Radiochemical separation and quality control of high specific activity Re-186g in no-carrier-added form from cyclotron irradiated W and W-186 targets

The 186gRe can be produced in carrier-added (CA) form by (n,y) reaction on enriched 185Re target in thermal nuclear reactor, with a lower specific activity AS than the theoretical carrier-free one (CF). Alternatively, it can be produced by either proton or deuteron irradiation on very highly enriched 186W target in no-carrier-added form (NCA), reaching a AS value very close to the CF one. The attention is focused on 186gRe due to its remarkable applications in for metabolic radiotherapy of tumors. A selective and efficient radiochemical separation of Re radionuclides was set up after irradiation of W metal target of natural isotopic composition. The separation was applied to enriched 186W powdered target too, with similar results. The separation was based on a radiochromatographic step, leading to a quantitative (99%) radiochemical yield for 186gRe and a high decontamination factor from W target, measured by 187W, obtained by 186W(n,y) activation.