Tetrofosmin
Encyclopedia
Technetium tetrofosmin is a drug used in nuclear medicine
cardiac imaging. It is sold under the brand name Myoview (GE Healthcare
). The radioisotope, technetium-99m
, is chelated by two 1,2-bis[di-(2-ethoxyethyl)phosphino]ethane ligand
s which belong to the group of diphosphines
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. 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) in patients with coronary artery disease. Its third indication is to assess left ventricular function (ejection fraction) in patients thought to have heart disease.
There are no known contraindications 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 bladder as soon as the images are gathered, and as often as possible after the exam to decrease their radiation dose, since the majority of elimination is renal.
The recommended dose of Tc-99m tetrofosmin is between 5-33 millicuries (185-1221 megabecquerels). For a two dose stress/rest dosing, the typical dose is normally a 10 mCi dose, followed 1 to 4 hours later by a dose of 30 mCi. Imaging normally begins 15 minutes following injection.
Nuclear medicine
In nuclear medicine procedures, elemental radionuclides are combined with other elements to form chemical compounds, or else combined with existing pharmaceutical compounds, to form radiopharmaceuticals. These radiopharmaceuticals, once administered to the patient, can localize to specific organs...
cardiac imaging. It is sold under the brand name Myoview (GE Healthcare
GE Healthcare
GE Healthcare is a division of GE Technology Infrastructure, which is itself a division of General Electric . It employs more than 46,000 people worldwide and is headquartered in Little Chalfont, Buckinghamshire, United Kingdom. GE Healthcare is the first GE business segment to be headquartered...
). The radioisotope, technetium-99m
Technetium-99m
Technetium-99m is a metastable nuclear isomer of technetium-99, symbolized as 99mTc. The "m" indicates that this is a metastable nuclear isomer, i.e., that its half-life of 6 hours is considerably longer than most nuclear isomers that undergo gamma decay...
, is chelated by two 1,2-bis[di-(2-ethoxyethyl)phosphino]ethane ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...
s which belong to the group of diphosphines
Diphosphines
Diphosphines, sometimes called bisphosphanes are organophosphorus compounds that are used as ligands in inorganic and organometallic chemistry. They are identified by the presence of two phosphino groups linked by a backbone and are usually chelating...
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. 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) in patients with coronary artery disease. Its third indication is to assess left ventricular function (ejection fraction) in patients thought to have heart disease.
There are no known contraindications 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 bladder as soon as the images are gathered, and as often as possible after the exam to decrease their radiation dose, since the majority of elimination is renal.
The recommended dose of Tc-99m tetrofosmin is between 5-33 millicuries (185-1221 megabecquerels). For a two dose stress/rest dosing, the typical dose is normally a 10 mCi dose, followed 1 to 4 hours later by a dose of 30 mCi. Imaging normally begins 15 minutes following injection.