Description
Why It’s Done
A Whole Body PET Scan With Comparison is commonly ordered when:
• Monitoring response to cancer treatment
• Checking for cancer recurrence
• Tracking progression or regression of known disease
• Evaluating the effectiveness of chemotherapy, radiotherapy, or immunotherapy
• Following up on previously detected abnormalities
By comparing with earlier scans, doctors can:
• Identify new areas of concern
• Evaluate the effectiveness of therapy
• Guide further treatment decisions
Preparation
To obtain the most accurate results, please follow these instructions:
1. Fasting:
• Do not eat or drink anything except plain water for 4–6 hours before the scan.
• Avoid sugary or high-carb meals the day before the test.
2. Hydration:
• Drink plenty of water unless instructed otherwise. This helps distribute and flush out the tracer.
3. Blood Sugar Control:
• Blood glucose should ideally be below 150 mg/dL at the time of the scan.
• Diabetic patients should coordinate with their doctor about insulin or medication timing.
4. Medications:
• Continue regular medications unless told otherwise.
• Bring a list of all medications you are currently taking.
5. Avoid Certain Substances:
• No caffeine, alcohol, smoking, or vigorous exercise for 12–24 hours before the scan.
6. Previous Imaging:
• Bring or ensure availability of previous PET/CT or CT scans for comparison (if performed at a different facility).
• The comparison is crucial for assessing changes in disease status.
7. Clothing:
• Wear loose, metal-free clothing (no zippers, snaps, underwire, or jewelry).
• You may be asked to change into a hospital gown.
8. Inform Your Provider If:
• You are pregnant, breastfeeding, or planning to become pregnant
• You have kidney problems (especially if a contrast-enhanced scan is expected)
• You’ve had recent surgeries, infections, or vaccinations


