SPECT Scan

A SPECT scan is a type of imaging test. It uses radiotracers and a special camera to take detailed, 3D pictures of the organs, tissues and bones inside your body. A SPECT scan tells your healthcare provider how well your organs function, like which areas of your brain are most active or how well blood flows through your arteries to your heart.

Overview

What is a SPECT scan?

A single-photon emission computerized tomography (SPECT) scan is a type of nuclear medicine imaging test. Nuclear imaging uses radiotracers (radioactive substances) that help healthcare providers get detailed pictures of specific areas in your body.

What does a SPECT scan show?

In addition to showing what the structures inside your body look like, a SPECT scan shows how blood flows through your arteries and veins to your organs and tissues.

The most common types of SPECT scans include:

  • SPECT brain scan.
  • SPECT heart scan.
  • SPECT bone scan.

Depending on your situation, your provider may do a regular SPECT scan or a SPECT/CT scan. A SPECT/CT scan combines two types of scans (single photon emission computed tomography and computed tomography).

SPECT brain scan

A SPECT brain scan detects altered blood flow in your brain. It can tell your provider which areas of your brain are most active and least active.

SPECT brain scans help diagnose neurological conditions like:

SPECT heart scan

This type of SPECT scan can show your provider how well your heart works. It can help diagnose a wide range of conditions, including:

A SPECT heart scan can also tell your provider how well you recover after triple bypass surgery or other heart procedures.

SPECT bone scan

A SPECT bone scan can find issues that other imaging tests can’t detect, like:

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Test Details

How does a SPECT scan work?

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

  1. 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.
  2. 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.

Preparation time depends on which radiotracer substance your provider uses. Each type absorbs into your system at a different rate. When you arrive for your appointment, your provider will inject the radiotracer. Less commonly, your provider may need to inject the radiotracer several hours or days before your SPECT scan. They’ll let you know if this applies to your situation.

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 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.
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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?

Most people do well with SPECT scans, but you shouldn’t have one if you’re:

  • Pregnant or nursing.
  • Allergic to radiotracers (this is rare, but possible).

Results and Follow-Up

When should I know the results of my SPECT scan?

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.

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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.

A note from Cleveland Clinic

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.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 09/21/2023.

Learn more about our editorial process.

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