erbium-169

Erbium-169 is a radioactive isotope of the element erbium, belonging to the lanthanide series. It has a half-life of approximately 9.4 days and decays primarily by beta emission with very low energy gamma radiation[1][8]. The average radiation penetration is about 0.3 mm in soft tissues and up to 1.1 mm in radiosynoviorthesis applications[1][5]. In medicine, it is most commonly used as colloid erbium citrate (erbium citrate er‑169) for radiosynovectomy—a procedure where the radiopharmaceutical is injected directly into small joints affected by chronic rheumatoid arthritis that are resistant to standard treatments or when corticosteroids are contraindicated[1][2][5]. The emitted beta particles induce necrosis of superficial synovial layers, followed by phagocytosis and reduction in inflammation, leading to improved joint function[1]. Research also suggests potential for use in targeted radionuclide therapy for metastatic cancers due to its favorable emission profile and limited tissue penetration[7][8].

Other names

erbium, isotope of mass 16915840-13-8UB95H8270HUB-95H8270HUB 95H8270H