Xenon - Xenon Xe-133 gas prescribing information
INDICATIONS AND USAGE:
Inhalation of Xenon Xe 133 Gas has proved valuable for the evaluation of pulmonary function and for imaging the lungs. It may also be applied to assessment of cerebral flow.
DOSAGE AND ADMINISTRATION:
Xenon Xe 133 Gas is administered by inhalation from closed respirator systems or spirometers.
The suggested activity range employed for inhalation by the average adult patient (70 kg) is:
Pulmonary function including imaging: 74-1110MBq (2-30mCi) in 3 liters of air.
Cerebral blood flow: 370-1110MBq (10-30mCi) in 3 liters of air.
The patient dose should be measured by a suitable radioactivity calibration system immediately prior to administration.
RADIATION DOSIMETRY
The estimated absorbed radiation doses Method of Calculation: A Schema for Absorbed-Dose Calculation for Biologically Distributed Radionuclides, Supplement No. 1, MIRD pamphlet No. 1, J. Nucl. Med., p.7 (1968). to an average patient (70 kg) for pulmonary perfusion and cerebral blood flow studies from a maximum dose of 1110 MBq (30mCi) of Xenon Xe 133 in 3 liters of air are shown in Table 4.
| Effective | Whole | |||
|---|---|---|---|---|
| Half-Time | Lungs 99% of activity is in lungs. | Brain | Body | |
| mGy/1110MBq | (rads/30mCi) | |||
| Pulmonary Perfusion | 2 min. | 2.5(0.25) | 0.014(0.0014) | 0.027(0.0027) |
| Cerebral Blood Flow | 5 min. | 6.3(0.63) | 0.035(0.0035) | 0.068(0.0068) |
CONTRAINDICATIONS:
None known.
ADVERSE REACTIONS:
Adverse reactions related to the use of this agent have not been reported to date.
DESCRIPTION:
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 is suitable for inhalation in the diagnostic evaluation of pulmonary function and imaging, as well as assessment of cerebral blood flow. Xenon Xe 133 Gas is reactor-produced as a by-product of Uranium U235 fission. Each vial contains the labeled amount of Xenon Xe 133 radioactivity at the time of calibration. 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.
PHYSICAL CHARACTERISTICS
Xenon Xe 133 decays by beta and gamma emissions with a half-life of 5.245 days. Kocher, David C., "Radioactive Decay Data Tables," DOE/TIC-11026, p. 138,1981. Significant radiations which are emitted by the nuclide are listed in Table 1.
| Mean | Mean % per | |
|---|---|---|
| Radiation | Energy (KeV) | Disintegration |
| Beta-2 | 100.6 | 99.3 |
| Ce-K-2 | 45.0 | 53.3 |
| Ce-L-2 | 75.3 | 8.1 |
| Ce-M-2 | 79.8 | 1.7 |
| Gamma-2 | 81.0 | 36.5 |
| K α2 X-ray | 30.6 | 13.6 |
| K α1 X-ray | 31.0 | 25.3 |
| K β X-ray | 35.0 | 9.1 |
EXTERNAL RADIATION
The specific gamma ray constant for Xenon Xe 133 is 3.6 microcoulombs/Kg-MBq-hr (0.51R/hr-mCi) at 1 cm. The first half value thickness of lead is 0.0035 cm. A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from the interposition of various thicknesses of Pb is shown in Table 2. For example, the use of 0.20 cm of Pb will decrease the external radiation exposure by a factor of 1,000.
| cm of Pb | Radiation Attenuation Factor |
|---|---|
| 0.0035 | 0.5 |
| 0.037 | 10 -1 |
| 0.12 | 10 -2 |
| 0.20 | 10 -3 |
| 0.29 | 10 -4 |
To correct for physical decay of this radionuclide, the fractions that remain at selected time intervals after the time of calibration are shown in Table 3.
| Fraction | Fraction | ||
|---|---|---|---|
| Day | Remaining | Day | Remaining |
| 0 Calibration Day | 1.000 | 8 | .349 |
| 1 | .877 | 9 | .302 |
| 2 | .768 | 10 | .268 |
| 3 | .674 | 11 | .235 |
| 4 | .591 | 12 | .206 |
| 5 | .518 | 13 | .181 |
| 6 | .452 | 14 | .157 |
| 7 | .398 |
CLINICAL PHARMACOLOGY:
Xenon Xe 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.
HOW SUPPLIED:
The Xenon Xe 133 Gas is supplied as part of the Calidose™ system, consisting of 3ml unit dose vials and the Calidose™ dispenser for shielded dispensing.
Normally vials containing either 370 or 740MBq (10 or 20mCi)/vial, packed 1 vial or 5 vials per shield tube, are supplied.
The NDC number for: 10mCi vial is 11994-127; 20mCi vial is 11994-128.
Store at room temperature.
This radiopharmaceutical is approved for distribution to persons licensed pursuant to the Code of Massachusetts Regulations 105 CMR 120.100 for the uses listed in 105 CMR 120. 547 or 120.552 or under equivalent regulations of the U.S. Nuclear Regulatory Commission, an Agreement State, or a Licensing State.
The contents of the vial are radioactive. Adequate shielding and handling precautions must be maintained.
Lantheus Medical Imaging, Inc.
331 Treble Cove Rd., N. Billerica, MA 01862 USA For Ordering Tel. Toll Free 800-299-3431 (For Massachusetts & International, Call 978-667-9531) All Other Business 800-362-2668 Patent: http://www.lantheus.com/patents/index.html
Printed in U.S.A.
515083-0719 July 2019
