SPECT scan

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SPECT scan

SPECT scan — Learn what happens during SPECT scans, including brain SPECT and cardiac SPECT.

A single-photon emission computerized tomography (SPECT) procedure lets your doctor analyze the function of your internal organs. A SPECT scan is a type of nuclear imaging test, which means it uses a radioactive substance and a special camera to create pictures of your organs. While imaging tests such as X-rays can show what the structures inside your body look like, a SPECT scan produces three-dimensional images that show how your organs work — for instance, how blood flows to your heart or what areas of your brain are more active or less active.

How do you prepare for a SPECT scan?

How you prepare for a SPECT scan depends on your particular situation. In many cases, no restrictions are placed on what you can eat or drink before the procedure. Other times you may be allowed only water after midnight before the procedure. Before a SPECT scan of your heart, you may be asked to avoid caffeine or to stop taking certain medications. Ask your health care team whether you need to make any special preparations before your SPECT scan.

What can you expect during a SPECT scan?

You may feel some discomfort during your injection or infusion of radioactive tracer when the needle is inserted in your vein. Some people are allergic to the chemicals in the tracer, so tell your doctor about any allergies you have.

The SPECT scan won't hurt. But you may feel uncomfortable lying still for an extended period. You may be offered a sedative to relax you.


For most people, SPECT scans are safe. If you receive an injection or infusion of radioactive tracer, you may experience bleeding, pain or swelling where the needle was inserted in your arm. Rare allergic reactions to the radioactive tracer are possible, so tell your doctor about any allergies you have.

SPECT scans aren't safe for women who are pregnant or breast-feeding because the radioactive tracer may be passed to the developing fetus or the baby. Women of childbearing age may be required to take a pregnancy test before a SPECT procedure.

Most of the radioactive tracer leaves your body through your urine within a few hours after your SPECT scan. Your doctor may instruct you to drink more fluids, such as juice or water, after your SPECT scan to help flush the tracer from your body. Your body breaks down the remaining tracer over the next day or two.

Your health care team uses the lowest amount of radiation possible in order to perform the scan. How much radiation you're exposed to depends on many factors, such as your particular SPECT procedure and your own body. In general, a SPECT scan exposes you to radiation levels similar to those you might encounter naturally in the environment over the course of a year. Talk to your doctor if you're concerned about your exposure to radiation during a SPECT scan.

Last Updated: 03/07/2007
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