Applicability of radionuclides emitting low energy beta for unsealed source radiotherapy

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K10303
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Radiation science
• Research Institution: National Institutes for Quantum and Radiological Science and Technology
• Principal Investigator: Kikuchi Tatsuya 国立研究開発法人量子科学技術研究開発機構, 放射線医学総合研究所 標識薬剤開発部, 主幹研究員(定常) (90392224)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 放射線内用療法 / 軟β線 / 14C / 35S

Outline of Final Research Achievements

In the cancer therapy using radiopharmaceuticals, radionuclides that emits　beta particles with high energy have traditionally been used. Recently, the application of radionuclides that emits alfa particles or auger electrons are investigated for the treatment of tumor. In the development of a radiopharmaceutical labelled with these radionuclides, we often encounter difficulties such as low labelling efficiency and low in vivo stability. These issues could be overcome by the use of 14C, a low energy beta emitter, although 14C have not been applied for this purpose. Here, the applicability of 14C for the cancer therapy was investigated. As a 14C carrier, 2-aminoisobutyric acid (AIB) that is stable in vivo and is highly accumulated in tumor was used. The growth of tumor was dramatically suppressed by the injection of [14C]AIB to tumor-bearing mice, although significant histological damages were not observed in the kidney and pancreas, in which [14C]AIB is highly accumulated.

Free Research Field

放射線科学

Academic Significance and Societal Importance of the Research Achievements

本研究結果は、14Cが放射線内用療法に適した非常に有望な放射性核種であることを初めて示した。14Cの物理的半減期が長いことにより正常組織への被ばくの増大が懸念されるが、腫瘍集積性が高く生物学的半減期の比較的短い化合物の使用や、14C とほぼ同等のエネルギーを持つβ-を放出する比較的短半減期の35Sを用いることなどにより、無用な体内被ばくを低減することが期待できる。14Cは様々な有機化合物にその化学構造を変化させずに導入可能であることから、柔軟な薬剤設計が可能となり、より良い放射線内用療法用の薬剤が開発されると期待される。