A lung scan is a nuclear medicine test that looks at your lungs. There can be two parts to a lung scan. One part looks at the blood flow to your lungs (this is called the perfusion) and the other part looks at the airflow to your lungs (called the ventilation). By comparing the two sets of pictures it is possible to investigate various lung conditions, but it is most commonly used to detect a pulmonary embolism (PE). This is a blockage of one of the arteries in the lung caused by a blood clot. You may need to have both parts of the test or just one.
Is it safe for me to have the scan?
For this scan it is necessary to inject a small amount of radioactive tracer, called a radiopharmaceutical, and to breathe in a radioactive gas. The small risk from this (less than a CT scan) is outweighed by the information that will be gained by taking the scan. A doctor will have checked the request to make sure this is the appropriate test for you.
If you have any concerns or would like further information, please contact the department where you are having your lung scan. If you don’t understand why you need to have this scan please speak to the doctor who referred you.
For female patients
If you know that you are pregnant, or there is any chance that you may be pregnant, then please tell staff in the department where you will be having your lung scan so that they can discuss this with you. In urgent cases it is still safe for you to have a lung scan even if you are pregnant because the risk to your unborn child is very low.
If you are breast-feeding you should also contact the department before your appointment as they may give you special instructions.
Preparation for your scan
There are no special preparations for a lung scan. You can eat, drink and take any medicines as normal.
For the perfusion part of the scan a small amount of radioactive tracer will be injected into a vein in your arm or hand. You may have had a blood test in the past; this is much the same. The ‘pinprick’ of the needle may hurt a bit, but that is all.
The tracer for the perfusion part of the scan is made from specially treated human albumin. This is a protein that is obtained from screened blood donations.
If you need to have the ventilation part of the scan you will also be asked to breathe in air mixed with a small amount of radioactivity. Depending on the equipment used in the department that you attend, this will be given to you either through a face mask that goes over your mouth and nose, or a mouthpiece that you hold in your mouth. You will not have to hold your breath.
You will not have to get undressed, but you will be asked to remove any metal objects like braces, jewellery and belts before you lie on the bed of the scanner.
The scans are taken by a special machine called a gamma camera. This is not a tunnel, but the camera detector will come close to you. There are sensors in the camera which stop it moving if it touches anything, so it cannot hurt you.
You will not be left on your own – there will always be someone immediately available.
Depending on the equipment used in the nuclear medicine department that you attend you may be asked to sit on a chair or to lie flat on your back on a special couch. The lying down method is most commonly used with the latest gamma cameras. In this case the scan usually takes about 30 minutes and it is very important that you keep still during this time whilst the camera rotates around you. If you think that you will find this difficult please speak to the nuclear medicine department before your appointment.
Some gamma cameras may still use the sitting up method in which case you will have to sit on a chair in front of the camera whilst several separate pictures are taken from different directions. With this method each picture takes about 5 minutes.
After your scan
It is very unlikely that you will feel any side-effects after the scan, but if you think that you have please let the nuclear medicine department know.
You may continue all your normal activities unless you have been advised otherwise.
After your scan there will be some radioactivity left in your body but this will not present a significant risk to other people around you. However, for the rest of the day, we suggest that you try to keep any time that you spend within arm’s length of pregnant women, babies and small children as short as possible; but there is no need to stop giving children essential love and care.
The radioactivity in your body will soon disappear.
It is perfectly safe for you to travel abroad after your scan, but many airports and sea ports are now equipped with very sensitive radiation detectors. So it is possible that the very small amount of radioactivity left in your body could set off a detector as you pass through security. Therefore, if you intend to travel abroad within a week following your scan, it could be helpful to take with you something to explain that you have recently had a nuclear medicine scan. This could be your appointment letter or some other official confirmation from the department where you had your scan.
Your lung scan will be looked at by a specialist doctor, who will issue a report. The report will be sent to the doctor who requested your scan rather than to your GP. This is because the doctor who requested your scan will have all the results from other tests and will be able to tell you how the result of your lung scan affects your care.
Information about you
As part of your care, information will be shared between clinical staff, some of whom you may not meet. It may also be used to help train other staff. Information collected may also be used later on to help the department improve their quality of care, plan services or to research into new developments.
The pictures from your scan may be used to teach other healthcare workers, but your name and all other identification will be removed first. It won’t be possible to identify you from the scan pictures.
All information will be treated as confidential and is not given to anyone who does not need it. If you have any concerns, please discuss these with the department.
All the staff would like to make your visit as pleasant as possible. If you have any concerns please talk to a member of the nuclear medicine staff.
This video, made in the Central Manchester Nuclear Medicine Centre, shows a patient having a Lung Scan.
A printable version of this leaflet can be found here