Assessing the 210At impurity in the production of 211At for radiotherapy by 210Po analysis via isotope dilution alpha spectrometry

A method for assessing the impurity At-210 in cyclotron-produced At-211 via isotope dilution alpha spectrometry is presented. The activity of At-210 is quantified by measuring the activity of daughter nuclide Po-210. Counting sources are prepared by spontaneous deposition of Po on a silver disc. Activity of At-210 (at the time of Po-210 maximum activity) is found to be 83.5 +/- 9.0 Bq, corresponding to an atom ratio (At-210:At-211 at the time of distillation) of 0.010 +/- 0.007% (k = 2). The method produces high-quality alpha spectra, with baseline alpha-peak resolution and chemical yields of greater than 85%. (c) 2006 Elsevier Ltd. All rights reserved.