Cyclotron production of PET radionuclides: 18F (109.77 min; β+ 96.9%; EC 3.1%) from high-energy protons on natural magnesium targets

The production of no-carrier-added (NCA) 18F (109.77 min) from proton induced reactions on Mg targets of natural isotopic composition was investigated in the 67.5-13.7-MeV energy range. In Mg targets, 22Na (2.602 a) and 24Na (15.04 h) were detected as radionuclide impurities. In 0-containing targets [i.e. Mg(OH)2], 7Be was also detected and measured. The total cross section (mbarn) for the production of 18F and single and cumulative yields (mCi/μAh) for the production of 18F, 22Na, 24Na and 7Be were measured and are reported here. The total cross section for 18F reached a peak value of 22.8±0.2 mbarn in the 60-70-MeV energy region. In the full energy range covered in this work, the cumulative 18F yield (67.5-13.7 MeV) was measured as 27.0±2.7 mCVi/μAh. However, for practical reasons, only a 18F yield of 24.9±2.5 mCi/μAh in the 67.6-40-MeV energy range needs consideration. Based upon these results, targetry aspects and the potential for the large-scale 18F production from Mg targets are discussed. These results are also compared to a previously reported study of the potential of Al targets for producing 18F with high-energy protons. (author)