technetium-99m
Also known as Tc-99m, 99mTc
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 radioisotope in the world.
Key facts
- Isotope.symbol
- Tc
- Isotope.mass_number
- 99m
- Isotope.mass
- 98.9063
- Isotope.num_neutrons
- 56
- Isotope.num_protons
- 43
- Isotope.image
- First technetium-99m generator - 1958.jpg
- Isotope.image_caption
- The first technetium-99m generator, 1958.A 99mTc pertechnetate solution isbeing eluted from 99Mo molybdatebound to a chromatographic substrate
- Isotope.decay_product
- Technetium-99
- Isotope.decay_symbol
- Tc
- Isotope.decay_mass
- 99
- Isotope.decay_mode1
- Isomeric transition
- Isotope.decay_energy1
- 0.1405 (99%)
~31 min read
Article
37 sectionsContents
- History
- Discovery
- Early medical applications in the United States
- Worldwide expansion
- Americas
- Oceania
- Europe
- Shortage
- Nuclear properties
- Production
- Production of <sup>99</sup>Mo in nuclear reactors
- Neutron irradiation of uranium-235 targets
- Neutron activation of <sup>98</sup>Mo
- Production of <sup>99m</sup>Tc/<sup>99</sup>Mo in particle accelerators
- Production of "Instant" <sup>99m</sup>Tc
- Indirect routes of production of <sup>99</sup>Mo
- Technetium-99m generators
- Preparation
- Medical uses
- Radiation side-effects
- 3-D scanning technique: SPECT
- Bone scan
- Myocardial perfusion imaging
- Cardiac ventriculography
- Functional brain imaging
- Sentinel-node identification
- Immunoscintigraphy
- Blood pool labeling
- Pyrophosphate for heart damage
- Sulfur colloid for spleen scan
- Meckel's diverticulum
- Pulmonary
- See also
- Notes
- References
- Further reading
- External links
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 radioisotope in the world.
Technetium-99m is used as a radioactive tracer and can be detected in the body by medical equipment (gamma cameras). It is well suited to the role, because it emits readily detectable gamma rays with a photon energy of 140.5 keV (within the range emitted by conventional X-ray diagnostic equipment) and its half-life is 6.0066 hours (meaning 93.7% of it decays to 99Tc in 24 hours). The relatively short physical half-life of the isotope and its biological half-life of 1 day (in terms of human activity and metabolism) allows for scanning procedures which collect data rapidly but keep total patient radiation exposure low. The same characteristics make the isotope unsuitable for therapeutic use because Technetium-99m emits penetrating gamma rays and decays quickly, so it cannot deliver a strong, localized dose to destroy diseased tissue.
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