Separation of arsenic from germanium oxide targets by dry distillation

Positron-emitting isotopes of arsenic, As-70 (T-1/2 = 53 min), As-71 (T-1/2 = 64 h), (72)AS (T-1/2 = 26 h), and As-73 (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-t argets is presented. Dry distillation of GeO2 at 1105 degreesC during 2 hou rs provides a separation efficiency of more than 60%. The loss of target ma terial is less than one per cent and the irradiated targets can be used sev eral times. The method allows production of diagnostically useful amounts o f positron-emitting arsenic isotopes using accelerators commonly available at PET-centres.