F18 FDG Brain Scan

What is F18 FDG Brain Scan?

A Positron Emission Tomography (PET) scan is a diagnostic imaging procedure used to determine how organs and tissues inside the body are functioning. It allows the detection of certain diseases even before patients display symptoms, allowing for disease development to be determined much more accurately than with other diagnostic imaging techniques.

The F18 FDG Brain Scan is a PET scan that examines the structure and functionality of the brain and its tissues. It can detect the onset of neurological disorders such as dementia (which includes Alzheimer’s disease), and other neurodegenerative disorders.

What happens before a F18 FDG Brain Scan?

  • Fast for at least 4-6 hours before the scan
  • Refrain from taking caffeine, alcohol and smoking 24 hours before the scan
  • Stay hydrated with plain water
  • Follow a high protein and low carbohydrate diet 24 hours prior to the scan for normal distribution of the radioactive glucose (F18-FDG) in your body
  • Stop taking sedatives and anesthetic drugs if your doctor advises so
  • Intravenous fluids containing dextrose or parenteral feedings should be withheld for four to six hours
  • Inform your physician of any possible allergies to contrast material
  • Inform your physician if you have a renal disease and is on Metformin (medication)
  • If you have a fear of enclosed spaces, inform your physician. Medicine or sedatives to help you relax during the procedure may be prescribed.

What happens during a F18 FDG Brain Scan?

  • The scan will take about 2-3 hours to complete. As the radiotracer used in the scan decays very quickly through a natural process, it is important that you arrive punctually for the scan to be conducted timely.
  • When you arrive at the Nuclear Medicine Suite, you will be asked about your medical history with your blood glucose level checked before receiving a small amount of radiotracer.
  • You will be expected to stay in the procedure room for 30 before the nuclear medicine technologist conducts the scan, which will take about 10 minutes.

What happens after a F18 FDG Brain Scan?

  • After the scan, you should experience little to no side effects.
  • As the PET radiotracer decays quickly, it will also be excreted quickly through your urine.
  • To expedite the process, you are encouraged to drink plenty of fluids. For precaution, avoid close contact with children and pregnant ladies for at least eight hours.


Should you feel unwell after the procedure, contact your doctor immediately or call our 24-Hour Medical Urgency Clinic at (65) 6705 2999.


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