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[1] [2] 129 Xe is a stable, naturally occurring isotope of xenon with 26.44% isotope abundance. It is one of two Xe isotopes, along with 131 Xe, that has non-zero spin, which allows for magnetic resonance. 129 Xe is used for MRI because its large electron cloud permits hyperpolarization and a wide range of chemical shifts
In terms of detecting ventilation defects, 129 Xe has a lower signal-to-noise ratio but is more sensitive to defects due to its higher density and lower diffusivity. [30] Currently, using a larger volume of 129 Xe (up to 1 liter per scan) can compensate for its decreased signal-to-noise ratio compared to 3He (usually 0.1-0.3 liters per scan).
Naturally occurring xenon (54 Xe) consists of seven stable isotopes and two very long-lived isotopes. Double electron capture has been observed in 124 Xe (half-life 1.8 ± 0.5(stat) ± 0.1(sys) × 10 22 years) [2] and double beta decay in 136 Xe (half-life 2.165 ± 0.016(stat) ± 0.059(sys) × 10 21 years), [7] which are among the longest measured half-lives of all nuclides.
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129 Xe was derived from the extinct nuclide of iodine, iodine-129 or 129 I (with a half-life of 15.7 Million years, or Myr), which can be used in iodine-xenon (I-Xe) dating. The production of 129 Xe stopped within about 100 Myr after the start of the Solar System because 129 I became extinct. [1]
Because of its scarcity, xenon is much more expensive than the lighter noble gases—approximate prices for the purchase of small quantities in Europe in 1999 were 10 €/L (=~€1.7/g) for xenon, 1 €/L (=~€0.27/g) for krypton, and 0.20 €/L (=~€0.22/g) for neon, [67] while the much more plentiful argon, which makes up over 1% by volume ...
Xenon-enhanced CT scanning is a method of computed tomography (CT scanning) used for neuroimaging in which the subject inhales xenon gas while CT images are made. [1] The method can be used to assess changes in cerebral blood flow in the period shortly after a traumatic brain injury , [ 1 ] or to detect or indicate the location of a stroke. [ 2 ]
Xenon-135 (135 Xe) is an unstable isotope of xenon with a half-life of about 9.2 hours. 135 Xe is a fission product of uranium and it is the most powerful known neutron -absorbing nuclear poison (2 million barns ; [ 1 ] up to 3 million barns [ 1 ] under reactor conditions [ 2 ] ), with a significant effect on nuclear reactor operation.