white cell scan
Sometimes a joint replacement can become infected and making the diagnosis can be difficult. Removing an infected prosthesis is a large undertaking and not without risk. At Trinity Medical Imaging we can provide anti-granulocyte antibody imaging with SPECT-CT. This technique involves injecting radiolabelled antibodies which bind to the body’s white blood cells, which will migrate to the site of infection. The hybrid SPECT-CT scanner is able to localise the site of infection accurately and provide detailed anatomical information about the extent of infection. This technique is effective for both osteomyelitis (bone infection) and soft tissue infection.
Often a combination of a bone SPECT-CT with anti-granulocyte antibody imaging is needed in diagnosing complex problems such as diabetic arthropathy.
Infection imaging preparation
In the case of a white-cell scan or antigranulocyte antibody imaging scan with SPECT-CT, you will receive an injection in your arm of a radiopharmaceutical. Usually we will perform a scan at about 3–4 hours after the radiopharmaceutical has been absorbed by the tissues.
When the pictures are being taken, the gamma camera moves over the body to detect the gamma rays coming from the radiopharmaceutical in the tissues. This creates an images of the sites of infection in the body. This can highlight information which helps the doctor to diagnose your condition.
Are there are any risks?
As the gamma rays are similar to X-rays, there are small risks associated with being exposed to radiation. However, the radiation decays away over a few hours and the amount of radiation used in medical imaging is very low. This is comparable to the natural radiation we all receive from the environment over about two years. In fact, the risks from missing a disorder by not having a bone scan may be considerably greater than the risks of the radiation. If you are concerned about the risks of the radiation, please speak to a member of our team.
Are you required to make any special preparations?
No specific preparations are required. You may eat and drink normally and you should take any medicines you need as usual. After the injection you should drink plenty of fluids – unless you normally have to restrict your fluid intake. If you leave the department, you do not need to take any special precautions, but if you stay then you should use the special toilet for nuclear medicine patients. Your technologist will show you where the toilet in the department is.
If you are pregnant or breastfeeding
If you are pregnant, or think you may be pregnant, you mustinform the department before attending, and certainly before the radiopharmaceutical is administered.
If you are breastfeeding, please inform the department before attending and you will be advised as to whether you will need to take any precautions. You may be advised to avoid breastfeeding for a few hours afterwards and you may need to express milk before your scan.
Can you bring a relative/friend?
Yes you can, but for reasons of safety, they may not be able to accompany you into the examination room, except in very special circumstances. Please do not bring children with you as they will potentially be exposed to radiation from other patients.
Arriving for your appointment
When you arrive for your appointment, please go to the reception desk, after which you will be shown where to wait until collected by a technologist.
The technologist will explain the procedure, and you can ask any questions. You may be asked some questions about your health, or whether you have had this examination before.
The technologist will then give you the injection of radiopharmaceuitcal preparation into a vein in the arm. This is just like having blood taken.
What happens during the scan?
You do not need to undress but please remove any jewellery or metallic objects such as keys, coins or buckles. You will be taken to the scanner room and made comfortable lying on the couch. The technologist will position the gamma camera over the main joint being examined and this early phase of the study will last up to 15 minutes.
You will then be free to leave the department and asked to return in approximately three hours, during which time you can eat and drink as normal. On your return, you will be asked to visit the special toilet to empty your bladder. The technologist will position the gamma camera over one end of your body and ask you to lie still. You can breathe normally throughout. Usually, the camera will slowly scan the whole length of your body. Sometimes the camera takes pictures in segments.
The technologist will remain in the control room and watch you through the glass screen in the examination room. It may be necessary to take one or two more localised views, if more detail is required. Afterwards, it will usually be necessary to perform a special scan called a CT (or CAT) scan. Your technologist will tell you if this is going to happen. During this scan, the table will move forwards and backwards through the ‘doughnut’ shaped scanner.
Will it be uncomfortable?
No. Apart from the injection, you will not feel anything.
Can I listen to music while I have my scan?
Your technologist will ask you whether you would like to listen to music during your scan. You may bring in a CD or select music from our selection.
How long will it take?
Apart from the 3 hours while the isotope is absorbed into the bones, the scanning process usually takes about 30 minutes, and your total time in the department will usually be less than one hour.
Are there any side-effects?
No, the injection causes no side-effects, nor will you feel drowsy. You can drive home afterwards and go about your normal activities.
In addition to mothers who are breastfeeding, parents with young children should notify the technologist, who will explain that it is advisable not to have prolonged close contact with them for the rest of the day. This is to avoid their being exposed to unnecessary radiation.
When will you get the results?
The scan will be examined after your visit and a written report on the findings will be sent to your referring doctor within 7 days.
The radiopharmaceutical required for this examination is ordered especially for you. If you cannot attend your appointment, please let the department know as soon as possible, so that we can use it for someone else.
We hope that this leaflet has answered your questions, but remember that this is only a starting point for discussion about your treatment with the doctors looking after you. Make sure you are satisfied that you have received enough information about the procedure.