Pertechnetate
Encyclopedia
The pertechnetate ion is an oxoanion with the chemical formula TcO4−. 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 Tc-99m isotope (half-life 6 hours) which is commonly used in nuclear medicine
in several nuclear scanning procedures.
A technetate(VII) is a compound containing this ion. Pertechnetates are salts of technetic(VII) acid
. Pertechnetate is analogous to permanganate
but it has little oxidizing power.
, also known as a cow, provides the pertechnetate containing the short-lived isotope Tc-99m for medical uses. This compound is generated directly from molybdate held on alumina within the generator (see this topic for detail). Since technetate(VII) can substitute for iodine
in the Na/I Symporter (NIS) Channel in follicular cells of the thyroid
gland, inhibiting uptake of iodine into the follicular cells. Tc99m-pertechnetate is used for nuclear medicine
imaging of the thyroid gland.
Technetate(VII) radiolabeled with Tc99m is also the marker injected into the body looking for ectopic gastric tissue as is found in a Meckel's diverticulum
. This nuclear imaging study is otherwise known as a "Meckel's Scan".
. In theory, the longest-lived technetium isotope, Tc-97
(half-life 2.6 million years), would be the optimal isotope for this use.
Solutions of technetate(VII) react with the surface of iron
to form technetium
dioxide, in this way it is able to act as an anodic corrosion inhibitor
.
Technetium
Technetium is the chemical element with atomic number 43 and symbol Tc. It is the lowest atomic number element without any stable isotopes; every form of it is radioactive. Nearly all technetium is produced synthetically and only minute amounts are found in nature...
(Tc). In particular it is used to carry the Tc-99m isotope (half-life 6 hours) which is commonly used in nuclear medicine
Nuclear medicine
In nuclear medicine procedures, elemental radionuclides are combined with other elements to form chemical compounds, or else combined with existing pharmaceutical compounds, to form radiopharmaceuticals. These radiopharmaceuticals, once administered to the patient, can localize to specific organs...
in several nuclear scanning procedures.
A technetate(VII) is a compound containing this ion. Pertechnetates are salts of technetic(VII) acid
Pertechnetic acid
Technetium oxide is the chemical compound with the formula Tc2O7. This yellow volatile solid is a rare example of a molecular binary metal oxide, the other examples being RuO4, OsO4, and the unstable Mn2O7...
. Pertechnetate is analogous to permanganate
Permanganate
A permanganate is the general name for a chemical compound containing the manganate ion, . Because manganese is in the +7 oxidation state, the permanganate ion is a strong oxidizing agent. The ion has tetrahedral geometry...
but it has little oxidizing power.
Use of pertechnetate to carry technetium-99m
A technetium-99m generatorTechnetium-99m generator
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...
, also known as a cow, provides the pertechnetate containing the short-lived isotope Tc-99m for medical uses. This compound is generated directly from molybdate held on alumina within the generator (see this topic for detail). Since technetate(VII) can substitute for iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
in the Na/I Symporter (NIS) Channel in follicular cells of the thyroid
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
gland, inhibiting uptake of iodine into the follicular cells. Tc99m-pertechnetate is used for nuclear medicine
Nuclear medicine
In nuclear medicine procedures, elemental radionuclides are combined with other elements to form chemical compounds, or else combined with existing pharmaceutical compounds, to form radiopharmaceuticals. These radiopharmaceuticals, once administered to the patient, can localize to specific organs...
imaging of the thyroid gland.
Technetate(VII) radiolabeled with Tc99m is also the marker injected into the body looking for ectopic gastric tissue as is found in a Meckel's diverticulum
Meckel's diverticulum
A Meckel's diverticulum, a true congenital diverticulum, is a small bulge in the small intestine present at birth. It is a vestigial remnant of the omphalomesenteric duct , and is the most frequent malformation of the gastrointestinal tract...
. This nuclear imaging study is otherwise known as a "Meckel's Scan".
Uses of pertechnetate which do not rely on its radioactivity
All technetium salts are mildy radioactive, but some of them have explored use of the element for its chemical properties. In these uses, its radioactivity is incidental, and generally the least radioactive (longest lived) isotopes of Tc are used. In particular, Tc-99 (half-life 211,000 years) is used in corrosion research, because it is the decay product of the easily-obtained commercial Tc-99m isotope, which is its nuclear isomerNuclear isomer
A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons . "Metastable" refers to the fact that these excited states have half-lives more than 100 to 1000 times the half-lives of the other possible excited nuclear states...
. In theory, the longest-lived technetium isotope, Tc-97
Isotopes of technetium
Technetium is the first of the two elements in the first 82 that have no stable isotopes ; the other such element is promethium. It is primarily artificial, only trace quantities existing in nature produced by spontaneous fission or neutron capture by molybdenum...
(half-life 2.6 million years), would be the optimal isotope for this use.
Solutions of technetate(VII) react with the surface of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
to form technetium
Technetium
Technetium is the chemical element with atomic number 43 and symbol Tc. It is the lowest atomic number element without any stable isotopes; every form of it is radioactive. Nearly all technetium is produced synthetically and only minute amounts are found in nature...
dioxide, in this way it is able to act as an anodic corrosion inhibitor
Corrosion inhibitor
A corrosion inhibitor is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy. The effectiveness of a corrosion inhibitor depends on fluid composition, quantity of water, and flow regime...
.