What are the steps to order a Positron Emission Tomography/Computed Tomography (PET/CT) scan?

From the Guidelines

To order a PET/CT scan, first determine if the scan is clinically indicated for your patient based on their condition, such as cancer staging, neurological disorders, or cardiac issues, and then follow the most recent guidelines for patient preparation and scanning protocols, as outlined in the 2024 EANM guidelines 1. When ordering a PET/CT scan, several steps must be taken to ensure the procedure is conducted safely and effectively.

• Determine the clinical indication for the scan, such as cancer staging, neurological disorders, or cardiac issues.
• Verify insurance coverage and obtain prior authorization, as these scans are expensive and often require approval.
• Complete a detailed requisition form including the patient's clinical history, diagnosis codes (ICD-10), specific area to be scanned, and any relevant previous imaging results.
• Schedule the scan with a radiology department or imaging center that has PET/CT capabilities.
• Provide patient preparation instructions, which typically include:
  • Fasting for at least 4 hours before the scan, as recommended by the 2024 EANM guidelines 1 and the 2015 EANM procedure guidelines for tumour imaging: version 2.0 1.
  • Avoiding strenuous exercise for at least 6 hours before the scan, and preferably for 24 hours, as stated in the 2015 EANM procedure guidelines for tumour imaging: version 2.0 1.
  • Maintaining proper hydration, with adequate prehydration, such as consumption of 1 liter of water 2 hours prior to [18F]FDG injection, as recommended in the 2024 EANM guidelines 1 and the 2015 EANM procedure guidelines for tumour imaging: version 2.0 1.
• Inform patients they will receive an injection of a radioactive tracer (usually 18F-FDG) approximately one hour before the scan.
• The entire procedure takes about 2-3 hours, though the scan itself lasts only 20-40 minutes, as stated in the example answer.
• After the scan, patients can usually resume normal activities, though they should avoid close contact with pregnant women and young children for several hours due to the radioactive tracer. It is essential to follow the most recent guidelines for patient preparation and scanning protocols, as outlined in the 2024 EANM guidelines 1, to ensure the best possible outcomes for patients undergoing PET/CT scans.

From the FDA Drug Label

The recommended dose of Fludeoxyglucose F 18 Injection for an adult (70 kg) is 185-370 MBq (5-10 mCi), as an intravenous injection for studies of malignancy, cardiology, and epilepsy. Patient Preparation: Blood glucose levels should be stabilized before Fludeoxyglucose F 18 Injection is administered. Imaging: Optimally, it is recommended that positron emission tomography (PET) imaging be initiated within 40 minutes of administration of Fludeoxyglucose F 18 Injection.

To order a Positron Emission Tomography/Computed Tomography (PET/CT) scan, the following steps should be taken:

• Ensure the patient has fasted for 4-6 hours before the scan, or has received a glucose load (e.g., 50-75 grams, 1-2 hours before administration of Fludeoxyglucose F 18 Injection) for cardiac imaging.
• Stabilize the patient's blood glucose levels before administering Fludeoxyglucose F 18 Injection.
• Administer the recommended dose of Fludeoxyglucose F 18 Injection (185-370 MBq or 5-10 mCi) via intravenous injection.
• Initiate PET imaging within 40 minutes of administration of Fludeoxyglucose F 18 Injection 2.

From the Research

Steps to Order a PET/CT Scan

To order a Positron Emission Tomography/Computed Tomography (PET/CT) scan, the following steps can be taken:

• Review the patient's medical history and current condition to determine if a PET/CT scan is necessary 3, 4
• Ensure the patient is properly prepared for the scan, including restrictions on diet and activity, and management of blood glucose levels in diabetic patients 3, 5, 6
• Check the patient's blood glucose levels to ensure they are within the acceptable range for the scan, as high blood glucose levels can affect the quality of the images 5, 6
• Schedule the PET/CT scan at a time when the patient's blood glucose levels are likely to be stable 5, 6
• Consider the patient's medication and environmental conditions that may affect the scan results 3

Patient Preparation

Patient preparation is crucial for obtaining good-quality images from a PET/CT scan. This includes:

• Fasting for a certain period before the scan 3, 6
• Avoiding strenuous activity before the scan 3
• Managing blood glucose levels in diabetic patients 3, 5, 6
• Avoiding certain medications that may affect the scan results 3

Scheduling the Scan

Scheduling the PET/CT scan can be done efficiently using simple preparation instructions, even in patients with diabetes or hyperglycemia 5, 6. The scan can be scheduled at a time when the patient's blood glucose levels are likely to be stable, and the patient has been properly prepared for the scan.

PET/CT Scan Protocol

The PET/CT scan protocol may vary depending on the patient's condition and the purpose of the scan. However, the following general steps are typically involved:

• The patient is injected with a tracer, such as 18F-FDG 3, 7, 4
• The patient undergoes a CT scan to provide anatomical information 7, 4
• The patient undergoes a PET scan to provide functional information 7, 4
• The PET and CT images are combined to provide a comprehensive view of the patient's condition 7, 4