A PET scan is a medical imaging test that helps detect cancer and other diseases by showing how cells in the body are functioning.
It involves injecting a small amount of a radioactive sugar compound called FDG (Fluorodeoxyglucose), which contains a tracer labeled with a radioactive element (F-18).
Because cancer cells consume more sugar than normal cells, FDG tends to accumulate in areas where cancer may be present. This buildup can then be visualized on the PET scan.
PET-CT
What is a PET Scan?
What Makes PET/CT Special?
Traditional imaging methods like CT and MRI focus on the shape and size of organs.
In contrast, a PET scan shows how tissues are working at the cellular level based on sugar metabolism.
At our hospital, we use a Philips PET/CT scanner, which combines two powerful technologies:
- PET scan: shows metabolic activity of cells
- CT scan: shows detailed images of organs and structures
By combining these, we can more precisely locate abnormal areas and assess their size and severity.
How PET/CT Helps
PET/CT is especially helpful in:
- Cancer detection and screening
- Determining if a tumor is cancerous (malignant)
- Staging cancer (checking for lymph node or distant spread)
- Detecting recurrence of cancer
- Evaluating the effectiveness of treatment
- Finding the original tumor site in cases of unknown primary cancer
Cancers Where PET Is Particularly Effective
- Head and neck cancer
- Lung cancer
- Breast cancer
- Esophageal cancer
- Pancreatic cancer
- Colon cancer
- Ovarian cancer
- Uterine (endometrial) cancer
- Malignant lymphoma
- Melanoma
- Metastatic liver cancer
Cancers Less Visible on PET Scans
- Stomach cancer
- Bladder cancer
- Prostate cancer
- Cervical cancer
- Primary liver cancer
- Early-stage gastrointestinal cancers
- Leukemia
Limitations of PET Scans
PET scans may not detect small cancers or certain types of cancer.
Also, FDG can accumulate in areas of inflammation or infection, not just cancer.
While PET is a powerful diagnostic tool, it’s not perfect and should be interpreted together with other tests.
Your PET/CT Scan Appointment
What to Expect
1.Check-in
Please come fasting—no food for at least 5 hours before your appointment.
Water or tea is allowed (no sugar or sweetened drinks).
2.Pre-scan interview
We will ask you questions and explain the procedure.
3.Injection
We will check your blood sugar and inject FDG into a vein.
4.Resting Period
You will rest quietly for about 1 hour to allow the FDG to spread throughout your body.
5.Scan
We will perform the PET/CT scan, which takes about 20–30 minutes.
6.Rest and Review
After the scan, please rest for about 30 minutes while we confirm if additional images are needed.
7.Completion
The entire process takes approximately 3 hours.
Radiation Exposure from PET/CT
A single PET scan exposes you to about 2.2 mSv of radiation—slightly less than the average yearly exposure to natural background radiation.
When combined with the CT scan (3–10 mSv), the total dose is still considered very low and safe, with minimal health risk.
Frequently Asked Questions
What should I do before the scan?
Please fast for at least 5 hours. You may drink water or unsweetened tea, but avoid sugary drinks.
Refrain from strenuous exercise and excessive talking or singing before the test.
How long does the test take?
The scan itself takes about 20–30 minutes, but including preparation and resting time, the full appointment lasts around 3 hours.
Is the scan painful?
Other than a small pinch when the injection is given, the scan is painless.
I have diabetes. Can I still have a PET scan?
Yes, diabetic patients can have PET scans. However, if your blood sugar is over 200 mg/dL, the scan may not work properly.
Please manage your blood sugar well before the test day.
If you have any other questions or concerns, please don’t hesitate to contact our staff. We’re here to support you through your health journey.