There are lots of different types of nuclear medicine scans (sometimes called radioisotope scans). They all involve taking pictures which show the function of different parts of the body. They are different to X-ray pictures which show any anatomical abnormalities.
The information in this section only gives some general information about nuclear medicine scans. More specific information about some common tests can be found by following this link NMTEST. If your doctor thinks that you need a nuclear medicine scan you should receive information about the particular test that you are to have from the department that will be carrying out your scan. This may be an X-ray department or a specialist nuclear medicine department. Please read any information that you receive from the department very carefully, as the details for your test may differ from the general information given here.
Is it safe for me to have the scan?
For any nuclear medicine scan it is necessary to give you a small amount of radioactive tracer, called a radiopharmaceutical, in order to take the pictures. The small risk (similar to or less than a CT scan) from this 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 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 contact the department where you will be having your scan. Do this as soon as possible as the scan may be postponed if it is not urgent.
Also contact the department if you are breast-feeding, as they may give you special instructions.
Preparation for your scan
Some nuclear medicine scans may require you to stop taking certain medicines, or to avoid caffeine, or not to eat anything for a while before the scan. Therefore it is very important that you follow any instructions that you are given by the department that will be doing your scan. If you don’t receive any specific instructions about preparation then you can eat and drink normally before your appointment.
For all nuclear medicine scans you will need to receive a small amount of radioactive tracer. This will usually 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. For some types of scan you may be asked to drink or breathe the radioactive tracer instead.
For some scans the pictures will be taken immediately after your injection. However for other scans you may be asked to wait before the pictures can be taken. The length of waiting time is different for each type of scan and it can be up to 3 hours, so read the information given for your particular test. If the waiting time is long you may be allowed to leave the department during this time if you wish.
Before the scan you may be asked to go to the toilet to empty your bladder.
For most scans you will not have to get undressed, but you will be asked to remove any metal objects like braces, jewellery and belts that are within the area where the pictures are to be taken.
The scan pictures are taken by a special machine. For most nuclear medicine scans the machine used is called a gamma camera, but for PET scans a PET scanner is used.
One of the clinical staff will be watching you all the time to make sure that you are OK.
The gamma camera
The gamma camera may have one or two large detectors. It 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.
For some scans you will be asked to lie flat on your back on a special couch. For other scans you may be asked to sit in front of the camera. The scans usually take between 10 and 30 minutes and it is very important that you keep still during this time. If you think that you will find this difficult please speak to the nuclear medicine department before your appointment.
For some types of scan some additional pictures may also be taken with an X-ray CT scanner in order to localise any abnormality better. These extra pictures only take a few minutes.
The PET scanner
PET is short for Positron Emission Tomography. The PET scanner has a short tunnel that you will have to go into (like a CT scanner) but it does not make any loud noises (unlike an MR scanner). All that you will have to do is to lie as still as you can on the scanner couch for about 30 minutes.
The scanner will also take some additional images using an X-ray CT scanner, but these only take a few seconds. The CT images are used to help identify the exact location of any uptake seen on the PET scan.
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 some tests, 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, but for some tests you may be advised to drink plenty of liquids as this will help clear the radioactivity more quickly.
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 scan pictures 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 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.