PET Scan in Cancer Diagnosis at the National Cancer Centre Singapore

A Positron Emission Tomography (PET) scan is an advanced imaging technique that shows how organs and tissues are functioning. This powerful diagnostic tool is used across multiple medical specialties including oncology, cardiology, neurology, and for detecting infection and inflammation.

PET scans are used to detect cancer, assess treatment response, and guide therapy planning. As PET is extremely sensitive and able to detect abnormalities even in the absence of structural changes , doctors can identify disease activity with precision and obtain a clearer understanding of each patient’s condition. This helps in choosing the best treatment option for patients.

What Is a PET Scan

A PET scan uses a small amount of radioactive tracer to measure metabolic activity within the body. Areas of increased tracer uptake may indicate cancer, inflammation, or other abnormalities.

When combined with Computed Tomography (PET/CT) or Magnetic Resonance Imaging (PET/MRI), the scan provides both functional and anatomical information for more accurate assessment.

How PET Scans Support Cancer Diagnosis and Treatment

PET imaging complements other imaging methods by providing functional information that helps doctors understand how cancer behaves in the body.

• Early detection: PET scans can reveal abnormal metabolic activity before physical changes are visible on other scans. 
• Accurate staging: By identifying the spread of disease, PET scans help determine the most appropriate treatment strategy. 
• Treatment planning: PET/CT and PET/MRI results guide decisions on surgery, radiotherapy, or systemic therapy. 
• Monitoring response: Serial PET scans help assess how well a treatment is working and detect recurrence early. 
• Comprehensive review: Results are interpreted by nuclear medicine physicians and discussed at multidisciplinary tumour boards to ensure coordinated care.

Patient Preparation and Safety

NCCS patients who require PET/CT scans will be referred to SGH’s Department of Nuclear Medicine and Molecular Imaging for the procedure.

The PET scan is a safe procedure, with only a small amount of radioactive tracer used. 

• Inform your care team if you are pregnant, breastfeeding, diabetic, or taking medication that may affect the scan. 
• You may be asked to fast for several hours before the test. 
• Avoid strenuous physical activity 24–48 hours prior to your appointment. 
• Wear comfortable clothing without metal fasteners or accessories.
•  The care team will provide specific preparation guidance to help ensure accurate results.

What to Expect

1. Referral and Scheduling

Your care team at NCCS will arrange the PET scan as part of your diagnostic or treatment plan.

2. Before the Scan

You will receive detailed preparation instructions, including fasting requirements and medication review.

3. Tracer Injection and Uptake Period

A small amount of tracer is injected into a vein, followed by a resting period of about 60–90 minutes while it circulates in the body.

4. During the Scan

You will lie on a scanning bed that moves slowly through the scanner. The process takes around 30–40 minutes. You must remain still to ensure image clarity.

5. After the Scan

Most patients can resume normal activities immediately. Drinking plenty of fluids helps clear the tracer from the body. Your results will be sent to your care team at NCCS. Your doctor will review the results and discuss with you the next steps or additional investigations if required.

Guidance and Support

PET scanning is one of several advanced imaging tools used to support your cancer diagnosis, treatment planning, and ongoing care at NCCS. Your care team will explain the procedure, preparation steps, and how the findings contribute to your treatment plan.

For more information about PET scans and diagnostic imaging services, please visit www.nccs.com.sg or speak with your NCCS care team.