Excitation functions and yields for cyclotron production of radiorhenium via natW(p, xn)181-186gRe nuclear reactions and tests on the production of 186gRe using enriched 186W

Excitation functions and thin-target yields for the Re181-186g radionuclides have been measured by the stacked-foil activation technique on tungsten foils of natural isotopic composition for different proton energies up to 22.0 MeV. A further check on the cross sections was done by irradiation of thick-targets and comparing the irradiated thick-target yields with those calculated by analytical integration from the thin-target yields. The production of Re-186g was also studied by the irradiation of thick-target of enriched W-186 with a 13.6 +/- 0.2 MeV proton beam. The results for W-186(p, n)Re-186g were compared also to those calculated by the EMPIRE II code (version 2.19), due to Re-186g extensive applications in nuclear medicine for metabolic radiotherapy of tumours. It was found that the maximum percentage of Re-186g by irradiation of natural tungsten is about 20% only, which confirms the conclusion that high radionuclidic purity and specific activity of Re-186g necessitate the use of highly enriched W-186 target.