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 181-186gRe 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 186gRe was also studied by the irradiation of thick-target of enriched 186W with a 13.6±0.2 MeV proton beam. The results for 186W(p, n)186gRe were compared also to those calculated by the EMPIRE II code (version 2.19), due to 186gRe extensive applications in nuclear medicine for metabolic radiotherapy of tumours. It was found that the maximum percentage of 186gRe by irradiation of natural tungsten is about 20% only, which confirms the conclusion that high radionuclidic purity and specific activity of 186gRe necessitate the use of highly enriched 186W target. (orig.)