Possibility of production of 67Cu at a small-sized cyclotron via the (p,α)-reaction on enriched 70Zn

The possibility of production of the therapy related β--emitting radioisotope 67Cu (T1/2 = 61.9 h, Eβ-(max) = 0.6 MeV) at a small-sized cyclotron via the 70Zn(p,α)67Cu reaction was investigated. The excitation function of the reaction was measured for the first time from threshold to 35 MeV using the stacked-foil technique. Thin samples were prepared by electrolytic deposition of 85% enriched 70Zn on Au-backing. The radiocopper produced in each irradiated sample was separated chemically by extraction methods, and the radioactivity was assayed by high-resolution γ-ray spectrometry. The integral yield of 67Cu was calculated from the measured cross section data. The energy range Ep = 18 → 8 appears to be optimum. With 85% enriched 70Zn the thick target yield of 67Cu amounts to about 2.0 MBq/μAh (182 MBq/μA at saturation) with low radionuclidic impurity (<10% 64Cu). A higher target enrichment would further reduce the impurity level. Using modern small-sized cyclotrons, it is possible to produce 67Cu in quantities sufficient for therapeutic applications. (orig.)