Astatine-211: Production and Availability

The 7.2-h half life radiohalogen (211) At offers many potential advantages for targeted alpha-particle therapy; however, its use for this purpose is constrained by its limited availability. Astatine-211 can be produced in reasonable yield from natural bismuth targets via the Bi-209(alpha,2n)(211) At nuclear reaction utilizing straightforward methods. There is some debate as to the best incident alpha-particle energy for maximizing (211) At production while minimizing production of (210) At, which is problematic because of its 138.4-day half life alpha-particle emitting daughter, (210) Po. The intrinsic cost for producing (211) At is reasonably modest and comparable to that of commercially available I-123. The major impediment to (211) At availability is attributed to the need for a medium energy alpha-particle beam for its production. On the other hand, there are about 30 cyclotrons in the world that have the beam characteristics required for (211) At production.