The ventilation scan usually is done first. A chest X-ray is usually done the same day, either before or after the lung scan. Talk to your doctor if you have any concerns about the need for the test, its risks, how it will be done, or what the results will mean.
To help you understand the importance of this test, fill out the medical test information form. You will need to take off any jewellery 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. 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. The ventilation scan takes about 15 to 30 minutes. 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. The perfusion scan takes about 5 to 10 minutes. Breathing through the mask during the ventilation scan may be uncomfortable, especially if you feel very short of breath. But you will be given plenty of oxygen through the mask.
If you have a perfusion scan, you may feel nothing at all from the needle, or you may feel a brief sting or pinch. Otherwise, a lung scan is usually painless.
You may find it hard to stay still. Ask for a pillow or blanket to make yourself as comfortable as possible before the scan begins. Allergic reactions to the radioactive tracer are very rare. Some people have soreness or swelling at the injection site. A moist, warm compress applied to the arm may help.
Anytime you're exposed to radiation, there's a small chance of damage to cells or tissue. That's the case even with the low-level radioactive tracer used for this test. But the chance of damage is very low compared with the benefits of the test. Most of the tracer will leave your body through your urine or stool within a day. So be sure to flush the toilet right after you use it, and wash your hands well with soap and water.
The amount of radiation in the tracer is very small. This means it isn't a risk for people to be around you after the test. How do I prepare for a VQ scan? What happens during a VQ scan? What happens after a VQ scan? A VQ scan, also called a Ventilation V Perfusion Q scan, is made up of two scans that examine air flow and blood flow in your lungs. The first scan measures how well air flows through your lungs. The second scan looks at where the blood flows in your lungs.
If the lungs are working properly, the air flow seen on the ventilation scan will match the blood flow seen on the perfusion scan. A mismatch between the ventilation and perfusion scans V better than Q could indicate a blockage or PE. This substance sends out rays which show up any areas where there is abnormal blood flow or air flow. A VQ scan can help to diagnose a blood clot in the lungs. If left untreated, blood clots can be fatal.
If you have symptoms of a blood clot, such as shortness of breath and a sharp pain when you breathe in, your doctor might recommend a VQ scan. The gamma camera is to be placed close to you to acquire the images. Women who are breast-feeding need to make special preparations for after the scan. This will involve stopping breast-feeding for approximately 24 hours. This is due to the radioactivity in your breast milk after the scan injection. You should discuss this with your referring doctor or with the nuclear medicine practice where you will be having the test.
You might need to have bottles of formula or previously expressed breast milk available. VQ scans can be carried out if you are pregnant. Usually only the injected radiopharmaceutical is used and the dose of radioactivity is reduced to minimise the radiation to the developing foetus unborn baby. Part 1 You will be given a small dose of radioactive material radiopharmaceutical to breathe in through a nebuliser for a few minutes, with guidance from the nuclear medicine technologist who is carrying out the scan.
A nebuliser is a small machine that changes liquid into an aerosol or mist , which is breathed in, usually through a tube-like mouthpiece or a special mask that fits over your nose and mouth. You will then lie down on a table and images of your lungs will be taken at several different angles by a gamma camera. This is a special nuclear medicine camera that identifies where the radioactive material has gone to in the lungs.
Part 2 The nuclear medicine technologist will then inject a different radiopharmaceutical into a vein in your arm. A second set of images of your lungs will be taken. The entire imaging process will take 30—60 minutes.
While the images are taken, you will be asked to breathe gently and to keep still, otherwise the images will be blurry and might need to be repeated.
The medical radiation technologist will ensure that you are comfortable throughout the whole process. The radiopharmaceuticals you received will be eliminated from your body within 24 hours of the scan. Part of the radioactive material will pass out of your body through your urine and the rest of the radioactive material will completely decay away or disappear. There are no after effects from a VQ scan. The radioactive material used in a VQ scan is not known to interfere with any food or medications you might be taking.
There are minimal risks involved in the VQ scan. Allergic reactions to the radiopharmaceuticals are rare and will be treated as needed.
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