Single Photon Emission Computed Tomography (SPECT)

Single photon emission computed tomography (SPECT) uses radioactive gamma rays that deliver information to high-tech cameras to creates three-dimensional pictures of the brain. The scan captures these images by using two cameras that emit and record gamma-ray activity within the brain.

SPECT shows what areas of the Brain are more active during a seizure or less active between seizures. Two SPECT scans are usually completed, one during a seizure (the ictal period) and one when your child is not seizing (the inter-ictal period). Both Scans are then subtracted from each other and produce a signal super-imposed or coregistered to the MRI (subtraction ictal single-photon emission computerized tomography coregistered to MRI or SISCOM). Unlike MRI scans, which produce images showing the form and structure of the brain, SPECT scans capture images of how the brain functions. The SCAN is often extremely helpful in outlining the region of seizure onset and is completed during your child’s stay in the Epilepsy Monitoring Unit.

A SPECT scan is safe, using only a small amount of radiation, and the patient experiences little to no side. No long-term health risks are associated with the test.


Before a SPECT Scan

An intravenous catheter (IV) will be placed prior to the SPECT scan, delivering a small amount of radioactive tracer into your child’s body. Your child may feel a tiny prick from a needle (which is removed after catheter placement) during placement of the IV catheter and possibly a cold sensation as the tracer is administered. For the next 20 minutes, your child will lay quietly while the body absorbs the radioactive tracer. The catheter often remains for the second SPECT, as descried above, in order to avoid two needle sticks. You may be at your child’s side throughout the entire process..

During a SPECT Scan

A SPECT scan takes place on a horizontal examination table that is surrounded by cameras. Your child will remain laying on the table while the cameras rotate around their head capturing images of the brain. The scan itself is relatively quick with the process lasting 20-40 minutes, but this is patient dependent.

After a SPECT Scan

Your child will require any recovery time after a SPECT scan. The radioactive tracer will naturally flush out of the system although your doctor may encourage your child to drink more liquids to help the process.