New Production Routes for Medical Isotopes 64Cu and 67Cu Using Accelerator Neutrons

We have measured the activation cross sections producing Cu-64 and Cu-67, promising medical radioisotopes for molecular imaging and radioimmunotherapy, by bombarding a natural zinc sample with 14MeV neutrons. We estimated the production yields of Cu-64 and Cu-67 by fast neutrons from C-nat(d,n) with 40 MeV 5 mA deuterons. We used the present result together with the evaluated cross section of Zn isotopes. The calculated Cu-64 yield is 1.8 TBq (175 g Zn-64) for 12 h of irradiation; the yields of Cu-67 by Zn-67(n,p) Cu-67 and Zn-68(n,x)Cu-67 were 249 GBq (184 g Zn-67) and 287 GBq (186 g Zn-68) at the end of 2 days of irradiation, respectively. From the results, we proposed a new route to produce 67Cu with very little radionuclide impurity via the Zn-68(n,x) Cu-67 reaction, and showed the Zn-64(n,p)Cu-64 reaction to be a promising route to produce Cu-64. Both Cu-67 and Cu-64 are noted to be produced using fast neutrons.