Separation of arsenic from germanium oxide targets by dry distillation

Positron-emitting isotopes of arsenic, 70As (T 1/2 = 53 min), 71As (T 1/2 = 64 h), 72As (T 1/2 = 26 h), and 73As (T 1/2 = 17.8 d) are of interest in biomedical investigations using PET. A fast and simple method for their production using low-energy proton and deuteron reactions on enriched Ge-targets is presented. Dry distillation of GeO2 at 1105 °C during 2 hours provides a separation efficiency of more than 60%. The loss of target material is less than one per cent and the irradiated targets can be used several times. The method allows production of diagnostically useful amounts of positron-emitting arsenic isotopes using accelerators commonly available at PET-centres.