Two ways to establish potential At-211 radiopharmaceuticals

The special radiophysical characteristics of the alpha emitting cyclotron radionuclide At-211 favour its therapeutic application. Studies for therapeutic use have been carried out over the past 15 years. Labelling reactions with this heavy halogen and characterization of the products are important because of the low concentrations used in treatment (non carrier added level). One successful way to produce At-211 radiopharmaceuticals is the labelling of aromatic iodine compounds with At-211 via isotope exchange or reaction of organostannyl precursors with astatine. These products enter the tumour by its metabolism. To a certain extent, the intraarterial application of At-211 labelled particles seems to be a promising alternative to intravenous application, causing selective accumulation of therapeutic At-211 doses as shown by the first alpha endoradiotherapy of a incurable recurrent lingual carcinoma.