Technetium

Basic Treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . Perform routine emergency care for associated injuries. For eye contamination, flush eyes immediately with water. Irrigate each eye continuously during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patent can swallow, has a good gag reflex, and does not drool ... . Perform routine BLS care as necessary. /Radioactives I, II, and III/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious or is in severe respiratory distress. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of 0.9% saline (NS) or lactated Ringer's (LR). For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs fo fluid overload ... . Treat seizures with diazepam or lorazepam ... . Perform routine advanced life support care as needed. Use proparacaine hydrochloride to assist eye irrigation ... . /Radioactives I, II, and III/

UsesMetallurgical tracer, cryochemistry, corrosion resistance, nuclear medicine.

OccurrenceTechnetium is the 76th most abundant element, but it is so rare that it is not found as astable element on Earth. All of it is artificially produced. Even though natural technetium isso scarce that it is considered not to exist on Earth, it has been identified in the light spectrumfrom stars. Using a spectroscope that produces unique lines for each element, scientists areable to view several types of stars. The resulting spectrographs indicate that technetium existsin the stars and thus the universe, but not on Earth as a stable element. It was the first new element to be produced artificially from another element experimentallyin a laboratory. Today, all technetium is produced mostly in the nuclear reactors of electricalgeneration power plants. Molybdenum-98 is bombarded with neutrons, which then becomesmolybdenum-99 when it captures a neutron. Since Mo-99 has a short half-life of about 66hours, it decays into Tc-99 by beta decay.

HistoryElement 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium. Technetium was actually discovered by Perrier and Segre in Italy in 1937. It was found in a sample of molybdenum that was bombarded by deuterons in the Berkeley cyclotron, and which E. Lawrence sent to these investigators. Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial materials have been made without success. If it does exist, the concentration must be very small. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars. Forty-three isotopes and isomers of technetium, with mass numbers ranging from 86 to 113, are known. 97Tc has a half-life of 2.6 × 106 years. Tc has a half-life of 4.2 × 106 years. The isomeric isotope 95mTc, with a half-life of 61 days, is useful for tracer work, as it produces energetic gamma rays. Technetium metal has been produced in kilogram quantities. The metal was first prepared by passing hydrogen gas at 1100°C over Tc2S7. It is now conveniently prepared by the reduction of ammonium pertechnetate with hydrogen. Technetium is a silvery-gray metal that tarnishes slowly in moist air. Until 1960, technetium was available only in small amounts and the price was as high as $2800/g, but the price is now of the order of $100/g. The chemistry of technetium is similar to that of rhenium. Technetium dissolves in nitric acid, aqua regia, and concentrated sulfuric acid, but is not soluble in hydrochloric acid of any strength. The element is a remarkable corrosion inhibitor for steel. It is reported that mild carbon steels may be effectively protected by as little as 55 ppm of KTcO4 in aerated distilled water at temperatures up to 250°C. This corrosion protection is limited to closed systems, since technetium is radioactive and must be confined. 99Tc has a specific activity of 6.2 × 108 Bq/g. Activity of this level must not be allowed to spread. 99Tc is a contamination hazard and should be handled in a glove box. The metal is an excellent superconductor at 11K and below.

UsesMinute quantities of TcO4- ion exert remarkable inhibition of the corrosion of soft iron in neutral aqueous solution: Cartledge, J. Am. Chem. Soc. 77, 2658 (1955).

UsesTechnetium is one of the few artificially produced elements that has practical industrial applications.One is that a very small amount (55-ppm) added to iron creates a corrosion-resistantalloy metal. This property is shared with many of the other transition metallic elements, but notwith other artificially produced elements that have higher atomic numbers and are radioactive.A radioisotope of technetium is widely used in nuclear medicine. The patient is injectedwith saline solution containing Tc-99m (the superscript “m” means that the isotope is unstableand that its nuclei holds more energy than the regular Tc-99 nuclei into which it decays). Thismeans that the Tc-99m will start to emit energy and will finally decay and change to the regularnuclei of Tc-99 when injected into the patient. This energy is in the form of very penetratinggamma rays (a strong type of X-rays). The radioactive solution of Tc-99m may be combinedwith other elements that are absorbed by certain organs of the human body being diagnosedor treated. For instance, adding tin to the solution targets the red blood cells, whereas phosphorusin the solution concentrates the radioactive solution in heat muscles. The gamma raysare strong enough to expose an X-ray film that depicts the internal image of the organ underexamination. This procedure is safe because Tc-99m has a half-life of only 6.015 hours, andthe Tc-99 has a half-life of over 200,000 years. However, the radioactivity will be harmless inless than a day because the body rapidly eliminates the residual radioactive solution.Technetium is also used as an alloy metal to produce super-strong magnets that are supercooledto near absolute zero to improve their efficiency. Powerful magnets are used in imagingequipment and possibly in future magnetic driven trains. Its radioactivity makes it useful as atracer in the production of metals and tracing flowing fluids in pipelines.