Parathyroid Scan

What is a parathyroid scan?

A parathyroid scan is a safe and painless imaging procedure healthcare providers use to locate one or more overactive parathyroid glands. The imaging test is usually an ultrasound or a nuclear scan.

Why would I need a parathyroid scan?

Your healthcare provider might order a parathyroid scan when blood tests show you have hyperparathyroidism (too much calcium in your blood), and they believe surgery is the best treatment for it. This scan helps pinpoint the overactive gland or glands so surgeons can remove them. The images from the scan help to make the surgery minimally invasive. It’s not always necessary for a diagnosis or surgical planning.

Your provider may also recommend a parathyroid scan if you have ectopic glands (glands in an abnormal position) to find their location.

What are the types of parathyroid scans?

There are a few different kinds of parathyroid scans. Together, you and your healthcare provider will determine the best option for you.

The two most common types of parathyroid scans are an ultrasound and a nuclear scan (also known as a sestamibi scan or MIBI). Sometimes, providers use both imaging tests to get an accurate image of the overactive gland(s).

Ultrasound parathyroid scan

An ultrasound is a safe, medical imaging test that uses sound waves to create real-time pictures or video of internal organs or other tissues, such as blood vessels and glands. Ultrasound enables healthcare providers to “see” details of soft tissues inside your body without making any incisions.

Nuclear parathyroid scan

There are a few different kinds of parathyroid nuclear scans and the processes are a little bit different for each kind. In general, a nuclear scan involves your provider injecting a safe, radioactive liquid (radiotracer) into a vein. The radioactive liquid flows through your bloodstream, and your parathyroid glands absorb the liquid.

A special camera then takes images of your parathyroid glands. The overactive parathyroid gland(s) will appear enlarged and “bright” in the image. Most nuclear parathyroid scans involve more than one session of imaging so your provider can compare the pictures with each other.

Types of parathyroid nuclear scans include:

• Single-phase dual-isotope subtraction imaging. This nuclear parathyroid scan requires two different injections of two radiotracers (sestamibi and pertechnetate) into your vein at different times. A special camera takes pictures of your parathyroid glands after each injection.
• Single-isotope dual-phase imaging. For this nuclear parathyroid scan, a provider injects a single radioactive liquid into your vein (sestamibi). A special camera then takes pictures of your parathyroid glands 10 to 15 minutes after the injection and again 90 minutes to three hours later.

There are also different types of imaging machines that your provider could use during a parathyroid scan (MRI, PET scan, etc.). Your healthcare team will decide the best option for you.

How do I prepare for a parathyroid scan?

Your healthcare provider will let you know if you need to follow specific instructions before your parathyroid scan, like whether you’re able to eat or drink before the scan.

You’ll likely have to remove jewelry and accessories before the scan because they might interfere with the imaging process.

If you’re undergoing a nuclear scan, it’s essential to tell your healthcare provider if you’re pregnant — or if you think you might be — or if you’re breastfeeding.

What should I expect during a parathyroid scan?

The process for your parathyroid scan depends on what type of scan you’re getting.

Ultrasound parathyroid scan process

If you’re having an ultrasound as your parathyroid scan, you’ll typically lie on your back on an exam table with a shoulder roll or pillow under your neck.

The ultrasound technician will:

1. Apply gel. You’ll have a small amount of gel on the skin of your neck. This gel doesn’t harm your skin or stain your clothes, and rinses off with water.
2. Use the ultrasound probe (transducer). The technician will move a handheld instrument that looks like a microphone over the gel. The technician will move the probe around on your skin. This is how the technician takes “pictures” of your parathyroid glands.
3. Ask you to hold still. Being very still can help create clearer pictures.
4. Clean your skin. The technician will wipe off any remaining gel on your skin.

Nuclear parathyroid scan process

There are a few different kinds of parathyroid nuclear scans. Your healthcare provider will give you specific details of what to expect. Don’t be afraid to ask them questions.

In general, a nuclear scan involves a safe, radioactive liquid (radiotracer) that a provider injects into one of your veins. This liquid is safe, but you may feel a slight pinch when your provider injects it with a needle.

You’ll then lie on your back on an exam table while your provider uses an imaging machine to take images of your parathyroid glands.

You shouldn’t have any side effects after your nuclear parathyroid scan, and you’ll be able to drive home after the test.

How long does a parathyroid scan take?

An ultrasound usually takes 30 minutes to an hour.

The entire nuclear parathyroid scan procedure generally takes two to five hours, depending on the specific type of scan.

When can I expect the results from my parathyroid scan?

Depending on the type of parathyroid scan you have, a radiologist or another specialist will interpret the images and send a report to your healthcare provider and surgeon. Your healthcare team will then schedule an appointment with you to go over the results. This can take several days to a week.

What does an abnormal test result mean?

A parathyroid scan shows which glands your surgeon needs to remove.

Abnormal results of a parathyroid nuclear scan show “hot spots” or areas that quickly absorb the radioactive tracer. This tells your surgeon that the gland will need removal.

The results from a parathyroid ultrasound are abnormal when your parathyroid gland is enlarged.