Cross-section measurements for the formation of manganese-52 and its isolation with a non-hazardous eluent

With respect to the production of no-carrier-added Mn-52 nuclear reactions on natural chromium were investigated. Cross sections of the reactions Cr-nat(p, x)V-48, Cr-48,Cr-49,Cr-51, Mn-52g,Mn-m were determined in the proton energy range of 7.6 to 45MeV. Additionally, production yields of Mn-52g,Mn-m and Cr-51 were measured in the energy range from 8.2 to 16.9MeV and therefrom the calculated saturation thick target yields were obtained as (2.55 +/- 0.31), (6.96 +/- 0.57), and (1.53 +/- 0.15) GBq/mu A, respectively. For in vivo applications like PET, low toxicity is critical and sufficient activity of a radiolabelled compound mandatory. Thus, additional purification steps after separation of radionuclides and target materials have to be avoided. However, no isolation procedure has been reported in the literature so far where radiomanganese is directly obtained in a nonhazardous solution. Therefore a new separation procedure was developed utilizing the cation-exchange resin DOWEX 50Wx8 (H+-form). Mn-52g was quantitatively isolated from "bulk" chromium after 3 to 4 h in non-hazardous 0.067 M ammonium citrate solution. Up to 99% of Mn-52g activity was harvested within 10 to 15 mL eluent solution with no measureable Cr-51 impurities.