Production of the therapeutic radionuclides 193mPt and 195mPt with high specific activity via α-particle-induced reactions on 192Os

For the production of therapy-relevant radionuclides 193mPt (T1/2=4.33 d) and 195mPt (T1/2=4.03 d) with a high specific activity, the 192Os(α,n)195mPt and 192Os(α,3n)193mPt nuclear reactions were investigated for the first time from their respective thresholds up to 28 MeV. Thin samples of enriched 192Os were prepared by electrodeposition on Ni, and the conventional stacked-foil technique was used for cross-section measurements. The calculated thick target yields were found to be 0.013 MBq/μA h for the 192Os(α,n)195mPt reaction in the energy range of Eα=24→18 MeV, and 0.25 MBq/μA h for the 192Os(α,3n)193mPt reaction in the energy range of Eα=28→24 MeV. The two radionuclides could not be detected in the interactions of 3He particles with 192Os. A production method involving high-current α-particle irradiation of enriched 192Os and efficient chemical separation of radioplatinum was developed. Batch yields of about 1 MBq 195mPt and 8.7 MBq 193mPt were achieved. Compared to the reactor production these batch yields are very low, but the 192Os(α,n)195mPt and 192Os(α,3n)193mPt reactions are superior with respect to the specific activity of the products which is higher by two orders of magnitude.