PET CT Scan

Proper preparation helps ensure accurate scan results. Patients are generally advised to:

• Fasting for 4–6 hours before the scan (water is usually allowed).
• Drink plenty of water before your appointment.
• Avoid strenuous exercise for 24 hours before the scan.
• Inform your doctor if you are pregnant, breastfeeding, or taking regular medications.
• Wear comfortable clothing and avoid metal accessories.
• Follow any additional instructions provided by your doctor or imaging centre.

Yes, diabetic patients can safely undergo a PET CT scan. However, their blood sugar levels should be well controlled before the procedure, especially for an FDG PET CT scan. Inform the diagnostic centre about your diabetes and any medications you are taking before your appointment. You may receive specific instructions regarding fasting, insulin, or oral diabetes medications to help ensure accurate imaging results. Always follow your doctor's advice before the scan.

No, a PET CT scan is generally not painful. You may experience slight discomfort when a small amount of radioactive tracer is injected into a vein. After the injection, you will rest for about 45–60 minutes while the tracer is absorbed by your body before the scan begins. During the scan, you will lie still on a scanning table while the machine captures detailed images. The scan itself is non-invasive and usually takes 20–30 minutes.

A PET CT (Positron Emission Tomography–Computed Tomography) scan is an advanced imaging test that combines PET and CT technologies to provide detailed information about both the structure and function of organs and tissues. It is commonly used to detect cancer, monitor treatment response, identify infections and evaluate certain neurological and cardiac conditions. By combining functional and anatomical imaging, a PET CT scan helps doctors make more accurate diagnoses and plan appropriate treatment.

A PET scan indicates:

• Various types of cancers (breast, lung, thyroid cancer etc.)
• Heart-related conditions like coronary artery disease and heart attack
• Brain disorders like tumours, epilepsy, dementia and Alzheimer’s disease

A PET scan measures essential functions within the body, including blood flow, oxygen utilisation, and glucose metabolism. Additionally, it can identify organs and tissues that may not be functioning optimally.

Your healthcare provider recommends this scan when he/she suspects cancer. It is also recommended during treatment and follow-up sessions to:

• understand the spread of cancer
• understand treatment efficiency
• detect cancer recurrence
• understand cancer prognosis

If you have heart issues, take the scan to:

• understand how healthy your heart muscles are
• understand the damage after a heart attack

In neurological health issues, PET scan is recommended to evaluate possible brain abnormalities, such as tumours, seizures and other central nervous system conditions.

Radiotracer is injected into a vein. Fluorodeoxyglucose (FDG) is a commonly used radiotracer. You may also get an IV injection of a contrast dye that helps produce sharper CT images. Cancerous cells absorb FDG. The patient is then imaged on a PET scanner. The scan locates malignant lesions called hotspots and produces images of the affected tissue. PET scan detects cellular-molecular activities within your body to help with accurate diagnosis at an early stage.

Your healthcare provider will give you detailed instructions on how to prepare for the scan. In general, you should:

• Make sure your provider knows your medications and medical conditions/history if any.
• Inform your provider if you’re pregnant or breastfeeding.
• Do not eat for 6 hours before the scan. You can drink water. However, your healthcare provider may change this direction if you have diabetes.
• In case of heart scan, avoid caffeine for 24 hours before the scan.
• Wear comfortable clothes and leave metal accessories, such as jewellery, eyeglasses, dentures and hairpins, at home.

• An IV injection of a radiotracer, commonly fluorodeoxyglucose (FDG)
• Waiting for about an hour to allow the tracer to move through your bloodstream and get absorbed by cells
• Likely an IV injection of a contrast dye to produce sharper CT images
• You’ll lie on an exam table that slides in and out of the PET/CT scanner, which is doughnut- or tunnel-shaped.
• During the scan, usually about 30 minutes, you must remain still. Movement can blur the images.
• You’ll hear buzzing and clicking sounds as the scanner takes images.
• A technologist will review the scans before you leave to ensure the images are in focus.

The complete PET scan procedure takes around 2 hours - 1 hour for your body to absorb the radiotracer + 30 minutes inside the scanner + waiting after the test as the technician checks the scans to verify the photos are clear.

PET scans are safe and rarely cause problems, often in the following situations:

• Pregnancy or breastfeeding stage
• Allergy to tracers or contrast dyes, which is uncommon and mild in nature. The medical team gives you medication to quickly slow and stop the reaction.
• In case of diabetes

You will receive the reports usually in 24-48 hours.