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Technetium-99m (Tc-99m) can be readily detected in the body by medical equipment because it emits 140.5 keV gamma rays (these are about the same wavelength as emitted by conventional X-ray diagnostic equipment), and its half-life for gamma emission is six hours (meaning 94% of it decays to 99 Tc in 24 hours). Besides, it emits virtually no beta ...
The metastable technetium-99m (99m Tc) is a short-lived (half-life about 6 hours) nuclear isomer used in nuclear medicine, produced from molybdenum-99. It decays by isomeric transition to technetium-99, a desirable characteristic, since the very long half-life and type of decay of technetium-99 imposes little further radiation burden on the body.
97m Tc is the most stable, with a half-life of 91.0 days (0.097 MeV). [4] This is followed by 95m Tc (half-life: 61 days, 0.038 MeV) and 99m Tc (half-life: 6.04 hours, 0.143 MeV). 99m Tc only emits gamma rays, subsequently decaying to 99 Tc. [7] For isotopes lighter than 98 Tc, the primary decay mode is electron capture to isotopes of molybdenum.
The half-life of 99 Tc is far longer than its metastable isomer, so the ratio of 99 Tc to 99m Tc increases over time. Both isomers are carried out by the elution process and react equally well with the ligand, but the 99 Tc is an impurity useless to imaging (and cannot be separated).
Molybdenum-99 has a half-life of 67 hours, so short-lived technetium-99m (half-life: 6 hours), which results from its decay, is being constantly produced. [21] The soluble pertechnetate TcO − 4 can then be chemically extracted by elution using a saline solution. A drawback of this process is that it requires targets containing uranium-235 ...
99m Tc is a very versatile radioisotope, and is the most commonly used radioisotope tracer in medicine. It is easy to produce in a technetium-99m generator, by decay of 99 Mo. 99 Mo → 99m Tc + e − + ν e. The molybdenum isotope has a half-life of approximately 66 hours (2.75 days), so the generator has a useful life of about two weeks.
Most radiotracers for cholescintigraphy are metal complexes of iminodiacetic acid (IDA) with a radionuclide, usually technetium-99m. This metastable isotope has a half-life of 6 hours, so batches of radiotracer must be prepared as needed using a moly cow. A widely recognized trade name for the preparation kits is TechneScan.
In particular it is used to carry the 99m Tc isotope (half-life 6 hours) which is commonly used in nuclear medicine in several nuclear scanning procedures. Pertechnetate is poorly hydrated as [TcO 4 (H 2 O) n]-and [TcO 4 (H 2 O) n-m]-[H 3 O] + m (n = 1–50, m = 1–4) clusters that have been demonstrated by simulation with DFT.