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the radionuclide most commonly used to image the body in nuclear medicine scans. It is preferred because of its short half-life and because the emitted photon has an appropriate energy for normal imaging techniques. The "m" indicates that this radionuclide is metastable. It is generated on site from a molybdenum source.


A radioactive isotope of technetium having a half-life of 6 hr, in which the “m” refers to the fact that it is a metastable isotope.. 99mTc is used in nuclear medicine for a wide variety of diagnostic tests and imaging studies, e.g., myocardial perfusion scans, bone scans, and V/Q scans..

technetium Tc 99m albumin aggregated injection

An injection of technetium-99m that has been aggregated with albumin. It is used intravenously to scan the lungs.

technetium Tc 99m hexamethylpropyleneamine oxime

Abbreviation: HMPAO
A radioactive tracer consisting of technetium-99m linked to hexamethylpropyleneamine oxime. It is used to make nuclear imaging scans of the brain, e.g., in the determination of brain death. Absence of uptake of the molecule by the brain is diagnostic of brain death.

technetium 99m (methoxyisonitrile) MIBI

A radioactive tracer consisting of technetium-99m linked to MIBI. It is used in nuclear medical imaging (e.g., in scintimammography) to identify cancerous breast masses. Other uses of technetium 99m MIBI include cardiac, parathyroid, and thyroid imaging.

technetium Tc 99m methylene diphosphonate

A radioactive tracer consisting of technetium-99m linked to methylene diphosphonate. It is used in nuclear medicine to obtain images of bone and bone diseases, e.g., fractures not seen on plain x-rays, malignancies, and osteomyelitis.

technetium Tc 99m RBC

A radioactive tracer consisting of technetium-99m linked to red blood cells. It is used in clinical medicine to evaluate occult bleeding, e.g., from the gastrointestinal tract, or the motion of the heart in gated blood pool imaging.
Synonym: red blood cell scan

technetium Tc 99m sestamibi

A radioactive tracer consisting of technetium-99m linked to sestamibi. It is used to image blood flow to the heart muscle, esp. when combined with exercise or pharmacological “stress” tests. In a heart with normal blood flow, the isotope should be taken up uniformly throughout the heart muscle. Decreased uptake by regions of the heart occurs when coronary artery blood flow to those regions is blocked, e.g., by atherosclerotic plaque. Synonym: sestamibi

technetium Tc 99m sulfur colloid

A radioactive tracer consisting of technetium-99m linked to sulfur colloid. It is used in nuclear medicine scans to make images of gastric emptying or of the lymph nodes, liver, and spleen.


a chemical element, atomic number 43, atomic weight 99, symbol Tc. See Table 6.

the most frequently used radioisotope in nuclear medicine, a gamma emitter having a half-life of 6.04 hours and a primary photon energy of 140 keV; symbol 99mTc.
Tc sulfur coated scintiscan see scintiscan.
References in periodicals archive ?
production of Mo-99, the parent isotope of Tc-99m, for more than 25 years.
M2 EQUITYBITES-February 9, 2018-NorthStar Medical Radioisotopes wins US FDA and NRC's approval for first domestic supply of medical isotope Tc-99m in diagnostic imaging
Tc-99m is used in roughly 80%1 of all nuclear medicine procedures worldwide, and Mallinckrodt is a significant US and global supplier of this radioisotope.
The Tc-99m ECD SPECT/ CT revealed evidence of a large area of moderately decreased radiotracer distribution involving the superior, medial, and inferior frontal cortices of the right cerebral hemisphere.
2 mL aliquots were taken out at 1h, 4h and 24h and analyzed by instant thin layer chromatography for determination of 99mTc- clarithromycin, hydrolyzed/reduced Tc-99m and free 99mTcO4-.
These patients underwent resting first adenosine Tc-99m sestamibi gated cardiac single photon emission computed tomography with or without exercise supplementation protocols.
Five minutes after injection of Tc-99m, continuous uptake was observed in the right mid-abdomen, consistents with Meckel's diverticulum [Figure 1]a, and computed tomography revealed a suspicious enhancing cystic structure at the ileum, which was also consistent with Meckel's diverticulum [Figure 1]b.
The country's 35 hospitals with nuclear medicine centers have to import Tc-99m at a high price, making medical procedures costly.
Gamma camera imaging of myocardium perfusion with either TI-201 or Tc-99m is widely used for the detection of coronary artery disease (CAD).
Increased Tc-99m colloid uptake in a liver lesion is specific for focal nodular hyperplasia.
Thyroid replacement therapy can interfere with the uptake of Tc-99m pertechnetate and therefore should be started as soon as the scan is completed.
Tc-99m metilendifosfonat (MDP) ile yapilan uc fazli kemik sintigrafisi normal olarak degerlendirildi (Resim 1 b) ve Tc-99m human immun globulin (HIG) sintigrafisinde enflamasyon gozlenmedi.