Lead-212 (212Pb)

Lead-212 (Pb-212) is a radioactive isotope of lead with a half-life of approximately 10.6 hours, primarily utilized as a potent therapeutic radionuclide payload in targeted alpha therapy (TAT) (NIH, 2024; MDPI, 2025). It is not a biological target itself, such as a receptor or enzyme, but rather the cytotoxic component of radiopharmaceuticals designed to deliver localized radiation to specific cellular targets (Open MedScience, 2025). Pb-212 acts as an in vivo generator for its daughter isotope, Bismuth-212 (Bi-212), which emits high-energy alpha particles with a short tissue range of less than 100 micrometers (BioEmTech, 2025; NIH, 2024). This high linear energy transfer (LET) radiation causes dense, difficult-to-repair double-strand DNA breaks, leading to effective cell death in targeted tumors while sparing surrounding healthy tissue (UroToday, 2025; Open MedScience, 2025). Lead-212 is typically conjugated to targeting moieties like peptides or antibodies that bind to antigens such as prostate-specific membrane antigen (PSMA) or somatostatin receptor 2 (SSTR2) (ResearchGate, 2025). This approach is particularly effective for treating micrometastatic disease and cancers resistant to conventional beta-emitting radiopharmaceuticals (Open MedScience, 2025). Clinical development of Pb-212-based drugs involves monitoring for safety concerns such as myelosuppression and nephrotoxicity, as well as managing radiation safety due to high-energy gamma emissions from decay products like Thallium-208 (SNM Journals, 2019; UroToday, 2025).

Other names

Pb-212[212Pb]LeadThorium B

Lead-212 acts as an in vivo generator of Bismuth-212, which emits high-energy alpha particles that cause lethal double-strand DNA breaks in targeted cells.