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VQ Lung Scan


  • You have been referred for a VQ Lung scan (Ventilation-Perfusion Quotient) in which you have two sets of images done:  Ventilation images and Perfusion images.

  • Ventilation images shows the ability of air to reach all parts of the lungs.

  • Perfusion images shows how well blood circulates within the lungs.

  • A VQ Lung scan is very sensitive in detecting blood clots in the lung (or pulmonary embolism).

  • To perform the ventilation study, you breath in a specially produced radioactive gas (Technegas).

  • There is no taste to this gas and is extremely safe to inhale.

  • You then lay still on a bed whilst a Gamma Camera (1) rotates around your chest and images your lungs (Ventilation Phase). This takes approximately 10 minutes to complete.

  • You then have a small injection of 99mTc-MAA (99m-Technetium Micro Aggregated Albumin). This allows us to image the blood flow to your lungs.

  • There are rarely any side effects with this injection.

  • We then repeat taking images of your lungs (Perfusion phase). This takes approximately 8 minutes to complete.

  • You receive a slight radiation dose by having a VQ Lung Scan with SPECT/CT ~ up to 1.17 times your yearly background radiation (2).


Patient Preparation:

  • If you are pregnant, trying to fall pregnant or breast feeding, you must inform our staff.

  • If you have had prior imaging e.g. PET, Nuclear Scan, CT, MRI, X-Ray, Ultrasound, etc... please bring these with you.

  • Please also bring your referral and any blood results that you may have had done.

  • There is no preparation for a VQ Lung Scan.

  • If you are on any medications, please take these as normal.

  • Wear comfortable clothing and minimise the amount of metal jewellery you have on (all metal objects will need to be removed prior to imaging).

  • Important Note: You cannot have this test if you have had a PET or Nuclear Scan within 24 hours prior to this test. If you have had Iodine-131 therapy, allow 4-weeks before having this test. Please ring to discuss booking options.​


Breast-Feeding Mothers: Once you have been given the 99mTc-MAA tracer, you need to stop breast-feeding for 13-hours. During this time, you need to express and discard your breast milk as often as required. You will need to bottle-feed your child during this period.


(1) A Gamma Camera is a device that detects gamma-rays (gamma-rays are very similar to x-rays) and does not emit any radiation.

(2) We all receive a yearly background radiation dose ~ 2.4mSv. VQ Lung Scan with SPECT ~ 2.8mSv = 1.166 times yearly background dose.

value. quality care. convenience.

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