VQ SCAN
(last reviewed 07/17/2023)
RADIOPHARMACEUTICAL:
- Ventilation DTPA aerosol
- Perfusion Tc-99m labeled macroaggregated albumin (MAA) IV
ADULT DOSE:
- Ventilation 35 mCi DTPA nebulizer
- Perfusion 5.5 mCi MAA IV
PATIENT PREP: NG tubes must be removed prior to ventilation
EQUIPMENT & ENERGY:
- Planar Imaging
Parameters
- Matrix 128 x 128
- Zoom 1.0
- Analyzer Tc-99m NMG
- Detector - both, configured at 90 degrees
- Patient position - supine
- Ventilation images acquired for 200k counts
- Perfusion images acquired for 600k counts
SCAN PROTOCOL:
- Clamp patient's nose, place ventilation tube in mouth
- If pt cannot follow breathing instructions, ok to use a tightly sealed face mask
- Turn O2 to 9 - 11 L
- Breathe deeply for 5 minutes
- Inhaled ventilation dose calculated by count rate on LPO and RPO view (physicist attached chart)
- Ventilation imaging should be reviewed for completeness prior to injection of MAA
- Inject patient with Tc-99m MAA IV and acquire images
VIEWS (ventilation and perfusion)
- Anterior
- Posterior
- R lateral
- L lateral
- RPO
- LPO
PROCESSING:
- Adjust acquired images for optimal viewing
- Label images
- Ventilation and perfusion images paired for comparison
- Send images PACS
INDICATIONS: Pulmonary embolism