Back
Logo ComoMePreparoHowDoIPrepare.com

FDG PET-CT

General instructions for FDG PET-CT

Imaging test that uses a small amount of radioactive glucose to detect diseases and evaluate cellular metabolism.

  • Fasting: It is strictly necessary to fast from solid food and liquids for at least 6 hours before the test. However, drinking plenty of plain water is allowed and highly recommended to stay well hydrated.
  • Medication: If you have diabetes, taking insulin or oral diabetes medication will require very precise instructions, as blood sugar levels directly affect the result; your blood glucose must be well controlled on the day of the test (usually below 150-200 mg/dL, according to your centre's instructions), and if it is too high, the test may have to be postponed. In any case, any decision to stop, continue or adjust your usual medication must always be discussed with your doctor.
  • Clothing and Accessories: We recommend wearing loose, comfortable and preferably warm clothing, as PET-CT rooms are usually kept cold. There is a strict restriction on metal: do not wear garments with zips, underwiring or metal fasteners, and you will have to remove all jewellery, piercings, hairpins and watches before the scan.
  • Specific Requirements: For the 24 hours beforehand, you must follow a strict diet without carbohydrates or sugars (avoiding pasta, rice, bread, potatoes, fruit, alcohol and sweets) and avoid intense physical exercise. On the day of the test, after the radiopharmaceutical is injected, you will have to rest in complete silence and without moving for about 45 to 60 minutes before going into the scanner. You do not need to come with a companion unless you suffer from severe claustrophobia and need some form of sedation. After the test, you should drink plenty of water to eliminate the tracer and keep a sensible distance from pregnant women and young children for the following 6 to 8 hours.
  • Discomfort or pain after the test: The procedure itself is completely painless. You will only feel a slight prick when the healthcare professional inserts a line into a vein to inject the radiopharmaceutical (which does not sting or feel warm). The main discomfort is usually having to lie on your back completely still inside the scanner (a wide, open ring, not a closed tube) for about 30 to 45 minutes.
  • Please note: If you are breastfeeding, tell the staff before the test.