Evaluation of an internal cyclotron target for the production of 211At via the 209Bi (α,2n)211At reaction

Astatine-211 is a 7.2 h half-life α-emitting radionuclide which has shown great promise for targeted radiotherapy. It is generally produced by cyclotron bombardment of bismuth metal targets with 28 MeV α-particles via the 209Bi(α,2n)211At reaction. In order to provide 211At activity levels anticipated for clinical investigations, an internal target system has been designed and evaluated. The system has a grazing-angle configuration and leading- and trailing-edge monitors. Both aluminum and copper target backings were evaluated. With approx. 28MeV α-particles, the 211At production efficiency was 41 ± 7 MBq/μA·h, compared with 10.6 ± 1.2 MBq/μA·h for an external target. Radionuclidic purity of 211At was high with no evidence of 210At.