Thick target yield measurement of 211At through the nuclear reaction 209Bi(alfa, 2n)

Radionuclide Therapy (RNT) and Radioimmunotherapy (RIT) are potentially of great interest for cancer therapy. In many therapeutic applications alpha emitters should be much more effective than already-approved beta emitters due to the short range and high linear energy transfer of alpha particles. 213Bi is an important alpha emitter already used in clinical trials but the half-life of this radioisotope is short (46 minutes) and so its use is limited for certain therapies. 211At is potentially very interesting for medical purposes because of its longer half-life of 7.2 hours, and suitable decay scheme. We have studied the cyclotron-based production of 211At via the reaction 209Bi(alfa, 2n), this production route probably being the most promising in the long term. The energy dependence of thick target yields and the reaction cross sections for the production of 211At and 210At were determined and found to be in good agreement with literature. The best energy to produce 211At is 28-29 MeV. The possible production of the undesired, highly radiotoxic, and long-lived alpha-emitting 210Po (138.38 days), which is produced from decay of 210At, is also discussed.