The first artificially produced element and a radioactive fission product of URANIUM. Technetium has the atomic symbol Tc, atomic number 43, and atomic weight 98.91. All technetium isotopes are radioactive. Technetium 99m (m=metastable) which is the decay product of Molybdenum 99, has a half-life of about 6 hours and is used diagnostically as a radioactive imaging agent. Technetium 99 which is a decay product of technetium 99m, has a half-life of 210,000 years.
Technetium Tc 99m Sulfur Colloid
A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in the gastrointestinal system, liver, and spleen.
Organic compounds that contain technetium as an integral part of the molecule. These compounds are often used as radionuclide imaging agents.
Technetium Tc 99m Medronate
A gamma-emitting radionuclide imaging agent used primarily in skeletal scintigraphy. Because of its absorption by a variety of tumors, it is useful for the detection of neoplasms.
Technetium Tc 99m Sestamibi
A technetium imaging agent used to reveal blood-starved cardiac tissue during a heart attack.
Technetium Tc 99m Exametazime
A gamma-emitting RADIONUCLIDE IMAGING agent used in the evaluation of regional cerebral blood flow and in non-invasive dynamic biodistribution studies and MYOCARDIAL PERFUSION IMAGING. It has also been used to label leukocytes in the investigation of INFLAMMATORY BOWEL DISEASES.
Technetium Tc 99m Aggregated Albumin
A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in cardiovascular and cerebral circulation.
Technetium Tc 99m Pentetate
The production of an image obtained by cameras that detect the radioactive emissions of an injected radionuclide as it has distributed differentially throughout tissues in the body. The image obtained from a moving detector is called a scan, while the image obtained from a stationary camera device is called a scintiphotograph.
Sodium Pertechnetate Tc 99m
A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in the gastrointestinal system, cardiovascular and cerebral circulation, brain, thyroid, and joints.
Technetium Tc 99m Dimercaptosuccinic Acid
Pathologic inclusions occurring in erythrocytes.
Poly or pyrophosphates of tin. In conjunction with radioactive technetium these compounds are used as bone-scanning agents and in scintigraphy to diagnose myocardial and cerebral infarction.
Technetium Tc 99m Diethyl-iminodiacetic Acid
Inorganic compounds that contain tin as an integral part of the molecule.
Technetium Tc 99m Lidofenin
A nontoxic radiopharmaceutical that is used in RADIONUCLIDE IMAGING for the clinical evaluation of hepatobiliary disorders in humans.
Tomography, Emission-Computed, Single-Photon
A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.
Technetium Tc 99m Disofenin
Technetium Tc 99m Pyrophosphate
A radionuclide imaging agent used primarily in scintigraphy or tomography of the heart to evaluate the extent of the necrotic myocardial process. It has also been used in noninvasive tests for the distribution of organ involvement in different types of amyloidosis and for the evaluation of muscle necrosis in the extremities.
Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.
Sentinel Lymph Node Biopsy
Sensitivity and Specificity
Evaluation Studies as Topic
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Predictive Value of Tests
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).