Bi211

Bismuth-211 (Bi-211) is a radioactive isotope of the element bismuth with a mass number of 211. It has Z = 83 and is not naturally abundant. Bi-211 decays by alpha emission with a half-life of about 2.14 days, predominantly transforming into thallium-207 (Tl-207). The alpha decay releases high-energy alpha particles over a short range.

Bi-211 is produced in nuclear facilities, including particle accelerators and high-flux reactors, through target irradiation and subsequent chemical separation to isolate the desired isotope. The production process requires specialized radiochemical handling to prevent contamination and ensure purity, since alpha emitters pose significant radiological hazards if ingested or inhaled.

In recent years, Bi-211 has attracted interest for targeted alpha therapy (TAT) in oncology. When attached to tumor-targeting molecules such as monoclonal antibodies or peptides, Bi-211 delivers cytotoxic alpha radiation directly to cancer cells while minimizing exposure to surrounding healthy tissue. The short track and high linear energy transfer of alpha particles can be advantageous for destroying isolated cancer cells and micrometastases. Research continues to optimize chelation strategies, delivery methods, and clinical applications.

Safety and regulatory considerations for Bi-211 reflect the hazards of alpha-emitting radiopharmaceuticals. Handling requires specialized facilities, protective equipment, shielding, and strict waste management. Peering into future applications, Bi-211 remains under investigation as a component of precision radiopharmaceutical therapies, with emphasis on targeted delivery and patient safety.