Xenon, Xe-133

INDICATIONS AND USAGE Xenon Xe 133 Gas has been shown to be valuable for diagnostic inhalation studies for the evaluation of pulmonary function, for imaging the lungs and may also be applied to assessment of cerebral blood flow.

DOSAGE AND ADMINISTRATION Xenon Xe 133 Gas is administered by inhalation from a closed respirator system or spirometer. The final patient dose should be measured by a suitable radioactivity calibration system immediately prior to administration. The recommended activity range employed for inhalation by the average patient (70 kg) is: Pulmonary function including imaging: 74 to 1110 megabecquerels (2 to 30 millicuries) Cerebral blood flow: 370 to 1110 megabecquerels (10 to 30 millicuries) This may be administered as a bolus into the tubing near the patient's mouthpiece or mask after the completion of a tidal exhalation, or by rebreathing for a period of approximately 5 minutes of the Xenon Xe 133 gas in equilibrium with the air contained in the closed system at concentrations of the radionuclide that may vary from 37 to 222 megabecquerels (1.0 to 6.0 millicuries) per liter.

CONTRAINDICATIONS None known.

ADVERSE REACTIONS Adverse reactions specifically attributable to Xenon Xe 133 Gas have not been reported.

DESCRIPTION Xenon Xe 133 Gas is for diagnostic inhalation use only. It is supplied in vials containing either 370 or 740 megabecquerels (10 or 20 millicuries) of Xenon Xe 133 Gas in 2 milliliters of carrier xenon and atmospheric air. Xenon Xe 133 Gas is chemically and physiologically similar to elemental xenon, a non-radioactive gas which is physiologically inert except for anesthetic properties at high doses. Xenon Xe 133 is produced by fission of Uranium U 235. At the time of calibration, it contains no more than 0.3% Xenon Xe 133m, no more than 1.5% Xenon Xe 131m, no more than 0.06% Krypton Kr 85 and no more than 0.01% Iodine I 131, with no less than 99.9% total radioactivity as radioxenon. Table 1 shows the effect of time on radionuclidic composition. Table 1. Radionuclidic Composition Percent of Total Radioactivity Days % Xe-133 % Xe-133m % Xe-131m % Kr-85 % I-131 -5 >98.3 98.1 97.2 95.7 <0.02 <4.1 <0.37 <0.02

HOW SUPPLIED Xenon Xe 133 Gas is available in 2 milliliter vials with color-coded labels in 370 megabecquerel (10 millicurie; Catalog No. 097) and 740 megabecquerel (20 millicurie; Catalog No. 098) sizes. Both sizes are available in packages of 1, 3 and 5 vials, each with individual lead shielding.