医療用Ac-225製造に向けた海水中ラジウムの回収技術の研究

Development of Ra in the sea water collection technology for production of medical tracer Ac-225

小栗 香里 ; 荒井 陽一 ; 渡部 創  ; 瀬古 典明*; 保科 宏行*

Oguri, Kaori; Arai, Yoichi; Watanabe, So; Seko, Noriaki*; Hoshina, Hiroyuki*

医療用Acの安定した国内生産を目指し、原料となるRaを海水から効率良く、採取する技術を開発するため、様々な吸着材を合成しRaのアナログ元素であるBaを代替元素として評価した。その結果、1段階目にリン酸型(P)グラフト重合吸着材を用い、次いで吸着したBaを含む数種の元素を溶出させた酸溶液を、TEHDGA/SiO-P充填カラムに通液することでBaのみを分離できることを見いだした。これにより、海水中のRaを資源利用できる見込みが得られた。

Radium-226 (Ra) has recently attracted attention as a source for the production of Actinium-225 (Ac), which can be used for the alpha-particle treatment of cancer. Ra is present in approximately 10,000 tons in the sea. The amount of Ra in seawater could help patients with metastatic cancer around the world. Therefore, we focused on the extraction of Ra from seawater and examined an effective process for refining Ra. Due to the low concentration of Ra in seawater, only a few ppb, it has not received much attention in terms of economic point. Therefore, we focused on adsorbents prepared by Radiation-Induced Graft Polymerization to selectively collect Ra. In this study, we performed adsorption studies with Barium (Ba), homologs element of Ra, which may coexist with Ra in seawater.