Cross-section measurement of the 169Tm(p,n) reaction for the production of the therapeutic radionuclide 169Yb and comparison with its reactor-based generation

The radionuclide 169Yb (T1/2=32.0d) is potentially important for internal radiotherapy. It is generally produced using a nuclear reactor. In this work the possibility of its production at a cyclotron was investigated. A detailed determination of the excitation function of the 169Tm(p,n)169Yb reaction was done over the proton energy range up to 45 MeV using the stacked-foil technique and high-resolution γ-ray spectrometry. The integral yield of 169Yb was calculated. Over the optimum energy range EP=16→7MeV the yield amounts to 1.5 MBq/μA h and is thus rather low. A comparison of this production route with the established 168Yb(n,γ)169Yb reaction at a nuclear reactor is given. The 169Yb yield via the reactor route is by several orders of magnitude higher than by the cyclotron method. The latter procedure, however, leads to “no-carrier-added” product.