Evaluation of Mo/Tc production with irradiated MoO pellets
照射済みMoO ペレットによるMo/Tc製造に関する評価
石田 卓也; 椎名 孝行*; 太田 朗生*; 鈴木 善貴 ; 柴田 晃 ; 西方 香緒里 ; 木村 明博 ; 棚瀬 正和*; 小林 正明*; 佐野 忠史*; 藤原 靖幸*; 土谷 邦彦
Ishida, Takuya; Shiina, Takayuki*; Ota, Akio*; Suzuki, Yoshitaka; Shibata, Akira; Nishikata, Kaori; Kimura, Akihiro; Tanase, Masakazu*; Kobayashi, Masaaki*; Sano, Tadafumi*; Fujihara, Yasuyuki*; Tsuchiya, Kunihiko
Tcは放射性医薬品として最も使われる放射性同位元素の一つであり、親核種であるMoから生成される。(n, )方法によるMo/Tc製造技術開発を行っているが、本法で得られるMoの比放射能は、核分裂方法((n, f)方法)に比べると低く、抽出されたTc溶液の放射能濃度も低いことが欠点である。本研究では、Tc溶液の高い放射能濃度を得るため、Mo/Tc分離/抽出/濃縮試験を行った。試験手順として、(1)京都大学原子炉(KUR)で高密度MoOペレットの照射、(2) MEKを用いた溶媒抽出による回収、(3)Tc溶液の精製・濃縮、及び(4)Tc溶液の品質検査を行った。その結果、照射済みMoOペレットを6M-NaOH溶液で溶解し、Mo/Tc溶液からのTc回収率は目標値である805%を達成した。さらに、得られたTc溶液の放射性核種純度、放射化学的異物等の検査は、基準値を満足した。
Technetium-99m (Tc) is one of the radioisotopes which are used most as radiopharmaceuticals, and it is obtained from the parent nuclide of Molybdenum-99 (Mo). However, the specific radioactivity of Mo by (n, ) method is extremely low compared with that by fission method ((n,f) method), and as a result, the radioactive concentration of the extracted Tc solution is also low. Thus, it is necessary for the high radioactive concentration of the Tc solution to develop the Mo/Tc separation/extraction/concentration method. In this study, the experiments of Mo/Tc production were performed to enhance recovery yields of Tc and to get a high quality of Tc product. The procedures are described as follows. (1) High-density MoO pellets were irradiated in the Kyoto University Research Reactor (KUR). (2) Tc was extracted with MEK. (3) Tc extracted in MEK was purified and concentrated with acidic alumina column. (4) Product of Tc solution was checked in several factors such as radionuclidic and radiochemical purities. The irradiated MoO pellets were dissolved in 6M-NaOH and the Mo/Tc solution was treated with the devices. From the results, the Tc recovery yields achieved 805% of our goal. Finally, the extracted Tc solution passed the quality inspection of six items.