VQ Scan

The V/Q, or lung ventilation and perfusion scan uses a gamma camera and small amounts of radioactive tracer to take images of the air and blood supply to the lungs. Its most common use is to diagnose a suspected clot on the lung (pulmonary embolus).

Before your scan

What to bring

  • Your referral form
  • Any relevant previous imaging
  • Your Medicare card and any concession cards


A referral from your doctor or medical specialist, and an appointment is required for this examination.

If you are pregnant, breastfeeding, or caring for a small child on the appointment day, please notify us in advance to receive special instructions.

During your scan

What to expect during my procedure

When you attend your appointment at Lake Imaging you will be asked to answer a few safety questions, remove any jewellery, watches etc, then change into an examination gown.

The technologist will explain what is involved in the V/Q examination and position you for the scan, then ask you to practice the required breathing procedure.

There are two stages to the V/Q scan. The first involves breathing in a harmless gas containing trace radioactive elements through a tube, holding several breaths briefly, with a number of deep breaths to follow. A gamma camera will then begin to take scans, rotating slowly around your chest for 10 to 15 minutes. You may breathe normally during this sequence, but must try not move. You will experience no unusual sensations or discomfort from the scan.

In the second stage of the V/Q examination, which follows immediately, the technologist will inject a perfusion tracer into an arm vein. A second set of images will then be obtained which takes about 10 minutes.

The entire V/Q examination takes up to one hour to complete.

Risks and side effects

Nuclear medicine examinations are considered very safe with almost no reported adverse reactions attributable to the radiopharmaceuticals used in these examinations.

Nuclear Medicine studies require very small doses of gamma radiation and are only performed where the benefits of the examination are deemed to outweigh any potential risks. At Lake Imaging you can be assured that using the latest technology and with staff trained in radiation reduction techniques, radiation doses are kept as low as reasonably possible.

If you are worried or concerned about having a Nuclear Medicine study you should discuss this with your referring doctor or medical specialist before coming for your examination.

If you think you may be pregnant, please inform our Nuclear Medicine team before your examination.

For further information regarding radiation safety please visit:

Who will perform and report my examination

At Lake Imaging your examination will be carried out by a Nuclear Medicine Technologist who has a degree Medical Radiations and is accredited by the ANZSNM.

Your images will be reviewed along with your relevant medical history, and any other imaging, and be reported by our Nuclear Medicine credentialed radiologist or Nuclear Medicine physician (a medical doctor specialising in the interpretation of Nuclear Medicine studies).

After your scan

What to expect after my procedure

Radiation from the injected isotope diminishes to a very low level by the end of the procedure, and you are free to resume normal activities. If you are caring for a small child, or breastfeeding, we may ask you to take some minor precautions.

How do I receive my results?

If your results are needed urgently, or you have an appointment straight after your scan with your referring doctor or health care provider, Lake Imaging will arrange to have your results available immediately. Otherwise your referring doctor or health care provider will receive your report within 48 hours of your examination.

Please ensure that you make a follow up appointment with your referring doctor or health care provider to discuss your results.