Technetium Radiochemistry

Technetium ( Tc) Apeitide. This new radiotracer is a synthetic peptide that binds to the GPlIb/Illa adhesion-molecule receptors found on activated platelets. This allows the detection of acute venous thrombosis and is Food and Drug Administration (FDA)-approvcd for detection of acute lower extremity deep venous thrombosis. A lyophilized preparation of 100 yug of bibapeitide in the presence of heat will split and then complex to 20 mCi Tc-99m pertechnetate. Images of area of concern arc acquired at 10 and 60 minutes. 

Technetium ( Tcj Bicisate Injection. A sterile colorless solution of bicisate is complexed with Tc-99m pertech-neuite after reduction with a stannous salt. The precise structure of the technetium complex is fN,N -ethylene-di-L-cy.steinato(3-) oxo Tc]technetium(V) diethyl ester. This radiopharmaceutical is a neutral and lipophilic complex that crosses the blotxl-brain barrier and is selectively retained in the brain. Therefore, this radiotracer is used as a brain-perfusion imaging agent. After intravenous injection of 20 mCi (740 MBq) of Tc-99m bicisate, about 5% of the injected dose is localized within the brain cells 5 minutes after injection and demonstrates rapid renal excretion (74% in 24 hours). This radiotracer is used clinically to evaluate dementia, stroke, lack of brain perfusion ( brain death ), cerebral vascular reserve, or risk of stroke (acetazolamide challenge. study) and to localize a seizure focus for surgical removal. 

Technetium (Tc-99m) Depreotide Injection. Technetium depreotide injection is a new radiolabeled synthetic 

The primsu7 clinical indication for this study is pos i acute cholecystitis. In acute cholecystitis, there is obstrux of the cystic duct leading to the gallbladder. The galIblaU i is not visualized becau.se the radiotracer cannot cnlu Some other clinical conditions that can be diagnosed byh 

I ji images are common bile duel obsnuclion. biliary leak, lion surgery, biliary aliesia. and a cholediK hal ey.sl. 

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Although there are a lot of publications on the chemistry of technetium [2-4] and transition-metal clusters [1,5-8], the chemistry of technetium clusters was insufficiently studied until the early eighties [1,2]. Nevertheless, the available scanty data on the compounds with Tc-Tc bonds inspired hope that interesting results would be obtained in the chemistry of technetium in general, in radiochemistry, and in the chemistry of transition-metal cluster compounds. The anticipated results were actually obtained [9-15] and the conclusion was drawn that technetium had a number of anomalous cluster-forming properties [9]. This review looks at the detailed studies of these properties and their interpretation in terms of electronic structure theory. 

Anders, E. The Radiochemistry of Technetium. Natural Academy of Sciences, National Research Council, 1960... 

One of the most important aspects of radiochemistry is to know the composition of the 99mTc radiopharmaceutical in the radiolabeled kit. A quick and accurate method would help radiochemists understand the fundamental coordination chemistry at the tracer (99mTc) level. Since the total technetium (99mTc and "Tc) concentration in the generator eluant is very low (10 8—10 6 M), it is impossible to use spectroscopic (IR, UV/vis, and NMR) methods to characterize 99mTc radiopharmaceuticals. Therefore, there is a growing need for a quick and accurate method to determine the composition of the radiopharmaceutical at the tracer level. 

Nuclear chemistry (radiochemistry) has now become a large and very important branch of science. Over four hundred radioactive isotopes have been made in the laboratory, whereas only about three hundred stable isotopes have been detected in nature. Three elements —technetium (43), astatine (85), and promethium (61), as well as some trans-uranium elements, seem not to occur in nature, and are available only as products of artificial transmutation. The use of radioactive isotopes as tracers has become a valuable technique in scientific and medical research. The controlled release of nuclear energy promises to lead us into a new world, in which the achievement of man is no longer limited by the supply of energy available to him. 

Beals, D.M., Determination of Technetium-99 in aqueous samples by isotope dilution inductively coupled plasma-mass spectrometry. Proceedings of 3rd Annual Conference on Nuclear and Radiochemistry, Vienna, Sept. 1992. 

In 1965, Richards and his collaborators at Brookhaven National Laboratories (N.Y.) have introduced the Mo/ Tc generator for clinical application (Richards 1966). This radionuclide system made technetium-99m available for clinical research and has stimulated the development of the first labeled compounds, which had a considerable impact on radiochemistry and nuclear medicine (Andros et al. 1965 Harper et al. 1966 McAfee et al. 1964a, b Stern et al. 1965, 1966). In the years to follow, diagnostic nuclear medicine procedures based on " Tc pharmaceuticals increased to approximately 85%. The reasons for this rapid growth were the ideal nuclear properties of techne-tium-99m, its availability worldwide as a radionuclide generator system, and the development of new labeling techniques. 

Anders E (1960) The radiochemistry of technetium, NAS-NS 3021. Natural Academy of Sciences, Washington, DC... 

Following the discovery of radioactivity and nuclear fission, and the development of techniques in radiochemistry, it became possible to fill the remaining few gaps in the periodic table. The last gap to be filled was that corresponding to element 43, which became known as technetium from the Greek techne, meaning artificial or manufactured. It was manufactured in the course of some radiochemical reactions that would not have been feasible before the advent of nuclear physics. Until recently, it was believed that this element did not occur naturally, but a reexamination of old evidence has now suggested that it does in fact occur naturally and that early reports of its discovery made in 1925 may have been unjustly discredited. ... 

Mahmood A, Jones AG. Technetium radiopharmaceuticals. In Welch MJ, Redvanly CS, eds. Handbook of Radiopharmaceuticals Radiochemistry and Applications. Chichester Wiley, 2003 323-362. 

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