Technetium is a chemical element with symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive; none are stable, excluding the fully ionized state of 97Tc. Nearly all technetium is produced synthetically, and only about 18,000 tons can be found at any given time in the Earth's crust. Naturally occurring technetium is a spontaneous fission product in uranium ore and thorium ore, the most common source, or the product of neutron capture in molybdenum ores. This silvery gray, crystalline transition metal lies between rhenium and manganese in group 7 of the periodic table, and its chemical properties are intermediate between those of these two adjacent elements. The most common naturally occurring isotope is 99Tc.
A synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. Examples include technetium-95 and promethium-146. Many of these are found in, and harvested from, spent nuclear fuel assemblies. Some must be manufactured in particle accelerators.
Radiopharmacology or medicinal radiochemistry is radiochemistry applied to medicine and thus the pharmacology of radiopharmaceuticals. Radiopharmaceuticals are used in the field of nuclear medicine as radioactive tracers in medical imaging and in therapy for many diseases. Many radiopharmaceuticals use technetium-99m (Tc-99m) which has many useful properties as a gamma-emitting tracer nuclide. In the book Technetium a total of 31 different radiopharmaceuticals based on Tc-99m are listed for imaging and functional studies of the brain, myocardium, thyroid, lungs, liver, gallbladder, kidneys, skeleton, blood and tumors.
A technetium-99m generator, or colloquially a technetium cow or moly cow, is a device used to extract the metastable isotope 99mTc of technetium from a source of decaying molybdenum-99. 99Mo has a half-life of 66 hours and can be easily transported over long distances to hospitals where its decay product technetium-99m is extracted and used for a variety of nuclear medicine diagnostic procedures, where its short half-life is very useful.
The pertechnetate ion is an oxoanion with the chemical formula TcO−
4. It is often used as a convenient water-soluble source of isotopes of the radioactive element technetium (Tc). In particular it is used to carry the 99mTc isotope which is commonly used in nuclear medicine in several nuclear scanning procedures.
Technetium (43Tc) is the first of the two elements lighter than bismuth that have no stable isotopes; the other such element is promethium. It is primarily artificial, with only trace quantities existing in nature produced by spontaneous fission or neutron capture by molybdenum. The first isotopes to be synthesized were 97Tc and 99Tc in 1936, the first artificial element to be produced. The most stable radioisotopes are 97Tc, 98Tc and 99Tc.
Molybdenum (42Mo) has 33 known isotopes, ranging in atomic mass from 83 to 115, as well as four metastable nuclear isomers. Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98, and 100. All unstable isotopes of molybdenum decay into isotopes of zirconium, niobium, technetium, and ruthenium.
Sodium pertechnetate is the inorganic compound with the formula NaTcO4. This colourless salt consists of the anion [TcO4]−. The radioactive 99mTcO4− anion is an important radiopharmaceutical for diagnostic use. The advantages to 99mTc include its short half-life of 6 hours and the low radiation exposure to the patient, which allow a patient to be injected with activities of more than 30 millicuries. Na[99mTcO4] is a precursor to a variety of derivatives that are used to image different parts of the body.
Technetium (99mTc) fanolesomab is a mouse monoclonal antibody formerly used to aid in the diagnosis of appendicitis. It is labeled with a radioisotope, technetium-99m (99mTc).
Technetium (99mTc) sulesomab is a mouse monoclonal antibody labelled with technetium-99m, a radionuclide, for imaging with a gamma camera.
Technetium-99m is a metastable nuclear isomer of technetium-99, symbolized as 99mTc, that is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used medical radioisotope.
Technetium (99mTc) arcitumomab is a drug used for the diagnostic imaging of colorectal cancers, marketed by Immunomedics. It consists of the Fab' fragment of a monoclonal antibody and a radionuclide, technetium-99m.
Technetium (99mTc) nofetumomab merpentan is a mouse monoclonal antibody derivative used in the diagnosis of lung cancer, gastrointestinal, breast, ovary, pancreas, kidney, cervix, and bladder carcinoma. The antibody part, nofetumomab, is attached to the chelator merpentan, which links it to the radioisotope technetium-99m (99mTc).
Technetium (99mTc) medronic acid is a pharmaceutical product used in nuclear medicine to localize bone metastases as well as other diseases that can alter the natural turn-over in the bone by bone scintigraphy.
Technetium-99 (99Tc) is an isotope of technetium which decays with a half-life of 211,000 years to stable ruthenium-99, emitting beta particles, but no gamma rays. It is the most significant long-lived fission product of uranium fission, producing the largest fraction of the total long-lived radiation emissions of nuclear waste. Technetium-99 has a fission product yield of 6.0507% for thermal neutron fission of uranium-235.
ATC code V09Diagnostic radiopharmaceuticals is a therapeutic subgroup of the Anatomical Therapeutic Chemical Classification System, a system of alphanumeric codes developed by the WHO for the classification of drugs and other medical products. Subgroup V09 is part of the anatomical group V Various.
Technetium (99mTc) exametazime is a radiopharmaceutical sold under the trade name Ceretec, and is used by nuclear medicine physicians for the detection of altered regional cerebral perfusion in stroke and other cerebrovascular diseases. It can also be used for the labelling of leukocytes to localise intra-abdominal infections and inflammatory bowel disease. Exametazime is sometimes referred to by its chemical name of hexamethylpropyleneamine oxime or HMPAO.
Technetium (99mTc) votumumab is a human monoclonal antibody labelled with the radionuclide technetium-99m. It was developed for the detection of colorectal tumors, but has never been marketed.
