What Is a SPECT Scan?

What to expect when undergoing this test

Single-photon emission computerized tomography (SPECT) scans use radioactive materials and a specially designed gamma camera to produces three-dimensional images of the inside of your organs. This type of imaging provides a non-invasive way for doctors to evaluate the health of certain parts of your body, most commonly the heart, brain, and bones.

What makes SPECT scans different from other methods of imaging is that the scan can show how well certain organs are functioning. For example, the images made by the SPECT scan can help pinpoint the location of seizures in people with epilepsy and assess whether there's sufficient blood flow to different areas of the brain.

what to expect during a SPECT scan
Illustration by Emily Roberts, Verywell

Purpose of Test

SPECT scans can be used for a variety of purposes, which is why they're readily available at most hospitals, clinics, and imaging centers. Some of the reasons your doctor may choose to order this test include the suspicion or need for monitoring of:

  • Brain and neurological conditions
  • Cardiac conditions
  • Bone disorders

SPECT, like other nuclear scans, uses radioactive tracers—carrier molecules that are bonded with radioactive atoms, to evaluate, diagnose, and treat a range of illnesses. Different tracers perform different functions, and the doctor chooses the tracer that’s appropriate for you depending on your symptoms or disease that’s being be evaluated.

Brain and Neurological Conditions

SPECT scans can be used to gather information about changes in brain function due to disease processes, including:

Cardiac Conditions

Radioactive tracers used during a SPECT scan can capture how well your heart is working, and, ultimately, disease processes that may be going on in the heart. Some of the issues it can detect include:

  • Narrowing of the arteries
  • Clogged arteries
  • Scar tissue due to heart attacks
  • Inefficient pumping of blood
  • Whether surgical procedures, such as bypass surgeries or other surgeries, were successful

Bone Disorders

SPECT scans can be useful in bone disorders because areas of concern will often "light up" on the images. The conditions that can be explored using this technology include:

  • Less visible bone fractures, such as stress fractures
  • Bone cancer or cancer that has metastasized to areas of bone
  • Bone infections

Risk and Contraindications

Most people tolerate SPECT scans well, but there may be some instances when the test would be ill-advised. Your doctor may opt not to perform this test for the following reasons:

  • You’re pregnant or nursing: The tests use a low dose of radiation, which is not recommended for pregnant women. If you’re breastfeeding, you may be required to wait a certain amount of time before nursing to allow your body time to excrete the radioactive tracer.
  • You're allergic to the tracer: Though unusual, this kind of allergy is possible, and you shouldn't have the scan if you have a known allergy to the tracer. If you have an allergic reaction while undergoing the scan, know that the healthcare professionals around you are equipped to handle the situation.

Radiation Risk

Since the SPECT scan does use a low dose of radiation, talk with your doctor if you have any concerns about your risk of exposure. No long-term health risks have been associated with using this method of imaging. 

Before the Test

The things you may need to do to prepare for the scan can differ depending on the reason you're having it done. Your healthcare team should give you specific guidelines for preparation.

Timing

Ask your medical team about the amount of time you should set aside for the scan. Some take about 30 minutes, with others may require more or less time depending on the reason for the SPECT scan.

Location

Testing may be done in a hospital, clinic, or imaging center. Typically, the scan will be done by a medical team that specializes in nuclear medicine.

What to Wear

You can wear what you want for the procedure, but you’ll likely be asked to change into a gown before the scan. You may find that casual, loose-fitting clothing is a comfortable choice for the test. Leave metal items, like watches, jewelry, and earrings, at home.

Food and Drink

Your healthcare team will let you know if the scan requires you to avoid certain foods or drinks. For example, if you have a SPECT scan for cardiac reasons, you may need to avoid caffeine for several hours before the test.

Cost and Health Insurance

Your insurance may require prior authorization in order to cover your SPECT scan. Be sure to check with the company on whether and to what extent the scan is covered so you'll know what, if any, costs you'll need to cover.

SPECT scans, without insurance coverage, can cost over $1,000.

What to Bring

Bring your insurance card, a form of identification, and any paperwork you’ve been asked to fill out before the scan.

Other Considerations

Make sure your doctor has a current list of all the medications, including over-the-counter products and supplements, that you’re taking. He or she may want you to stop taking certain ones before the procedure. Also, let your doctor know if you’re pregnant or nursing.​

During the Test

The test consists of two parts: injecting the radioactive tracer and the SPECT scan itself.

Pre-Test

An intravenous (IV) line will be inserted into your arm. The radioactive tracer will then be injected via the IV. You may feel a cold sensation as the tracer flows into your bloodstream. Once the tracer has been injected, your technician or doctor will instruct you as to how long you need to wait before beginning the scan so that the tracer can be fully absorbed by your body.

The wait could be as short as 20 minutes. In some cases, though, it could take hours or days for the absorption to happen. Your medical team will provide you with information on this process.

Throughout the Test

During the scan, you’ll be asked to lie on a table. The gamma camera will rotate around your body, creating three-dimensional images of your internal organs and tissues.

The scan doesn’t cause pain, so if you experience pain or discomfort, be sure to let your doctor or technician know so that they can help you get more comfortable.

Post-Test

Once the scan is completed, you can usually leave and resume your daily activities right away.

After the Test

Staying hydrated will help your body flush out the remaining portion of the radioactive tracer over the next couple of days.

Again, if you are breastfeeding, you may be required to hold off nursing for a period of time while the tracer exits your system. Follow any special instructions given to you by your healthcare provider.

Interpreting Results

Your SPECT scan images will show bright or dark areas, either in color in grayscale, where the radioactive tracer has been absorbed by your organs and tissues.

Your results aren’t likely to be ready immediately. A radiologist or nuclear medicine physician needs to evaluate the results and report the findings to your doctor.

Your doctor or a member of their staff will contact you to talk about the results and whether additional testing is needed. One thing to keep in mind is that you can request copies of your SPECT scan images and the report for your personal records, or if you’d like to get a second opinion.

Follow-Up

The nature of any follow-up you may need after your SPECT scan depends on what, if anything, the test discovered. Be sure to ask your doctor whether you'll need any further diagnostic testing, monitoring, or appointments based on the findings.

A Word From Verywell

Going through the testing process can be a bit nerve-wracking. To help you feel more at ease, make sure your doctor takes the time to address your fears or concerns. This will go a long way toward helping you feel more comfortable.

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