Search results
Results from the WOW.Com Content Network
99m Tc's half-life of 6.0058 hours is considerably longer (by 14 orders of magnitude, at least) than most nuclear isomers, though not unique. This is still a short half-life relative to many other known modes of radioactive decay and it is in the middle of the range of half lives for radiopharmaceuticals used for medical imaging.
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.
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).
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.
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.
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 ...
Conference foes No. 17 BYU and No. 23 Colorado will square off on Saturday night in the Alamo Bowl in San Antonio. The Cougars (10-2) and Buffaloes (9-3) once had their sights set on a Big 12 ...
The radioactive 99m Tc O − 4 anion is an important radiopharmaceutical for diagnostic use. The advantages to 99m Tc include its short half-life of 6 hours and the low radiation exposure to the patient, which allow a patient to be injected with activities of more than 30 millicuries. [3] Na[99m Tc O