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Journal of Labelled Compounds &... Sep 2017Technetium-99m ( Tc) is a widely used radionuclide, and the development of Tc imaging agents continues to be in demand. This overview discusses basic principles of Tc... (Review)
Review
Technetium-99m ( Tc) is a widely used radionuclide, and the development of Tc imaging agents continues to be in demand. This overview discusses basic principles of Tc radiopharmaceutical preparation and design and focuses on the Tc radiochemistry relevant to its pharmaceutical applications. The Tc complexes are described based on the most typical examples in each category, keeping up with the state-of-the-art in the field. In addition, the main current strategies to develop targeted Tc radiopharmaceuticals are summarized.
Topics: Animals; Diagnostic Imaging; Humans; Radiochemistry; Radiopharmaceuticals; Staining and Labeling; Technetium
PubMed: 28618064
DOI: 10.1002/jlcr.3531 -
Current Pharmaceutical Design 2018Technetium (99mTc)-radiolabeled colloids are popular tracers used to map lymphatic vessels and regional lymph nodes (LNs). The regional LN status is a significant... (Review)
Review
Technetium (99mTc)-radiolabeled colloids are popular tracers used to map lymphatic vessels and regional lymph nodes (LNs). The regional LN status is a significant determinant of cancer stage and patient prognosis, and strongly influences treatment. Regional LN dissection has become a part of surgical treatment. However, not all patients with LN involvement benefit from extensive lymphadenectomy in terms of prolonged survival. Moreover, overtreatment of patients with localized disease carries the unnecessary risk of complications. It is believed that sentinel LN biopsy (SLNB) allows to assess the involvement of the most representative LN of the lymphatic basin and to decide on radical LN dissection.99mTc is an easily available radionuclide emitting gamma rays. The value of 99mTc for diagnostic procedures is associated with its relatively short half-life that makes it safe both for patients and medical personnel. A colloid presenting specific physical and biological properties, including optimal particle size, is a carrier for the radionuclide. When administered at the tumor site, a radiocolloid is absorbed by the lymphatics, and the first LN that it gets trapped in is referred to as the sentinel LN (SLN). The radiopharmaceutical must reach the SLN relatively quickly, but its storage within the SLN, and the radionuclide's half-life must be long enough to enable intraoperative imaging and evaluation. SLNB is currently the gold standard in breast cancer and malignant melanoma diagnosis, and is under extensive investigation in gynecological cancers. Here, we provide a historical perspective of the SLN concept and the clinical relevance of SLNB in gynecologic oncology. Moreover, we review the technical aspects of the application of 99mTc-based radiopharmaceuticals in lymphoscintigraphy and intraoperative lymphatic mapping.
Topics: Breast Neoplasms; Female; Humans; Particle Size; Radiopharmaceuticals; Sentinel Lymph Node Biopsy; Surface Properties; Technetium
PubMed: 29766779
DOI: 10.2174/1381612824666180515122150 -
Journal of the American College of... May 2017
Topics: Humans; Molybdenum; Radioisotopes; Radiopharmaceuticals; Technetium; United States
PubMed: 28381357
DOI: 10.1016/j.jacr.2017.02.007 -
European Journal of Nuclear Medicine Mar 1996The history of the discovery of technetium is reviewed within the framework of the discovery and production of artificial radioactivity in the twentieth century.... (Review)
Review
The history of the discovery of technetium is reviewed within the framework of the discovery and production of artificial radioactivity in the twentieth century. Important elements of this history are the accidental production of this element in a cyclotron in Berkeley, California, USA, a machine devised by Ernest Orlando Lawrence, and its subsequent discovery in 1937 by Carlo Perrier and Emilio Segrè in scrap metal parts sent by Lawrence to Palermo, Italy by mail. A detailed account is given of the steps taken; the history of the later discovery of the technetium-99m isotope in 1938 is likewise examined. Sources of natural and artificial technetium are briefly discussed.
Topics: Cyclotrons; History, 20th Century; Technetium
PubMed: 8599967
DOI: 10.1007/BF00837634 -
Current Radiopharmaceuticals Apr 2011This review gives a survey on the use and applications of technetium-94m ((94m)Tc) as a non-conventional positron emission tomography (PET) radionuclide for molecular... (Review)
Review
This review gives a survey on the use and applications of technetium-94m ((94m)Tc) as a non-conventional positron emission tomography (PET) radionuclide for molecular imaging. The first part of this review describes the production and processing of (94m)Tc. The second part covers basic concepts of technetium coordination chemistry with a special focus on the synthesis of (94m)Tc-labeled compounds for molecular imaging purposes. The review concludes with a summary and an outlook on the prospects of using (94m)Tc in the field of PET chemistry and molecular imaging.
Topics: Humans; Isotopes; Positron-Emission Tomography; Radiopharmaceuticals; Technetium
PubMed: 22191648
DOI: 10.2174/1874471011104020090 -
Journal of Labelled Compounds &... Apr 2014The rich coordination chemistry of (99m) Tc distinguishes this radiometal from other radiolabels applied for single-photon emission computed tomography (SPECT) or... (Review)
Review
The rich coordination chemistry of (99m) Tc distinguishes this radiometal from other radiolabels applied for single-photon emission computed tomography (SPECT) or positron emission tomography (PET). This potential should be used to create novel opportunities for the development of effective imaging probes. In this context, the field of high-valent technetium chemistry has received much interest. It has been shown that fac-{(99m) TcO3 }(+) complexes are potential new synthons for radiopharmaceutical developments, due to their unique physicochemical properties and unprecedented reactivity. In this article, recent developments and the 'state of the art' in this field of technetium chemistry will be reviewed comprehensively.
Topics: Drug Discovery; Radiochemistry; Radiopharmaceuticals; Technetium
PubMed: 24347394
DOI: 10.1002/jlcr.3148 -
Environmental Science & Technology Mar 2023The chemistry of technetium ((Tc) = 2.11 × 10 years) is of particular importance in the context of nuclear waste disposal and historic contaminated sites....
The chemistry of technetium ((Tc) = 2.11 × 10 years) is of particular importance in the context of nuclear waste disposal and historic contaminated sites. Polycarboxylate ligands may be present in some sites and are potentially capable of strong complexing interactions, thus increasing the solubility and mobility of Tc under environmentally relevant conditions. This work aimed to determine the impact of five organic complexing ligands [L = oxalate, phthalate, citrate, nitrilotriacetate (NTA), and ethylenediaminetetraacetate (EDTA)] under anoxic, alkaline conditions (pH ≈ 9-13) on the solubility of technetium. X-ray absorption spectroscopy confirmed that TcO(am,hyd) remained the solubility-controlling solid phase in undersaturation solubility experiments. Ligands with maximum coordination numbers (CN) ≥ 3 (EDTA, NTA, and citrate) exhibited an increase in solubility from pH 9 to 11, while ligands with CN ≤ 2 (oxalate and phthalate) at all investigated pH and CN ≥ 3 at pH ≈ 13 were outcompeted by hydrolysis reactions. Though most available thermodynamic values were determined under acidic conditions, these models satisfactorily explained high-pH undersaturation solubility of technetium for citrate and NTA, whereas experimental data for Tc(IV)-EDTA were highly overestimated. This work illustrates the predominance of hydrolysis under hyperalkaline conditions and provides experimental support for existing thermodynamic models of Tc-L except Tc-EDTA, which requires further research regarding aqueous speciation and solubility.
Topics: Edetic Acid; Technetium; Solubility; Ligands; Carboxylic Acids; Citrates; Oxidation-Reduction
PubMed: 36827231
DOI: 10.1021/acs.est.2c09360 -
Revista Espanola de Medicina Nuclear 1998Nowadays, labelled polyclonal and monoclonal antibodies are widely used for immunoscintigraphic diagnosis of different diseases. Technetium-99m is often considered to be... (Review)
Review
Nowadays, labelled polyclonal and monoclonal antibodies are widely used for immunoscintigraphic diagnosis of different diseases. Technetium-99m is often considered to be the label of choice for radioimmunodiagnosis for reasons of cost, availability and imaging properties, in spite of its relatively short physical half-life (6.01 h). The existing labelling methods may be classified into two types: direct approaches, in which disulphide bridges within are reduced to generate endogenous sulfhydryl groups able to efficiently bind technetium due to their strong chelating capacity and indirect methods, in which an exogenous chelator is covalently attached to the protein to serve as the binding site. All these procedures have their advantages and drawbacks. There is no consensus among the authors about which of the methods is the best. The employed approach depends on the particular situation. The aim of the present work is to show an update about the available procedures for 99mTc-labelling of antibodies and its fragments.
Topics: Antibodies; Avidin; Biotinylation; Chelating Agents; Immunoglobulin Fragments; Isotope Labeling; Oxidation-Reduction; Pentetic Acid; Photochemistry; Reducing Agents; Sulfhydryl Compounds; Sulfhydryl Reagents; Technetium; Tin; beta-Aminoethyl Isothiourea
PubMed: 9721347
DOI: No ID Found -
Chemical Reviews May 2010
Comparative Study Review
Topics: Animals; Drug Design; Gallium; Humans; Molecular Imaging; Radiopharmaceuticals; Technetium
PubMed: 20415476
DOI: 10.1021/cr1000755 -
Nature Chemistry Jul 2009
Topics: Humans; Pressure; Radiation Monitoring; Radioactivity; Technetium; Temperature
PubMed: 21378873
DOI: 10.1038/nchem.271