A new internal target system for production of At-211 on the cyclotron U-120M

摘要

The alpha emitter At-211 is a radionuclide with good potential for use in the therapy of smaller tumours and metastases. However, limited availability of this radionuclide hinders development of this application and the research of astatine chemistry in general. In this general context we have designed and tested a new internal target system. A thin bismuth layer (3-5 mu m) was evaporated onto a light target backing (7.5 g) and irradiated at 0.5-1.5 degrees angles with 29.5 MeV alpha particles beam of intensity up to 30 mu A. The backing was then released from the target holder and used directly for astatine separation via dry distillation. Astatine condensed on the Teflon capillary walls was then eluted into 150-250 mu l of methanol. The saturation yield was found to be ca. 400 MBq/mu A, and the radionuclidic purity of At-211 acceptable for medical applications (activity ratio At-210/At-211 < 10(-3) at EOB). The overall separation yield was 65-75%. (c) 2005 Elsevier Ltd. All rights reserved.