Parathyroid scans are performed in patients with biochemical evidence of hyperparathyroidism, and are being considered for surgery for a suspected parathyroid adenoma. Parathyroid adenomas are localised using a radiopharmaceutical called sestamibi. This is injected into the vein, and localises in parathyroid and thyroid glands. However, it is absorbed faster and ‘washes out’ later in a hyperfunctioning parathyroid gland compared to a normal parathyroid gland. At Trinity Medical Imaging we combine several imaging modalities to give much greater accuracy than a single scan alone. We can combine the sestamibi scan with a multiphase contrast enhanced CT, and an ultrasound scan of the neck. Often these three scans can be performed in one attendance at your convenience. By using this technique, we can accurately localise the majority of parathyroid adenomas. Not only is the parathyroid adenoma accurately localised, the anatomical information provided by the SPECT-CT study allows a definitive surgical approach to be planned. This enables the surgeon to use a minimally invasive technique to excise the adenoma.
At Trinity Medical Imaging the combined use of SPECT-CT, contrast enhanced CT and ultrasound provides unrivalled accuracy in detecting parathyroid adenomas.
Parathyroid scan preparation
What is a nuclear medicine parathyroid scan?
A parathyroid scan is used in nuclear medicine to look at possible problems involving the parathyroid gland(s). The parathyroids are four small glands lying close to or embedded in the back surface of the thyroid gland, which is situated in the front of your neck.
The parathyroid scan uses sestamibi (or MIBI for short), which is a very safe liquid radioactive compound that is injected into the body and absorbed by the overactive parathyroid but not by the healthy ones. A hyperactive gland is picked up by the scan on the images taken by the gamma camera.
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 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.
Is there any special preparation for the scan?
There is no special preparation necessary prior to the scan. You may eat and drink as normal. You should take any medicines you need as usual. 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. You do not need to undress but you should remove any jewellery and metallic objects such as keys, coins or buckles.
What happens during the scan?
You will be taken to the examination room and made comfortable either sitting down. The technologist will inject the MIBI solution into a vein in your arm and then position the gamma camera over your neck and chest. During the scan the gamma camera will rotate around you, taking images of your parathyroid glands.
Once the pictures are completed you will be asked to return in 2-3 hours for further pictures of your neck and chest. No further injections are given for the second session. The second scan will be identical to the first, but we will also perform a CT (or CAT scan) of your neck and chest. When this happens, the table will move in and out, but otherwise you won’t feel anything. Your technologist will explain when this is happening.
Will it be uncomfortable?
No. Apart from the injection, you will not feel anything.
How long will it take?
The scanning process usually takes about 30 minutes, and your total time in the department should be about one hour.
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.
Are there any after-effects?
The radiopharmaceutical 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, mothers with young children should notify the radiographer, 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 them 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.