Indium-111 Explained
Symbol: | In |
Mass Number: | 111 |
Num Neutrons: | 62 |
Num Protons: | 49 |
Abundance: | syn |
Halflife: | [1] |
Decay Product: | cadmium-111 |
Decay Symbol: | Cd |
Decay Mass: | 111 |
Decay Mode1: | EC |
Decay Energy1: | 0.860 |
Indium-111 (111In) is a radioactive isotope of indium (In). It decays by electron capture to stable cadmium-111 with a half-life of 2.8 days.[2] Indium-111 chloride (111InCl) solution is produced by proton irradiation of a cadmium target (112Cd(p,2n) or 111Cd(p,n)) in a cyclotron, as recommended by International Atomic Energy Agency (IAEA).[3] The former method is more commonly used as it results in a high level of radionuclide purity.
Indium-111 is commonly used in nuclear medicine diagnostic imaging by radiolabeling targeted molecules or cells. During its radioactive decay, it emits low energy gamma (γ) photons which can be imaged using planar or single-photon emission computed tomography (SPECT) gamma cameras (primary energies (ε) of 171.3 keV (91%) and 245.4 keV (94%))
Uses in nuclear medicine
When formulated as an 111InCl solution, it can be used to bind antibodies, peptides, or other molecular targeted proteins or other molecules, typically using a chelate to bind the radionuclide (in this case 111In) to the targeting molecule during the radiosynthesis/ radiolabeling process, which is tailored to the desired product.
111In labeled antibodies
- Ibritumomab Tiuxetan; Zevalin - For dosimetry estimates prior to 90Y immunotherapy for lymphoma
- 111In ProstaScint — PSMA antibody imaging of prostate cancer
111In labeled peptides
- 111In pentetreotide (including in 111In (diethylenetriaminopentaacetic (DTPA)-octreotide) and Octreoscan)
- Octreotide is an somatostatin receptor inhibitor pharmaceutical which binds with high affinity to somatostatin receptors 2 and 5, interfering with normal receptor function. It is used as a drug to treat several neuroendocrine tumors in which somatostatin receptors are overexpressed or overactive. Examples include:
- Sympathoadrenal system tumors: pheochromocytoma, neuroblastoma, ganglioneuroma, paraganglioma
- Gastroenteropancreatic (GEP) tumors: carcinoid, insulinoma
- Medullary thyroid cancer, pituitary adenoma, small cell lung cancer
- 111In pentetreotide imaging can identify the presence, levels of somatostatin receptor 2,5 expression, extent of disease and response to therapy
111In can also be formulated in the chemical form 111In oxyquinoline (oxine)[4] for labeling blood cells and components
See also
Notes and References
- Book: Table of Radionuclides, Vol. 3. 2006. Bureau international des poids et mesures. 92-822-2218-7. 75. 26 June 2017.
- Web site: FDA Label Document:Indium In-111 Chloride Sterile Solution. www.accessdata.fda.gov. 20 Aug 2018.
- Takács. S.. Tárkányi. F.. Hermanne. A.. Dec 2005. Validation and upgrading of the recommended cross-section data of charged particle reactions: Gamma emitter radioisotopes. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 240. 4. 790–802. 10.1016/j.nimb.2005.06.209. 2005NIMPB.240..790T . 0168-583X.
- Web site: PubChem In-111 Oxyquinoline. pubchem.ncbi.nlm.nih.gov. 20 Aug 2018.
- Web site: IN-111 FACT SHEET. Nordion(Canada), Inc.. 23 September 2012. dead. https://web.archive.org/web/20111203082605/http://www.nordion.com/documents/products/In-111_Can.pdf. 3 December 2011.