What is a SPECT Scan? Purpose, Procedure & Results

A SPECT scan is a special type of imaging test that shows how blood flows through your organs and tissues. Think of it as a detailed movie of your body's inner workings, rather than just a snapshot like a regular X-ray.

This gentle procedure uses a small amount of radioactive material to create 3D pictures of your brain, heart, bones, or other organs. The images help doctors see if these areas are getting enough blood and working properly.

What is a SPECT scan?

SPECT stands for Single Photon Emission Computed Tomography. It's a nuclear medicine test that tracks blood flow and activity in your organs using a tiny amount of radioactive tracer.

During the scan, you'll receive an injection of this tracer, which travels through your bloodstream. A special camera then rotates around your body, taking pictures from different angles to create detailed 3D images.

The radioactive material is completely safe and leaves your body naturally within a few days. The amount of radiation you receive is similar to what you'd get from other common medical tests.

Why is a SPECT scan done?

Doctors use SPECT scans to diagnose problems that other tests might miss. This imaging technique is especially helpful for detecting issues with blood flow and organ function.

Your doctor might recommend a SPECT scan if you're experiencing symptoms that suggest problems with your brain, heart, or bones. The test can reveal areas that aren't getting enough blood or aren't working as they should.

Here are the main reasons doctors order SPECT scans:

• Brain conditions like dementia, Alzheimer's disease, or seizure disorders
• Heart problems including coronary artery disease or heart attack damage
• Bone infections, fractures, or cancer that has spread to bones
• Lung blood clots or breathing problems
• Liver or kidney function issues
• Thyroid disorders
• Parathyroid gland problems

SPECT scans are particularly valuable because they can detect functional problems even when the organ looks normal on other imaging tests. This makes them especially useful for early detection of many conditions.

What is the procedure for a SPECT scan?

The SPECT scan procedure is straightforward and painless. Most scans take between 30 minutes to 2 hours, depending on which part of your body is being examined.

Here's what happens during your SPECT scan:

1. You'll receive a small injection of radioactive tracer into a vein in your arm
2. You'll wait 15 minutes to 4 hours for the tracer to circulate through your body
3. You'll lie still on a padded table that slides into the scanning machine
4. The camera rotates around you, taking pictures from multiple angles
5. You may need to change positions or have additional scans taken

The injection feels like any normal shot, and you won't feel the radioactive tracer moving through your body. The scanning itself is completely painless, though you'll need to stay very still to get clear images.

Some SPECT scans require special preparation or stress testing. For heart scans, you might exercise on a treadmill or receive medication to simulate exercise before the injection.

How to prepare for your SPECT scan?

Preparation for your SPECT scan depends on which part of your body is being examined. Most scans require minimal preparation, but following the instructions carefully helps ensure accurate results.

Your healthcare team will give you specific instructions based on your type of scan. Generally, you can eat normally and take your regular medications unless told otherwise.

Here's what you might need to do before your scan:

• Avoid caffeine for 12-24 hours before heart scans
• Stop certain heart medications if directed by your doctor
• Wear comfortable, loose-fitting clothes without metal zippers or buttons
• Remove jewelry, watches, and any metal objects
• Inform your doctor if you're pregnant or breastfeeding
• Tell your healthcare team about any medications or supplements you're taking

For bone scans, you'll need to drink plenty of water after the injection to help flush the tracer through your system. Brain scans might require you to avoid alcohol and certain medications for a day or two beforehand.

How to read your SPECT scan results?

Your SPECT scan results will show areas of normal and abnormal activity in colorful, detailed images. Areas with good blood flow appear bright, while areas with reduced flow appear darker or have different colors.

A nuclear medicine specialist will analyze your images and write a detailed report for your doctor. This process usually takes 1-2 business days, though urgent results may be available sooner.

Your doctor will explain what the results mean for your specific situation. Normal results show even distribution of the tracer throughout the organ being studied, indicating good blood flow and function.

Abnormal results might show:

• Areas of reduced blood flow (appearing as dark or cold spots)
• Areas of increased activity (appearing as bright or hot spots)
• Uneven distribution of the tracer
• Missing or damaged tissue

Remember that abnormal results don't always mean you have a serious condition. Your doctor will consider your symptoms, medical history, and other test results to make an accurate diagnosis.

What are the risk factors for needing a SPECT scan?

Certain factors increase your likelihood of needing a SPECT scan for diagnosis or monitoring. These risk factors vary depending on the condition being investigated.

For brain-related SPECT scans, risk factors include age over 65, family history of dementia, memory problems, unexplained personality changes, or seizure disorders. Head injuries and certain genetic factors also increase the need for brain imaging.

Heart-related SPECT scans are more common if you have:

• Chest pain or shortness of breath
• High blood pressure or diabetes
• Family history of heart disease
• High cholesterol levels
• History of smoking
• Previous heart attack or heart surgery

Bone scans might be needed if you have unexplained bone pain, cancer history, or suspected bone infections. Your doctor will determine if a SPECT scan is appropriate based on your individual risk factors and symptoms.

What are the possible complications of SPECT scans?

SPECT scans are generally very safe with minimal risks. The amount of radiation exposure is low and considered safe for most people, similar to other routine medical imaging tests.

Serious complications are extremely rare, but it's important to know what to expect. Most people experience no side effects at all from the procedure.

Potential but uncommon complications include:

• Allergic reaction to the radioactive tracer (very rare)
• Bruising or soreness at the injection site
• Anxiety or claustrophobia during the scan
• False positive or negative results requiring additional testing

The radioactive tracer leaves your body naturally through urine and bowel movements within a few days. Drinking plenty of water after your scan helps flush it out more quickly.

Pregnant women should avoid SPECT scans unless absolutely necessary, as radiation can potentially harm the developing baby. Breastfeeding mothers may need to pump and discard milk for 24-48 hours after the scan.

When should I see a doctor about SPECT scan results?

You should follow up with your doctor as soon as your results are available, typically within a few days of your scan. Don't wait for concerning symptoms to develop if you haven't heard back about your results.

Your doctor will schedule a follow-up appointment to discuss your results and any necessary next steps. This conversation is important even if your results are normal, as it helps rule out certain conditions.

Contact your doctor sooner if you experience any unusual symptoms after your scan, such as severe pain at the injection site, persistent nausea, or signs of allergic reaction like rash or difficulty breathing.

You should also reach out if you have questions about your results or need clarification about what they mean for your health. Your healthcare team is there to help you understand your diagnosis and treatment options.