Indium-111 (111In)

Indium-111 is a radioactive isotope of indium that decays by electron capture to stable cadmium-111 with a physical half-life of approximately 2.8 days (67.2 hours)[1][4][9][10]. It emits gamma photons at energies of 171 keV and 245 keV, making it suitable for detection through gamma cameras and SPECT imaging[1][4][5][9]. Indium-111 is not a biological target (such as a receptor, enzyme, or transporter) but is a radioisotope used as a diagnostic tracer in nuclear medicine. It is commonly used to label biological molecules, cells, antibodies, or peptides for imaging the localization of tumors (e.g., indium-111 pentetreotide for neuroendocrine tumors), sites of infection, or inflammation (e.g., indium-111-labeled leukocytes)[5][6][7]. As such, "Indium-111 decay emission tracer" is not a canonical biological target, but rather the radioisotope component of diagnostic radiopharmaceuticals. It does not have intrinsic biological function or act as a "therapeutic target"[1][6][7][9]. Summary of errors/limitations in the target name "Indium-111 decay emission tracer": - It is not a therapeutic target, but a radioactive tracer (false positive as a target)[1][7]. - It is properly referred to as "Indium-111" or "111In" in the context of radiopharmaceuticals[1][6][7]. - Its function, safety, and disease associations depend on the ligand or construct to which it is attached (e.g., octreotide, antibodies, leukocytes)[5][6][7]. - No canonical therapeutic drugs "interact" with indium-111 as a target; instead, drugs or biomolecules are labeled with it for imaging[7]. - Molecular classification is "Other" (radioisotope), not receptor, enzyme, transporter, etc. If you are seeking information on a nuclear medicine imaging tracer labeled with indium-111 (such as "indium-111 pentetreotide" or "indium-111 chloride-labeled leukocytes"), you should specify the biomolecule or target rather than the decay emission tracer itself. Indium-111 is an imaging tool, not a molecular therapeutic target[1][5][6][7][9].

Other names

Indium-111 tracer111In radiotracerIndium-111 emissionIndium-111 chlorideIndium-111 pentetreotide (when chelated to peptides)Indium-111 oxyquinoline (when chelated for cell labeling)111In tracer

*Not applicable*; indium-111 acts as a gamma-emitting radioisotope detected in radiopharmaceuticals[1][6][7] - Mechanism depends on the compound it labels (e.g., binds somatostatin receptor in case of 111In-pentetreotide[6])