A PET (Positron Emission Tomography) scan involves injecting a radioactive tracer, usually a form of glucose, and then using a special scanner to detect areas of high metabolic activity in the body. Here's a breakdown of the typical procedure:
1. Preparation:
- Fasting: You may be asked to fast for several hours before the scan, typically avoiding food and sugary drinks. This helps the tracer distribute properly in your body.
- Hydration: Drinking water is usually encouraged to help with image clarity and tracer elimination.
- Medical History: You'll be asked about your medical history, including any allergies, medications, and previous medical conditions, particularly diabetes.
- Blood Sugar Check: For FDG PET scans, your blood sugar levels might be checked before the injection, as high blood sugar can affect the accuracy of the scan.
- Clothing and Jewelry: You'll likely need to change into a hospital gown and remove any jewelry or metallic objects that could interfere with the scan.
2. Tracer Injection:
- Tracer Administration: A small amount of a radioactive tracer is injected into a vein, typically in your arm. The most common tracer is fluorodeoxyglucose (FDG), which is a radioactive form of glucose (sugar).
- Uptake Period: After the injection, there is an uptake period, usually around 60 minutes, where you will be asked to relax quietly. This allows the tracer to distribute throughout your body and be absorbed by tissues.
3. The Scan:
- Positioning: You will lie on a narrow table that slides into the PET scanner.
- Scanning Process: The PET scanner detects the radioactive emissions from the tracer in your body. It does not feel like anything.
- Duration: The scanning process itself usually takes between 30 minutes to an hour, depending on the area of the body being scanned and the specific protocol.
4. After the Scan:
- Hydration and Elimination: You'll be encouraged to drink plenty of fluids to help flush the radioactive tracer from your system.
- Normal Activities: You can usually resume your normal activities immediately after the scan. However, it is advisable to avoid close contact with pregnant women and infants for a short period (usually a few hours) as a precaution.
- Results: A radiologist will analyze the PET scan images and send a report to your doctor. Your doctor will then discuss the results with you and determine the next steps.
Important Considerations:
- Radiation Exposure: PET scans involve a small amount of radiation exposure, but the benefits of the scan usually outweigh the risks. The amount of radiation is generally considered low and dissipates quickly.
- Pregnancy and Breastfeeding: It's crucial to inform your doctor if you are pregnant or breastfeeding, as the radioactive tracer could potentially harm the fetus or infant.
- Claustrophobia: If you are claustrophobic, inform the medical staff before the scan. They may be able to offer medication or other strategies to help you relax.
