Next-generation medical radio isotope production with inverse kinematics fusion reactions; On-line nuclear medicine treatment without chemical separation

田中 泰貴; 遊津 拓洋  ; 重河 優大*

Tanaka, Taiki; Asozu, Takuhiro; Shigekawa, Yudai*

Targeted alpha-therapy has been used for several patients who have radioactive iodine-refractory thyroid cancer, as a preclinical trial. The alpha emitter, At, half-life 7.2 hours, was made using the alpha-particle beam irradiation into Bi target. The beam energy was set ~28 MeV not to synthesize At as the daughter nuclei Po, half-life 138 days, is a poison. However, the restriction reduces the At production rate about a quarter with respect to the full coverage of the excitation function of the cross-section. In addition, the chemists need to separate At from the Bi target as soon as possible after the beam irradiation with managing the high radiation from the products. It is anticipated an ideal method to increase the production rate of At with separating from At, as well as no chemical separation. Here we show that the method to produce At with inverse kinematics fusion reactions, which 209Bi beam irradiates to the He gas target. We found this method can separate At isotopes from the target as the productions have much higher kinematics energy so that the productions automatically exit from the target. In addition, the productions can be separated by the magnetic rigidity analysis with the dipole magnet, e.g., At and At make the focus at the different positions. The products are separated just after the beam irradiation, and it is available with transportation system, such as gas-catcher and gas-transportation system. Connecting between the At production room and the medical treatment room by the gas-transport system, enables us to do on-line nuclear medicine treatment ( 10 sec), without losing the products due to the half-life. This method can also apply for the medical radio isotope who has shorter half-life, such as At etc., which has a potential to open many new types of medical treatment using the differences of the half-life and the chemical property.