Radioaerosol Tips

QA Programs for Uptake Probes and Well Counters

With the possible shortage of Xenon looming over our heads, many departments will be turning to radioaerosol imaging with Tc-99m DTPA for lung ventilation studies.  If you are only performing these studies during a shortage, you may be a little rusty in remembering some important tips that are useful when performing this procedure.

  • When using O2 from a tank, replace the tank if the remaining pressure drops to 25% of the O2 in the tank.  Oxygen regulators attached to these tanks, especially in the floating ball type, are often not well calibrated.
  • If using in house wall O2, have engineering check the pressure at the wall inlet to ensure you are getting the 40-45 psi needed for good particle spallation.  Be aware that pressures can drop at times if others are using the system.
  • Patients should not smoke for 24 hours prior to scan when possible.  Smoke particles in the lungs act as magnets for Tc-99m DTPA radioaerosol particles and may cause a mottling appearance in the scan.
  • Be aware that shallow breathers tend to get more upper airway depositions.  Try to have the patient take slow and controlled deep breaths.  If this can’t be done, then tidal breathing will assure the best peripheral distribution of the radioaerosol to the lungs.
  • Individual breathing times in patients may vary.  When using a face mask or a finer particle radioaerosol delivery system, more extended breathing times may be required.
  • Before attaching the nose clip, have the patient wipe the bridge of their nose with an alcohol prep pad to remove any oils from the skin.  This will help keep the nose clip from sliding off the nose.
  • Once the O2 air supply has been turned off, instruct the patient to take an additional four or five breaths to purge the system of any residual radioaerosol.


Please refer to the Biodex Radioaerosol Troubleshooting guide for additional tips.