What Are the Risks of a Lung Ventilation/Perfusion Scan?

Lung ventilation/perfusion (VQ) scans involve little risk for most people. The radioisotopes used for both tests expose you to a small amount of radiation. The amount of radiation in the gas and injection together are about the same as the amount a person is naturally exposed to in 1 year.

Although rare, the radioisotopes may cause an allergic reaction.

Radiation

The radiation from the radioisotopes used in VQ scans leaves the body after a few days.

Exposure to radiation is associated with a risk of cancer. However, it’s not known whether the amount of radiation from a VQ scan puts you at higher risk than the amount of radiation you’re naturally exposed to. 

You and your doctor will decide whether the benefits of a VQ scan outweigh any possible risks. Your doctor also will try to avoid ordering repeated VQ scans over a short period.

If you’re pregnant or breast-feeding, talk to your doctor about the risk of radiation related to this test. He or she will consider whether another test can be used instead.

Allergic Reaction

Very rarely the radioisotopes used in VQ scans can cause an allergic reaction. Hives or a rash may result. Medicines can relieve this reaction.