Preparation of no-carrier-added 211 At solutions by a simple dry distillation method in the 209 Bi( 4 He, 2n) 211 At rea
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Preparation of no‑carrier‑added 211At solutions by a simple dry distillation method in the 209Bi(4He, 2n)211At reaction Ichiro Nishinaka1,2 · Noriko S. Ishioka2 · Shigeki Watanabe2 · Ichiro Sasaki2 · Mohammad A. Azim3 Received: 17 June 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract 211 At was produced in the 209Bi(4He, 2n)211At reaction. The yield was separated from the irradiated bismuth target by a simple method, based on dry distillation. The optimized conditions of the method were studied by monitoring the astatine radioactivity with gamma-ray spectrometers. The no-carrier-added 211At solutions were prepared with eluents, namely distilled water, ethanol, methanol, or chloroform. Generally, the recovery yields obtained with the utilization of 1.6 mL of the eluent were 26–75%. The prepared 211At solutions were subjected to thin-layer chromatography and high-performance liquid chromatography to identify the chemical species present. Keywords Astatine · Dry distillation · Speciation · TLC · HPLC
Introduction An α radioactive nuclide, 211At, with half-life of 7.2 h is one of the prospective candidates for targeted alpha therapy [1]. The 211At nuclide is generally produced in the 209Bi(4He, 2n)211At reaction because of its high specific radioactivity, which is required for therapeutic purposes [2–18]. The separation of 211At from the irradiated bismuth targets has been conducted by methods based on dry- [2–12] or wetchemistry [13–18]. Generally, the methods based on drychemistry are simple, although the reproducibility of the yields in the chemical and radiolabeling reactions to identify the species therein are still challenging [14]. Further, the
* Ichiro Nishinaka [email protected] 1
Tokai Quantum Beam Science Center, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, Shirakata 2‑4, Tokai‑mura, Naka‑gun, Ibaraki 319‑1106, Japan
2
Department of Radiation‑Applied Biology, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, Watanuki 1233, Takasaki, Gunma 370‑1292, Japan
3
National Institute of Nuclear Medicine and Allied Sciences (NINMAS), Bangladesh Atomic Energy Commission (BAEC), BSMMU Campus, Shahbag, Dhaka‑1000, Bangladesh
challenge in the dry-chemistry-based method of astatine production persists. Contrarily, a complementary method of astatine production for non-clinical, fundamental research has been recently studied in the lithium-induced reaction of natPb, natPb(7Li, xn)nat−xAt [19]. A simple method, based on dry distillation, was developed to separate the produced 207−211At from the irradiated lead targets and to prepare no-carrier-added astatine solutions. The method effortlessly and successfully afforded no-carrier-added astatine solutions with high chemical purities and yields. This enabled the elucidation and speciation of astatine in the solutions prepared by dry distillation [20, 21]. The simple dry distillation method could be
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