What is a VQ Test and What Is It For?

Nuclear scanning tests use a special camera to take pictures of certain tissues in the body after a radioactive tracer accumulates in the tissues to make them visible.Two types of lung scans will be done:

Ventilation scan (VQ Test)
During a ventilation scan, a tracer gas is inhaled into the lungs. Pictures from this scan can show areas of the lungs that are not receiving enough air or that retain too much air. For the ventilation scan, a mask will be placed over your mouth and nose. You will inhale the tracer gas through the mask by taking a deep breath and then holding it. The camera will start scanning for radiation released by the tracer and then will produce pictures of its distribution in your lungs. You may be asked to breathe the gas in and out through your mouth into a bag for several minutes. You may then be asked to hold your breath for short periods (about 10 seconds. The camera will be moved so your lungs can be viewed from other angles. You need to remain very still during the scans to avoid blurring the pictures.Afterward, the radioactive gas will clear from your lungs as you breathe. The ventilation scan takes about 30 minutes.

Perfusion scan
During a perfusion scan, the tracer is injected into a vein in the arm. It travels through the bloodstream and into the lungs. Pictures from this scan can show areas of the lungs that are not receiving enough blood. The tracer is absorbed in areas of the lung where the blood flow is normal. For the perfusion scan, the injection site on your arm will be cleaned and an elastic band will be p laced around your upper arm. Then a small amount of the radioactive tracer is injected, usually into a vein on the inside of your elbow. After the injection, the camera will start scanning for radiation released by the tracer and will produce pictures of its distribution in your lungs. The camera will be moved so your lungs can be viewed from other angles. You need to remain very still during the scans to avoid blurring the pictures. The perfusion scan takes about 30 minutes.