How It Is Done
You will need to take off any jewelry that might interfere with the scan. You may need to take off all or most of your clothes, depending on which area is being examined. You will be given a cloth or paper covering to use during the test.
During the scan, you might lie on your back with the scanning camera over or under your chest. Or you might sit with the camera next to your chest. The camera does not produce any radiation.
Ventilation scan
For the ventilation scan, a mask will be placed over your mouth and nose. Or you may have a nose clip on your nose and a tube in your mouth that you use for breathing. You will take a deep breath and hold it.
The camera will take pictures as the tracer moves through your lungs.
You may be asked to breathe the gas in and out through your mouth for several minutes. You may then be asked to hold your breath for short periods (about 10 seconds) and to change positions. This is done so your lungs can be viewed from other angles. The camera may move to take pictures from different angles. You need to stay very still during the scans to avoid blurring the pictures.
Afterward, the radioactive gas or mist will clear from your lungs as you breathe.
Perfusion scan
For the perfusion scan, a small amount of the radioactive tracer is injected into your arm.
After the tracer is injected, the camera will take pictures as the tracer moves through your lungs. The camera may be repositioned around your chest to get different views. You need to stay very still during the scans to avoid blurring the pictures.
How long the test takes
The two scans are usually done together and will take about an hour. The ventilation scan takes about 15 to 30 minutes, and the perfusion scan takes about 5 to 10 minutes. The scans can be done on their own.