Accurate determination of half life and radionuclidic purity of reactor produced 177gLu(177mLu) for metabolic radiotherapy

Thanks to its favorable decay characteristics, 177gLu is finding several applications in nuclear medicine, especially for palliative metabolic radiotherapy of cancer and radioimunotherapy. 177gLu is produced in thermal nuclear reactor either by direct neutron capture 176Lu(n,γ)177(m+g)Lu on either natural or enriched 176Lu target, or by reaction on enriched 176Yb target followed by negatron decay. The latter method does produce a high radionuclidic purity and high specific activity radionuclide in no-carrier-added form, since 177Yb decays solely to the ground state 177gLu. Conversely, the first method does produce a low specific activity 177gLu in carrier-added form,1 contaminated by the long-lived radioisotopic impurity 177mLu. The accurate determination of radionuclidic purity and half-life of 177gLu carried out by HPGe and LSCS is presented in some details.