Xenon Xe-133 Gas is supplied in a mixture of xenon gas (5%) in carbon dioxide (95%). It is contained within septum sealed glass vials and has been proven valuable in the diagnostic evaluation of pulmonary function and imaging of the lungs, as well as assessment of cerebral blood flow.
It is reactor-produced as a by-product of Uranium U235 fission. The contents of the vial are in gaseous form, contain no preservatives, and are ready for use. Xenon Xe-133 is chemically and physiologically related to elemental Xenon, a non-radioactive monoatomic gas, which is physiologically inert except for anesthetic properties at high doses. The vial stopper contains dry natural rubber latex and may cause allergic reactions in providers or patients who are sensitive to latex.
Xenon-133 is a readily diffusible gas which is neither utilized nor produced by the body. It passes through cell membranes and freely exchanges between blood and tissue. It tends to concentrate more in body fat than in blood, plasma, water or protein solutions. In the concentrations used for diagnostic purposes it is physiologically inactive. Inhaled Xenon Xe-133 Gas will enter the alveolar wall and enter the pulmonary venous circulation via the capillaries. Most of the Xenon Xe-133 that enters the circulation from a single breath is returned to the lungs and exhaled after a single pass through the peripheral circulation. There are no known contraindications.
The gas adheres to some plastics and rubber and should not be used in tubing or respirator containers. The unrecognized loss of radioactivity from the dose for administration may render the study non-diagnostic. Because Xenon gas is heavier than air, escaped xenon pools at floor level. The room should be well ventilated, and some states still require a negative pressure flow.
Gas delivery systems used for dispensing Xenon gas consist of a shielded spirometer, oxygen delivery system and a xenon charcoal trap, to capture the exhaled Xenon. Delivery systems must be leak proof to avoid loss of radioactivity into environments not specifically protected by exhaust systems. These delivery systems should also protect the technologist from radiation exposure.
References:
Xenon Xe-133 Gas Prescribing Information; Lantheus Medical Imaging website; Accessed March 28th, 2014: http://www.lantheus.com/PDF/pi/Xenon%20Booklet%20Label%20515083-0811%20(Booklet)%209-20-2011.pdf .
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