Should You Get a PET-CT Scan for Cancer Screening? Insights from Top Chinese Oncologists
- MedBridge NZ
- Jan 9
- 4 min read
By Dr. Zhao Dongbing
Key Takeaways
Not for Healthy People: A PET-CT scan for cancer screening is generally not recommended for healthy individuals due to high radiation exposure and cost.
High Radiation Risk: One scan delivers 10–15 mSv of radiation, which is significantly higher than the international safety standard for annual public exposure.
Accuracy Issues: PET-CT can produce false positives (due to inflammation) and false negatives (missing cancers like stomach or prostate cancer).
Expert Access: Through Medical Tourism China, patients can access leading specialists for personalized screening plans rather than relying on unnecessary high-tech scans.
In the pursuit of health and longevity, many people look for the most advanced technology to screen for potential illnesses. A common question arises in oncology clinics: "Should I get a PET-CT scan for cancer screening, just to be safe?"
Recently, a 40-year-old patient visited my clinic requesting this specific scan. His reasoning was that he had heard it is a routine procedure in countries like Japan and, given his family history of cancer, he wanted the most thorough check-up available.
However, as an oncologist, my advice to him—and to most healthy individuals—is no. While PET-CT is a powerful tool, it is generally not recommended for routine check-ups in healthy populations. Here is why.
What is a PET-CT Scan for Cancer Screening?
PET-CT (Positron Emission Tomography - Computed Tomography) combines two imaging technologies into one examination:
PET: Uses a radioactive drug (tracer) to show metabolic activity in the body. Cancer cells are metabolically active and absorb more of the tracer, "lighting up" on the scan.
CT: Provides a structural X-ray of the body to pinpoint the exact location.
This combination allows doctors to see both the anatomy and the biological function of tissues, detecting tumors as small as 5 millimeters.
When is a PET-CT Scan Actually Useful?
While not for general screening, a PET-CT scan is invaluable in the treatment and staging of confirmed cancer cases. It excels at:
Detecting early recurrence or metastasis (spread) of cancer.
Monitoring how well a treatment is working.
Identifying metabolically active tumors such as lung cancer, lymphoma, esophageal cancer, colorectal cancer, breast cancer, head and neck tumors, and melanoma.
However, its utility changes significantly when applied to healthy people with no symptoms.
Why Healthy People Should Avoid a PET-CT Scan for Cancer Screening
Despite its high-tech appeal, there are three major reasons why medical guidelines worldwide (including in China and the West) do not recommend using a PET-CT scan for cancer screening during routine physicals.
1. High Radiation Exposure
Safety is the primary concern. A single scan exposes a patient to a significant amount of radiation—approximately 10 to 15 mSv (millisieverts).
Context: International standards suggest that the public's average annual radiation exposure should not exceed 1 to 3 mSv.
The Risk: One scan delivers several years' worth of radiation in a single session. For a healthy person, this unnecessary exposure creates a potential health risk rather than preventing one.
2. High Cost
A PET-CT scan for cancer screening is an expensive procedure. In many healthcare systems, the cost ranges significantly and is rarely covered by insurance when used for elective screening without a medical diagnosis. For a routine check-up, the "cost-benefit ratio" is extremely low.
3. The Problem of Accuracy: False Positives and False Negatives
Contrary to popular belief, PET-CT is not a "catch-all" magic scanner.
False Positives (Anxiety): The radioactive tracer accumulates in areas of high metabolism. Unfortunately, inflammation and infection are also metabolically active. A PET-CT scan for cancer screening might light up for a benign infection, looking identical to cancer. This leads to unnecessary panic, further invasive testing, and mental stress for the patient.
False Negatives (Missed Cancers): Some cancers have low metabolic activity and do not show up well on PET-CT. These include prostate cancer, kidney cancer, bladder cancer, primary liver cancer, and certain brain tumors.
Blind Spots: It is notoriously poor at detecting lesions in hollow organs like the stomach and intestines. For example, it can easily miss gastric signet ring cell carcinoma.
The Better Approach: Targeted Screening
Navigating the complexities of cancer screening requires expert guidance rather than just expensive technology. If you are concerned about cancer risk, the best approach is targeted screening based on your age and family history. For example, gastroscopy and colonoscopy remain the gold standards for stomach and bowel cancers—areas where a PET-CT scan often fails.
For international patients seeking access to top-tier medical advice in China, understanding these nuances is vital. This is where a medical concierge provider like MedBridgeNZ becomes essential. While MedBridgeNZ does not provide medical services directly, we specialize in Medical Tourism China, bridging the gap between patients and leading specialists like Dr. Zhao Dongbing to ensure you receive the most appropriate, evidence-based care plans.
Summary
A PET-CT scan for cancer screening is a high-tech tool designed for cancer patients, not for healthy people. It involves high radiation, high costs, and a risk of inaccurate results that can lead to missed diagnoses or false alarms.
Instead of chasing the most expensive machine, consult with a specialist to determine the right screening plan for you. After explaining these facts to my 40-year-old patient, he happily accepted my advice and opted for targeted screenings appropriate for his specific health profile.
About the Author
Dr. Zhao Dongbing
Chief Physician, Professor, and Doctoral Supervisor
Department of Abdominal Surgery
Cancer Hospital of the Chinese Academy of Medical Sciences
Specialty: Diagnosis and treatment of digestive system tumors.
References
Original Video: Why healthy people are not recommended to use PET-CT for cancer screening (为什么健康人并不建议用PET-CT去做癌症筛查). Available at: https://v.douyin.com/XztPtq0Abx4/
