Ansari-Chauveau S, Frelin A-M, de France G, Guertin A, Haddad F, Ledoux X, Mrázek J, Šimečková E
GANIL, Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Boulevard H. Becquerel, Caen 14076, France.
GANIL, Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Boulevard H. Becquerel, Caen 14076, France.
Appl Radiat Isot. 2025 Nov;225:112061. doi: 10.1016/j.apradiso.2025.112061. Epub 2025 Jul 30.
Targeted Alpha Therapy (TAT) offers a promising approach to treat cancer, particularly micrometastases, by utilizing the short range and high linear energy transfer of alpha particles emitted by radionuclides. At (half-life 7.2h) is one of the promising alpha emitters (only one alpha emitted during decay) that has been identified for nuclear medicine applications. It belongs to the halogen family and shares chemical properties with iodine, an element used for imaging (I, I and I) and also widely used to treat thyroid cancer (I). This chemical similarity enables the use of Iodine as an analogue for biodistribution and dosimetry studies while using At for treatment in a theranostic approach. In this study, an alpha beam accelerated by SPIRAL2, was used to produce At via the reaction Bi(α, 2n)At on the NFS beam line. The production cross section of At increases with increasing alpha energy up to 31 MeV. However, above 28.6 MeV, the production of At occurs via the Bi(α, 3n)At reaction. At decays to Po, a highly toxic alpha-emitting radionuclide with a half-life of 138.3 days which cannot be separated chemically. Therefore, it is crucial to have a thorough understanding of the rise in At production to optimize the generation of At while minimizing the production of At To achieve this, Bi targets were irradiated at various alpha beam energies between 28 to 31 MeV with high precision thanks to the characteristics of SPIRAL2 accelerator and At cross sections were measured by using γ-ray spectroscopy. The incident particle flux was monitored using an instrumented Faraday cup. This flux measurement combined with the number of detected γ-rays allowed to determine the production cross sections of At as a function of energy. The results are in good agreement with experimental values recommended by the International Atomic Energy Agency (IAEA) for At and provide supplemental data for At between 28.6 and 31 MeV. The data collected in this study will help optimize the energy range of interest for the production of At and give At its rightful place as a radionuclide for TAT.
靶向α治疗（TAT）通过利用放射性核素发射的α粒子的短程和高线性能量转移，为治疗癌症，尤其是微转移瘤提供了一种很有前景的方法。砹（半衰期7.2小时）是已被确定用于核医学应用的有前景的α发射体之一（衰变过程中仅发射一个α粒子）。它属于卤素族，与碘具有相同的化学性质，碘是一种用于成像（123I、124I和125I）且也广泛用于治疗甲状腺癌（131I）的元素。这种化学相似性使得在采用治疗诊断方法使用砹进行治疗时，能够将碘用作生物分布和剂量测定研究的类似物。在本研究中，由SPIRAL2加速器加速的α束用于通过在NFS束流线上的Bi(α, 2n)At反应来产生砹。砹的生成截面随着α能量增加至31 MeV而增大。然而，在28.6 MeV以上，砹的生成是通过Bi(α, 3n)At反应发生的。砹衰变为钋，钋是一种半衰期为138.3天的剧毒α发射性核素，无法通过化学方法分离。因此，全面了解砹生成量的增加情况对于优化砹的生成、同时尽量减少钋的生成至关重要。为实现这一点，借助SPIRAL2加速器的特性，在28至31 MeV之间的各种α束能量下对铋靶进行高精度辐照，并使用γ射线光谱法测量砹的截面。使用配备仪器的法拉第杯监测入射粒子通量。这种通量测量与检测到的γ射线数量相结合，能够确定砹的生成截面作为能量的函数。结果与国际原子能机构（IAEA）推荐的砹的实验值高度吻合，并为28.6至31 MeV之间的砹提供了补充数据。本研究收集的数据将有助于优化砹生成的感兴趣能量范围，并使砹作为用于靶向α治疗的放射性核素获得应有的地位。
