Recent progress of astatine-211 in endoradiotherapy: Great advances from fundamental properties to targeted radiopharmaceuticals

Astatine-211 ( 211 At, t 1/2 = 7.21 h) emitting two α particles with energies of 5.87 and 7.45 MeV, can lead to a high linear energy transfer (LET = 98.84 keV/µm) and short tissue range (50∼90 µm). Since the 1950s, 211 At had stepped into endoradiotherapy and has always been regarded as one of the most promising α -emitters for targeted-alpha therapy (TAT) in various malignancies. In the past two decades, 211 At related radiopharmaceuticals have achieved great progress in the studies of basic physicochemical properties of astatine, 211 At labeling strategies, preclinical and clinical studies, producing profound effects in nuclear medicine. This work will give a panorama of 211 At-related researches in the recent 20 years, which will cover both the fundamental insights of 211 At radiochemistry and applied labeling compounds. It can provide some important hints for the studies of TAT and other radiopharmaceuticals applied in tumor radiotherapy. This work systematically introduced the progress of astatine-211 in endoradiotherapy, including the fundamental properties of astatine, the newly-developed 211 At labeling strategies, the preclinical and clinical advances of 211 At-based radiopharmaceuticals.