 Single Photon Emission Computed Tomography (SPECT)
Single Photon Emission Computed Tomography is a functional imaging technique which creates 3-dimensional images of the brain on computer, allowing physicians to visualize blood flow through different areas of the brain.
Individuals with epilepsy often have changes in blood flow to specific areas of the brain when a seizure begins. The SPECT measures blood flow between seizures and during seizures. The scans are then compared to identify the changes in blood flow in specific areas of the brain, thus identifying where seizures originate.
This test provides information about how well the various regions of the brain are functioning by measuring relative cerebral blood flow. This information helps your physician to more accurately diagnose the type of seizure, locate the site where a seizure originates, and evaluate a potential candidate for surgery.
The radiation exposure from a brain scan is small. It is in the range of 1 to 3 times your annual exposure to natural background radiation.
Before a SPECT Exam
- No special diet or medication is required.
- Dress in comfortable clothing.
- Metal objects including jewellery, keys, coins, pens, etc., must be removed before the examination because they can cause defects in the scan.
During a SPECT Exam
- A technician will ask you questions about your past medical history (head injury, seizures, stroke).
- You will lie on your back and a small amount of radioactive substance will be injected into a vein in your arm or hand. This radioactive agent will localize in an area of the brain and will be imaged with a camera.
- Adverse reactions to this substance are very rare, and even then, only a mild skin reaction such as a rash.
- You will be asked to continue lying down for another 10 to 20 minutes.
- A large camera will then be moved near your head; it will take several pictures which will show how well blood flows through various areas of your brain. The camera will remain close to your head throughout the exam. The camera will rotate once around your head and lightly brush your shoulders. It will not touch any other part of your body.
- Only the slight noise of the rotation of the camera and the cooling fans in the equipment will be heard. There are no loud noises during the examination.
- You will be instructed to remain still and breath normally. Any movement will blur the images. The scan may have to be repeated if there is movement of the head.
- You will be able to communicate with the technologist throughout the procedure.
- Preparation for the examination takes 30 minutes; the imaging takes another 30 minutes.
After a SPECT Exam
- When scanning is complete, you may go home and resume your normal activities.
- The images will be given to a radiologist or physician for interpretation. A report will then be sent to your doctor.
PersonnelNuclear Medicine Technologist (NMT)- works under the supervision of physicians to perform the SPECT exam;
- prepares, measures, and gives radioactive tracer to patients by injection or orally.
Doctor
Payment
A SPECT exam is covered by the Ontario Health Insurance Plan (OHIP).
Important Considerations
- Pregnant women should not undergo a SPECT scan because of the radioactive isotopes used.
- Be sure to inform your doctor if you are, or think you are pregnant, before proceeding with a nuclear medicine scan.
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