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 thicktarget 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.