). The concentrations of metallic impurities in the product were as follows (ppm): Cu: 0.02-0.03, Fe: 0.02-0.30, Zn 0.12-0.44, Ni, Co (N.D.). Radio activity of gallium (byproduct) was completely removed (N.D.).ConclusionsAlthough an evaluation of removing silver is underway, the co-precipitation method has a potential to prepare a high quality 67Cu from a bulk amount of Zn target.
22nd International symposium on radiopharmaceutical science (ISRS)ポスター発表に参加

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