SPECT Scan
 

Test Details

How does a SPECT scan work?

A SPECT scan involves two main steps. Your provider will:

• Give you a radiotracer. A radiotracer is a radioactive substance that helps highlight certain areas in your body on an imaging test. Providers usually inject radiotracers into a vein. But in some cases, you may need to swallow or inhale the substance. As the radiotracer moves through your body, it accumulates in certain areas. This gives your provider information about how your organs and tissues function. Radiotracers are safe. They contain very minimal amounts of radiation — about the same amount you get from a regular X-ray. They don’t contain dyes or cause side effects and they leave your body within 24 hours.
• Take pictures with a gamma camera. A gamma camera (nuclear camera) uses specialized imaging techniques to look for the radiotracers in your body. You can think of a gamma camera as a radiation detector. It doesn’t emit radiation, but it finds radioactive energy (in this case, the radiotracer) inside your body. The gamma camera takes pictures of your organs, bones and tissues, and tells your provider how well they’re working.

 

How do I prepare for a SPECT scan?

Your provider will give you specific instructions for your situation. In general, you should wear comfortable clothing and leave jewelry, watches and other metal items at home.

You'll receive a radioactive substance through an intravenous (IV) infusion into a vein in your arm. The tracer dose is very small, and you may feel a cold sensation as it enters your body. You may be asked to lie quietly in a room for 20 minutes or more before your scan while your body absorbs the radioactive tracer. In some cases, you may need to wait several hours or, rarely, several days between the injection and your SPECT scan.

Your body's more active tissues will absorb more of the radioactive substance. For instance, during a seizure, the area of your brain causing the seizure may hold on to more of the radioactive tracer. This can pinpoint the area of the brain causing your seizures.

 

What to expect during a SPECT scan

Once your body absorbs the radiotracer, your provider will walk you to a room with a SPECT machine. You’ll lie down on a table (usually on your back) while the scanner rotates around you. The SPECT machine will take pictures of the structures inside your body. Then, it’ll send the information to a computer, which will create detailed 3D images.

A SPECT scan usually takes about 30 minutes to complete. It may take longer if your provider needs to take pictures of other areas. Once you leave your appointment, you can resume normal activities immediately.

 

What to expect after the test

Most of the radioactive tracer leaves your body through your urine within a few hours after your SPECT scan. You may be told to drink more fluids, such as juice or water, after your SPECT scan. This helps flush the tracer from your body. Your body breaks down the remaining tracer over the next few days.

 

What are the advantages of a SPECT scan?

 

SPECT scans:

• Are safe for people with pacemakers and other cardiovascular implantable electronic devices (CIEDs).
• Can find issues that other imaging methods can’t detect.
• Can tell your provider how well your organs function.

 

Are there any risks or possible complications?

Your healthcare provider will use a small amount of radiation during a SPECT scan. The exact dosage depends on factors like your size and what type of radiotracer your provider uses.

Risks from radiation during a SPECT scan are minimal. Talk to your healthcare provider if you have questions or concerns about your radiation exposure.

 

Who shouldn’t undergo a SPECT scan?

For most people, SPECT scans are safe. If you have an injection or infusion of radioactive tracer, you may experience:

• Bleeding, pain or swelling where the needle was inserted in your arm.
• Very rarely, an allergic reaction to the radioactive tracer.

Be sure to tell your healthcare team or radiation technologist if there's a possibility you're pregnant or if you're breastfeeding.

 

Risks of radiation

Your healthcare team uses a small amount of radiation to perform a SPECT scan, and the test is not associated with any long-term health risks. Talk to someone on your team if you're concerned about your exposure to radiation during a SPECT scan.

When should I know the results of my SPECT scan?

A radiologist or healthcare specialist with advanced training in nuclear medicine will study the results of your SPECT scan and send them to your healthcare team. Pictures from your scan may show colors that tell your team what areas of your body absorbed more of the radioactive tracer and which areas absorbed less. For instance, a brain SPECT image might show a lighter color where brain cells are less active and darker colors where brains cells are more active. Some SPECT images show shades of gray, rather than colors. Ask your healthcare team how long to expect to wait for your results.

You should get the results of your SPECT scan back in about one week. After your appointment, a radiologist will interpret the images captured during your scan. Then they’ll create a report of their findings to share with the provider who ordered the test. Your provider will talk with you about your results and determine any appropriate next steps.

Additional Details

What is the difference between a SPECT and CT scan?

A CT (computed tomography) scan uses radiation to take detailed pictures of the structures inside your body. The main goal of a CT scan is to look at your anatomy. It shows the size and location of organs, bones and tissues.

A SPECT scan involves injecting, ingesting or inhaling a radiotracer before taking images. The main goal of a SPECT scan is to look at your physiology — how the radiotracer behaves once it’s inside your body. This is helpful for determining how your organs and tissues function.

In some cases, a healthcare provider may combine CT and SPECT technology to get even more detailed information. Some scanners can take both types of images at the same time.

 

What is the difference between a SPECT scan and an MRI?

Magnetic resonance imaging (MRI) uses a large magnet and radio waves to take pictures of the structures inside your body. Like a CT scan, MRI can tell you a lot about your physical anatomy — but it can’t tell you how your anatomy functions.

A SPECT scan, on the other hand, shows how your organs and tissues work. After your provider injects the radiotracer, the substance moves through your body and accumulates in certain areas. How the radiotracer behaves can tell your provider whether your organs, bones and tissues function as they should.

 

One Final Note..

Providers can use SPECT scans to evaluate any area of your body. But this type of imaging is most common for detecting heart, brain and bone conditions. Talk to your healthcare provider to learn more about SPECT scans and whether you need one.