## 1 Introduction  
Several research groups are evaluating the use of \(\alpha\)-particle-emitting radionuclide astatine-211 (\({}^{211}\)At) for targeted radionuclide therapy of cancer [1; 2; 3]. While there have been few clinical studies with \({}^{211}\)At-labeled radiopharmaceuticalcuticals [4; 5], preclinical studies have been directed at treatment of several different cancer types, including ovarian cancer [6; 7], glioma [8], leukemia [9; 10], lymphoma [11], breast cancer [12; 13; 14], squamous cell cancer [15; 16], and prostate cancer [17]. The high interest in use of targeted \(\alpha\)-emitters comes from potential advantages of their very high local cytotoxicity brought about by the \(\alpha\)-particle's short path length and its high linear energy transfer (LET) [18]. These and other properties of \(\alpha\)-emitters, such as high cytotoxicity independent of tissue oxygen concentration and dose rate [19; 20], provide an advantage over \(\beta\)-emitting radionuclides for some cancer therapy applications. Of the \(\alpha\)-emitting radionuclides, \({}^{211}\)At is particularly attractive, as it has negligible high-energy photon emissions and does not have any long-lived \(\alpha\)-emitting daughter radionuclide(s). Further, its half-life (7.21 h) is long enough to allow ample time for preparation, quality control and administration before an appreciable amount has decayed, but short enough for its use in an outpatient setting. Most importantly, due to its physical and radiobiological properties, \({}^{211}\)At is very attractive for use in targeted treatment of disseminated (metastatic) cancer, blood-borne cancers, minimal residual disease, and disease isolated in compartmental spaces (e.g., ovarian and pancreatic cancers in the peritoneal cavity). An effective treatment of these conditions could greatly improve the five-year survival rates in advanced stages of cancers [21]. Production of \({}^{211}\)At can be readily accomplished by irradiating a natural abundance bismuth target (_i.e._, 100% \({}^{209}\)Bi) with a cyclotron-produced \(\alpha\)-particle beam [22]. We have used this \({}^{209}\)Bi(\(\alpha\),2n) reaction to produce the \({}^{211}\)At in all of our studies. Isolation of the \({}^{211}\)At from the irradiated bismuth target is generally accomplished by dry distillation [22; 23; 24; 25; 26]. The dry distillation method for isolation of \({}^{211}\)At can be relatively efficient, providing up to 70% recovery if parameters such as temperature of oven, inert gas flow rates, and size and design of glassware are optimized. We optimized the parameters of the dry distillation isolation approach [27; 28] and used that method of isolation for nearly two decades. Even with process optimization, the recovered yields from the dry distillation varied greatly at times. In addition to that problem, more recently our bismuth target was increased in size to produce higher quantities of \({}^{211}\)At required to undertake clinical studies [29]. The increase in the size of bismuth target (and its aluminum backing) resulted in having to greatly increase the size of quartz tube used in the high temperature oven. Attempts to remove the bismuth from the aluminum backing mechanically or through heat were deemed too dangerous. An alternate method of cutting the aluminum backing with a small band saw in a charcoal filtered Plexiglas glovebox was used for a short time, but this was also deemed too dangerous for routine application. An alternate method for isolation of \({}^{211}\)At from bismuth targets is referred to as the \"wet chemistry\" isolation method [22]. In this method, the bismuth target is dissolved in nitric acid, and in subsequent steps, the \({}^{211}\)At is separated from the bismuth. The wet chemistry approach was used in early studies for isolation of \({}^{211}\)At [30,31] and has been employed more recently by other research groups [32,33].