SPECT/CT Scan (Nuclear Medicine)

Many people have an MRI that shows wear and tear at several levels of the spine, and the question becomes: which one is actually causing my pain? A SPECT/CT scan is one test that can help answer that. It shows not only what the spine looks like, but which areas are most active right now.

SPECT stands for single-photon emission computed tomography. It is a nuclear medicine test that makes 3D pictures of where a small amount of radioactive tracer has collected in your body. The tracer is the same kind used in a bone scan. It gathers in bone that is actively remodeling, such as bone that is inflamed, stressed, healing or under extra strain.

In a SPECT/CT scan, those glowing areas are combined with a low-dose CT scan taken at the same visit. The CT shows the exact bone, joint or disc level, so the active spot can be matched to the precise part of your spine.

Areas with more tracer show up as “hot spots.” Dr. Grunch may order a SPECT/CT scan when she needs to find out which structure is most likely generating your pain, for example:

• When an MRI or CT shows changes at several levels, such as disc degeneration, and it is not clear which level is the painful one
• When facet joint or sacroiliac (SI) joint pain is suspected
• To look for small stress fractures in the spine, including in the back of a vertebra, that may not show up on X-ray
• To check whether a fusion has healed or whether there is loosening around hardware, which is helpful in people who have had spine surgery before
• When an MRI is not possible, or when metal hardware makes MRI pictures harder to read

A hot spot shows where activity is. It does not prove by itself that the spot is the cause of your pain, so Dr. Grunch always compares it with your symptoms, your exam and your other imaging. Research on SPECT/CT for spine pain is still growing, and it works best as one piece of the full picture rather than a stand-alone answer.

• Follow the instructions from your imaging center. They may differ slightly from place to place.
• Drink plenty of fluids. Most centers let you eat and take your medicines as usual.
• Tell the center if you are pregnant or breastfeeding.
• Tell them if you recently had a test with barium or another nuclear medicine scan.
• Tell them about any implant, such as a spinal cord stimulator, pain pump or pacemaker.
• Never stop a blood thinner on your own. Ask the doctor who prescribes it.
• Wear comfortable clothes without metal.
• Plan for several hours, including a waiting period. Bring something to read.
• If you are anxious or claustrophobic, let us and the center know before the test.

A technologist injects the tracer into a vein in your arm. You then wait about two to four hours while it settles into your bones, and you can usually leave and come back during this time. You will be asked to drink extra water and to empty your bladder right before the pictures.

For the scan, you lie still on a table while a camera moves slowly around the area being studied. The low-dose CT is done during the same visit. Neither part is painful or noisy, and you can usually talk with the technologist throughout. SPECT/CT takes longer than a standard bone scan, and your imaging center can tell you how much time to plan for.

You can return to your normal activities right away. Drink plenty of fluids and empty your bladder often for the rest of the day to help the tracer leave your body. A radiologist reads the scan, and Dr. Grunch or one of her physician assistants will go over the results with you and explain what they mean for your treatment plan. That plan may include diagnostic injections, other non-surgical treatment or, when it fits, a procedure that can often correct the problem.

SPECT/CT uses a small amount of radiation, from the tracer and from the low-dose CT. The tracer leaves your body within a day or two. Allergic reactions to the tracer are very rare. The test is generally avoided during pregnancy, and breastfeeding mothers may be asked to pause for a short time. Dr. Grunch orders it only when the information is likely to help guide your care.

What is the difference between a bone scan and a SPECT/CT scan?

A standard bone scan gives a flat picture of tracer activity, often of the whole body. SPECT/CT makes 3D pictures of one area and lines them up with a CT, so the active spot can be tied to the exact bone or joint.

Can a SPECT/CT scan show exactly what is causing my pain?

It can point to the area that is most active, which often narrows down the possibilities. But a hot spot is a clue, not a final answer. Dr. Grunch compares it with your symptoms, exam and other tests, and sometimes a diagnostic injection, to decide what is most likely causing your pain.

If I already had an MRI, why do I need a SPECT/CT?

An MRI shows structure. SPECT/CT shows activity. Many people have wear and tear on MRI at several levels, and SPECT/CT can help show which level is most active. It may also be used when MRI is not possible or when hardware makes MRI hard to read.

Am I radioactive after a SPECT/CT scan?

You give off a very small amount of radiation for a day or so. Drinking fluids and emptying your bladder often helps it leave your body faster.

Will insurance cover a SPECT/CT scan?

Coverage differs from plan to plan. Call the imaging center and your insurance company about scheduling, cost and any approval needed before the test.

If Dr. Grunch has ordered a SPECT/CT scan for you and you have questions, call 470-293-9800 or contact us. You can also ask general questions any time through our “Ask Us Anything” chat. For questions about scheduling, cost or arrival time for the test itself, call the imaging center where it is booked.

Related: All imaging and diagnostic tests · Bone scan · Facet joint disease · Sacroiliac dysfunction

This information is for educational purposes only and is not medical advice. It does not replace individualized care from a licensed physician. Please talk to your provider about your symptoms and follow the instructions from your imaging center.