A pulmonary ventilation/perfusion scan is a pair of nuclear scan tests. These tests use inhaled and injected radioactive material (radioisotopes) to measure breathing (ventilation) and circulation (perfusion) in all areas of the lungs.

A pulmonary ventilation/perfusion scan is actually two tests. These tests may be performed separately or together.

During the perfusion scan, a health care provider injects radioactive albumin into the patient's vein. The patient is immediately placed on a movable table that is under the arm of a scanner. The machine scans the patient's lungs as blood flows through them to detect the location of the radioactive particles.

The ventilation scan is performed by scanning the lungs while the person inhales radioactive gas. With a mask over the nose and mouth, the patient breathes the gas while sitting or lying on the table beneath the scanner arm.

You do not need to fast, eat a special diet, or take any medications before the test.

A chest x-ray is usually performed prior to or following a ventilation and perfusion scan.

You will sign a consent form and wear a hospital gown or comfortable clothing that does not have metal fasteners.

The table may feel hard or cold. You may feel a sharp prick while the material is injected into the vein for the perfusion portion of the scan. The mask used during the ventilation scan may give you a claustrophobic feeling. You must lie still during scanning.

The radioisotope injection usually does not cause discomfort.