Technetium (
99mTc) tetrofosmin is a drug used in
nuclear medicine
Nuclear medicine or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is "radiology done inside out" because it records radiation emitting ...
cardiac imaging. It is sold under the brand name Myoview (
GE Healthcare
GE HealthCare is a subsidiary of American multinational conglomerate General Electric incorporated in New York and headquartered in Chicago, Illinois. As of 2017, it is a manufacturer and distributor of diagnostic imaging agents and radiopharma ...
). The
radioisotope,
technetium-99m
Technetium-99m (99mTc) is a metastable nuclear isomer of technetium-99 (itself an isotope of technetium), symbolized as 99mTc, that is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used medical ra ...
, is chelated by two 1,2-''bis''
i-(2-ethoxyethyl)phosphino
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine defic ...
thane
ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...
s which belong to the group of
diphosphines
Diphosphines, sometimes called bisphosphanes, are organophosphorus compounds most commonly used as bidentate phosphine ligands in inorganic and organometallic chemistry. They are identified by the presence of two phosphino groups linked by a backb ...
and which are referred to as tetrofosmin.
Tc-99m tetrofosmin is rapidly taken up by myocardial tissue and reaches its maximum level in approximately 5 minutes. About 66% of the total injected dose is excreted within 48 hours after injection (40% urine, 26% feces).
Tc-99m tetrofosmin is indicated for use in scintigraphic imaging of the myocardium under stress and rest conditions. It is used to determine areas of reversible ischemia and infarcted tissue in the heart. It is also indicated to detect changes in perfusion induced by pharmacologic stress (
adenosine
Adenosine ( symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9-glycosidic bond. Adenosine is one of the four nucleoside building ...
,
lexiscan,
dobutamine or
persantine
Dipyridamole (trademarked as Persantine and others) is a nucleoside transport inhibitor and a PDE3 inhibitor medication that inhibits blood clot formation when given chronically and causes blood vessel dilation when given at high doses over a s ...
) in patients with coronary artery disease. Its third indication is to assess left ventricular function (ejection fraction) in patients thought to have heart disease.
No contraindications are known for use of Tc-99m tetrofosmin, but care should be taken to constantly monitor the cardiac function in patients with known or suspected coronary artery disease.
Patients should be encouraged to void their bladders as soon as the images are gathered, and as often as possible after the tests to decrease their radiation doses, since the majority of elimination is renal.
The recommended dose of Tc-99m tetrofosmin is between 5 and 33 millicuries (185-1221 megabecquerels). For a two-dose stress/rest dosing, the typical dose is normally a 10 mCi dose, followed one to four hours later by a dose of 30 mCi. Imaging normally begins 15 minutes following injection.
References
External links
Myoview Prescribing Information Page
Radiopharmaceuticals
Technetium-99m
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