Excitation functions and yields for Re-186g production by proton and deuteron cyclotron irradiation

The 186gRe is a beta-gamma emitter that, thanks to its suitable nuclear properties (t1/2 = 90.64 h, Emax-beta 1.07, 0.93 MeV, main E-gamma 137 keV), is presently used in palliation metabolic radiotherapy, with optimal perspectives for applications in radioimmunotherapy (RIT) too. In particular the energy range of the beta particles suggests that this radionuclide is a good candidate for cancers with small dimensions (from few mm to a few cm in soft tissue). The possibility to use this radionuclide for therapeutic purposes is strictly related to the possibility of increasing its specific activity (AS). This improvement is reached by substituting the common 185Re(n,gamma) production route in thermal nuclear reactor with the 186W(p,n) and/or (d,2n) cyclotron production ones, due to the possibility of radiochemical separation of the product from the target in no-carrier-added form, reaching a AS(NCA) value close to the theoretical carrier-free one AS(CF) = 6.88 GBq.microg-1.