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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.

  • Definition: An 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 maintain good hydration.
  • Medication: If you have diabetes, taking insulin or oral antidiabetics 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 (generally below 150-200 mg/dL, as indicated by your center); if it is too high, the test may need to be postponed. In any case, the decision to stop, maintain, or adjust your usual medication must always be discussed with your doctor.
  • Clothing and Accessories: We recommend coming in loose, comfortable, and preferably warm clothing, as PET-CT rooms are usually kept at low temperatures. There is a strict restriction regarding metals: do not use garments with zippers, wires, or metal clasps, and you must remove all jewelry, piercings, hairpins, and watches before the scanner.
  • Specific Requirements: During the 24 hours prior, you must follow a strict diet without carbohydrates or sugars (avoiding pasta, rice, bread, potatoes, fruits, alcohol, and sweets) and abstain from performing intense physical exercise. On the day of the test, after injecting the contrast, you must rest in absolute silence and without moving for about 45 to 60 minutes before passing to the machine. It is not necessary to come accompanied, unless you suffer from severe claustrophobia and require some type of sedation. After the test, you should drink plenty of water to eliminate the drug and maintain a prudent distance from pregnant women and small children during the following 6 to 8 hours.
  • Expected discomfort or pain from the test: The procedure itself is completely painless. You will only feel a slight initial prick when the healthcare professional places a line in the vein to inject the radiopharmaceutical (which does not sting or produce heat). The biggest discomfort is usually the need to remain lying on your back and completely still inside the scanner (which is a wide and open ring, not a closed tube) for about 30 to 45 minutes.