Xenoview Dosage

2.1 Recommended Dosage

The recommended target dose of XENOVIEW for adults and pediatric patients aged 12 years and older is 75 mL to 100 mL Dose Equivalent (DE) of hyperpolarized xenon Xe 129 by oral inhalation of the entire contents of one XENOVIEW Dose Delivery Bag.

Each bag contains at least 75 mL DE of hyperpolarized xenon Xe 129 measured within 5 minutes of administration, in a volume of 250 mL to 750 mL total xenon with additional nitrogen, NF (99.999% purity) added to reach a total volume of 1,000 mL. The minimum DE for a dose of XENOVIEW is 75 mL with a recommended DE target range of 75 mL to 100 mL. DE of greater than 100 mL is acceptable.

DE is the volume (mL) of 100% hyperpolarized, 100% isotopically enriched xenon Xe 129 that would provide the equivalent total Xe 129 magnetization (or MRI signal). The HPX Polarization Measurement Station measures DE. DE is defined by the following formula:

DE = (total volume xenon gas) × (fraction of xenon Xe 129 isotopic enrichment in the xenon gas) × (fraction of hyperpolarization)

where the total volume of xenon gas is 250 mL to 750 mL, the fraction of xenon Xe 129 isotopic enrichment is > 80% and the mean fraction of hyperpolarization is no less than 38% to 54% at the completion of polarization of 250 mL of xenon gas.

For example, if 300 mL of total xenon gas with 83% enrichment of xenon Xe 129 is dispensed from the HPX Hyperpolarizer at 40% hyperpolarization:

DE = 300 mL × 0.83 × 0.40 = 99.6 mL

2.2 Preparation, Administration, and Image Acquisition

• Prepare hyperpolarized xenon Xe 129 in the HPX Hyperpolarizer from the Xenon Xe 129 Gas Blend and add Nitrogen, NF (99.999% purity) to fill the remaining volume in the XENOVIEW Dose Delivery Bag to 1,000 mL, according to the HPX Hyperpolarization System Operator’s Manual.
• Measure the volume and DE in the XENOVIEW Dose Delivery Bag using the HPX Polarization Measurement Station no more than 5 minutes prior to administration. The DE measurement should be at least 75 mL. Do not use and discard the dose of XENOVIEW if the volume is determined to be outside of the acceptable range or the DE is less than 75 mL.
• Administer dose within 5 minutes of DE measurement.
• Do not use and discard the dose of XENOVIEW 60 minutes after filling of Dose Delivery Bag.
• Administer XENOVIEW according to the directions provided in the HPX Hyperpolarization System Operator’s Manual, Administering XENOVIEW.
  
• Fit the patient with an FDA-cleared Xe 129 chest coil in accordance with the chest coil manufacturer’s instructions for use.
• Position the patient supine with arms either by their side or above their head. Perform conventional 1H localizer scan, position the desired Xe 129 slices, and prepare the Xe 129 scan.
• For patients on supplemental oxygen, withhold oxygen inhalation for two breaths prior to XENOVIEW inhalation, and resume oxygen inhalation immediately following the imaging breath hold.
• Attach the mouthpiece to the XENOVIEW Dose Delivery Bag.
• With the patient positioned in the MRI scanner, place the mouthpiece in the patient’s mouth and instruct the patient to completely inhale the contents of the XENOVIEW Dose Delivery Bag with a single inhalation.
• Instruct the patient to hold the inhaled breath (up to 15 seconds) during MR image acquisition.
• Once the patient has inhaled the full dose of XENOVIEW, begin MRI scanning immediately.
• Upon scan completion instruct the patient to breathe normally.
• If the image quality is insufficient or if the patient was not able to sufficiently inhale the contents of the XENOVIEW Dose Delivery Bag, the scan can be repeated with a new dose of XENOVIEW.

2.3 Image Display and Interpretation

Evaluation of lung ventilation is based on distribution of XENOVIEW in the lungs.