Ⅰ. HIGHLIGHTS OF THE YEARRIKEN Accel. Prog. Rep. 49 (2016)

Productionofof6767Cu
Cuusingusing thed,αn)6767
Cu
Production
the 7070Zn(Zn(d,αn)Cureaction
reaction
S. Yano,＊1 H. Haba,＊1 S. Shibata,＊1 Y. Komori,＊1 K. Takahashi,＊1 Y. Wakitani,＊2 T. Yamada,＊2 and M. Matsumoto＊2Since 2007, we have distributed purified radioisotopes
such as 65Zn and 109Cd prepared at the RIKEN AVF cyclotron
for the purpose of contribution to society throughout
industrial application of accelerator based- science.1) Copper67 (half-life T1/2 = 61.83 h and β–-decay branch Iβ- = 100%)is one of the promising radioisotopes for radiotherapy andradiodiagnosis.2) Although several routes have been
proposed for the production of 67Cu, the high-energy protoninduced reaction of 68Zn(p,2p)67Cu has been used mostoften.3) In this route, however, a large-scale cyclotron isrequired to accelerate protons up to ~ 100 MeV, and a large
contamination of the radionuclidic impurity of 64Cu is
unavoidable in the 67Cu product.3) Further, the long-lived
byproduct of 65Zn (T1/2 = 244.06 d) is also undesired in therecycle process of the enriched target material of 68Zn. Thus,
we plan to produce 67Cu in the 70Zn(d,αn)67Cu reaction,
where small amounts of 64Cu and 65Zn are produced.4) In thiswork, for the future distribution of 67Cu, we investigated aprocedure to prepare purified 67Cu in the 70Zn(d,αn)67Cu
reaction at the AVF cyclotron.
In the 70Zn(d,αn)67Cu route, 67Ga can be produced from Zn
isotopes such as 66Zn and 67Zn, which are contained in small
amounts in the enriched 70Zn target. The γ-ray energies of67
Ga are identical to those of 67Cu, because 67Ga and 67Cu
decay to the same excited levels of 67Zn by EC- and β–-decay,respectively. In addition, the half-life of 67Ga (T1/2 = 3.26 d)
is almost the same as that of 67Cu. Thus, it is difficult todistinguish between 67Cu and 67Ga by γ-ray spectrometry.
Also the expensive enriched isotope of 70Zn should berecovered for reuse. To develop a chemical procedure toremove 67Ga from 67Cu and to recover the rare 70Zn material,
we first produced radiotracers of 61Cu, 66Ga, and 69mZn in thenatZn(d,X) reactions by irradiating 24-MeV deuterons on ametallic natZn foil (nat: natural isotopic abundance; chemicalpurity: >99.99%; thickness: 71.4 mg cm–2). The average
beam intensity was 150 nA, and the irradiation time was 26min. An enriched 70ZnO target (70Zn isotopic abundance:96.87%; thickness: 327 mg cm–2) was also irradiated with the24-MeV deuterons in order to evaluate the production yieldof 67Cu from 70Zn and the quality of the purified 67Cu product.
The average beam intensity was 18 nA, and the irradiation
time was 56 min. After the irradiation, as shown in Fig. 1, Cu
isotopes were separated from the natZn and 70ZnO targets
through a two-step chromatographic separation using theEichrom Cu resin and the Dowex 1X8 anion-exchangeresin.5) We carried out the chemical procedure using theradiotracers of 61Cu, 66Ga, and 69mZn produced in thenatZn(d,X) reaction. A high chemical yield of 97% wasobtained for 61Cu. Decontamination factors of 66Ga and 69mZn＊1＊2

RIKEN Nishina CenterJapan Radioisotope Association- 22 -from 61Cu were evaluated to be~103 and >103,respectively.
The recovery of >99% for 69mZn, was high enough forrecycling of the 70Zn target material. Figure 2 shows the γray spectrum of the purified 67Cu from the enriched 70Zntarget. Under the present experimental condition, theproduction yield of 67Cu was 4.0 MBq μA–1h–1. The
radioactivity ratio of A(67Cu)/A(67Ga) was about 2×104 after
the chemical separation. Based on the present results, weestimate that about 1 GBq of 67Cu could be distributed after
3-days irradiation of a metallic 70Zn target of 357-mg cm–2
thickness with a 24-MeV and 10-μA deuteron beam,followed by 3 days for chemical separation and shipment.

Fig. 1. Chemical separation procedure for 67Cu produced inthe 70Zn(d,αn)67Cu reaction.

Fig. 2. γ-ray spectrum of the purified 67Cu from the enriched
Zn target irradiated with the 24-MeV deuteron.

70References

1) T. Kambara et al., RIKEN Accel. Prog. Rep. 42, 295 (2008).
2) I. Novak-Hofer et al., Eur. J. Nucl. Med. 29, 821 (2002).
3) IAEA Technical Reports Series 473 (2011).
4) J. Kozempel et al., Radiochim. Acta. 100, 419 (2012).
5) Eichrom technologies’ Product Catalog for 2013.