bismuth213

Bismuth-213 (²¹³Bi) is a radioactive isotope of the chemical element bismuth, with a half-life of approximately 45.6 minutes. It is a member of the actinium series and is produced through the decay of actinium-225 (²²⁵Ac). Bismuth-213 is primarily used in medical applications, particularly in targeted alpha therapy (TAT), a form of radiotherapy that leverages the high linear energy transfer (LET) of alpha particles to precisely destroy cancer cells while minimizing damage to surrounding healthy tissue.

The decay chain of bismuth-213 begins with the alpha decay of ²²⁵Ac, which produces ²²¹Fr, followed by the beta decay of francium-221 (²²¹Fr) to produce astatine-217 (²¹⁷At). Astatine-217 then undergoes alpha decay to form bismuth-213, which in turn undergoes beta decay to produce polonium-213 (²¹³Po). Polonium-213 rapidly decays via alpha emission to stable lead-209 (²⁰⁹Pb). The short half-life of bismuth-213 allows for precise dosing in clinical settings, as the radiation is delivered quickly and localized to the target area.

Bismuth-213 is often used in conjunction with monoclonal antibodies or other targeting agents, such as DOTATATE or PSMA ligands, to direct the radioactive isotope to cancerous cells. This approach is particularly effective in treating certain types of blood cancers, such as multiple myeloma, and solid tumors like prostate cancer. Clinical trials have explored its potential in combination with other therapies, including chemotherapy and immunotherapy, to enhance treatment efficacy.

The production of bismuth-213 typically involves cyclotrons or other particle accelerators, where actinium-225 is generated from thorium-229 or thorium-232. Due to its short half-life and the complexity of its production, bismuth-213 is not widely available and is primarily used in specialized research and clinical settings. Ongoing research continues to explore its therapeutic potential and optimize its use in oncology.