terbium-161

Terbium-161 is a radioactive isotope of the rare earth element terbium used as a radiopharmaceutical for targeted radionuclide therapy and theranostic applications in oncology. It emits beta particles similar to lutetium-177 but also releases a substantial number of short-ranged conversion and Auger electrons per decay. These emissions result in higher local dose density within small tumor volumes (0.5–30 μm), making it particularly effective at eradicating microscopic metastases or single cancer cells that are often responsible for relapse and metastatic spread[1][2][4][7]. Terbium-161 can be conjugated to targeting molecules such as antibodies or small molecules (e.g., PSMA ligands) for selective delivery to tumor cells[4][6]. Its half-life is approximately 6.9 days[7], which allows practical transport and clinical use while ensuring rapid decay post-treatment. Preclinical studies have shown that terbium-161-labeled compounds are more effective than their lutetium-177 analogs at inducing DNA damage and cell death in cancer cells due to the additional emission of Auger electrons[2][7]. Early-phase clinical trials have demonstrated promising efficacy with an acceptable safety profile in patients with metastatic castration-resistant prostate cancer using [^161Tb]Tb-labeled PSMA-targeting agents[4][6]. The isotope is also being investigated for other cancers including lymphoma[7].

Other names

terbium-161terbium161terbium 161Tb-161 chloride (NCA)terbium radioisotope