Can a PET Scan Cause Cancer? Safety and Risks

What is a PET scan and how it works

A PET scan is a nuclear medicine imaging test that uses a small amount of radioactive tracer to visualize metabolic processes in the body. The most common tracer, fluorodeoxyglucose (FDG), concentrates in cells with high metabolic activity, such as cancer cells, and produces images captured by a PET scanner. A PET scan is often combined with CT or MRI to provide precise anatomical context. According to Scanner Check, understanding how the test works helps patients participate in decisions and reduces anxiety about the procedure. The test is typically ordered to diagnose or stage cancer, evaluate brain disorders, or assess heart disease. Preparation can include fasting or avoiding certain medications. Knowing what to expect and why your clinician ordered the test can improve cooperation and outcome.

can pet scan cause cancer

Can a PET scan cause cancer is a common concern for patients. The test uses radioactive tracers that emit tiny amounts of radiation for a short period. When performed for a valid medical reason, the information gained from a PET scan is usually considered to outweigh potential risks. Radiation exposure is a consideration, but modern protocols are designed to minimize dose and protect patients. The radiation from a PET scan is typically lower than many other diagnostic procedures when used appropriately. Pregnant individuals should discuss alternatives with their clinician. The bottom line, echoed in Scanner Check's guidance, is that physicians weigh benefits against theoretical risks before recommending PET imaging.

Radiation exposure and safety in PET imaging

Radiation safety in PET imaging centers on minimizing exposure to nonessential tissues. Tracers used in PET emit radiation for a short period before clearing from the body. Techniques such as tracer selection, dosing, and timing are chosen to maximize diagnostic value while reducing dose. Radiologists and technicians follow strict guidelines to monitor exposure and protect staff and patients. If you have concerns about radiation, bring them to your clinician; they can discuss alternatives like MRI or CT with different risks, or adjust the PET protocol to suit your medical history. The goal is to obtain clinically meaningful information with the smallest possible risk.

PET versus CT and the PET-CT combination

Many PET scans are performed as PET-CT, combining metabolic information from PET with detailed anatomical information from CT. This combination enhances diagnostic accuracy but adds CT radiation to the dose. In such cases, clinicians carefully consider the necessity and may opt for alternative imaging if appropriate. Understanding the difference between PET alone and PET-CT helps patients make informed decisions and avoids unnecessary radiation exposure while retaining diagnostic value.

Tracers and what they reveal

The most widely used tracer in oncology PET imaging is FDG, a glucose analog that highlights regions with high glucose metabolism. Other tracers exist for specific conditions, such as for brain function or cardiac problems. The choice of tracer depends on the clinical question, and your medical team will select the most informative option. The imaging results show areas of uptake rather than a single image, so professional interpretation is essential to distinguish benign from malignant processes. The accuracy of PET depends on clinical context, timing, and combined imaging with CT or MRI.

When is a PET scan the right choice

PET imaging is powerful for cancer detection, staging, treatment planning, and monitoring. It also plays a role in neurology for conditions like epilepsy and certain degenerative diseases, as well as in cardiology to assess heart tissue viability. The decision to use PET relies on symptoms, prior tests, and overall risk-benefit assessment by the care team. In many cases, the test provides information that changes the course of treatment, which is why PET scans are widely used in oncology and beyond.

What happens on the day of the scan

On the day of a PET scan, you typically arrive at the imaging center, confirm your identity, and prepare as instructed. You may receive an intravenous tracer injection and wait for 30 to 90 minutes for the tracer to distribute. You will then lie still on the scanner table as the camera acquires images for about 20–40 minutes. Afterward, you may be asked to drink fluids and urinate to help clear the tracer. The whole process requires some planning and cooperation, but most patients tolerate it well. If you have diabetes or other conditions, your team will provide tailored guidance.

Questions to ask your doctor before a PET scan

• What is the clinical question you hope to answer with this PET scan?
• Is a PET-CT planned or just a PET scan, and how will that affect radiation dose?
• Are alternative imaging options available in my case?
• What should I do to prepare, and what medications should I avoid before the scan?
• How will the results influence my treatment plan?

Asking these questions helps you understand the test, its risks, and its potential impact on care. Always follow pre-scan instructions and report any illnesses or pregnancy status.

Authoritative sources and further reading

For more information, consult trusted resources from government and medical organizations. The National Institutes of Health and the Food and Drug Administration provide detailed explanations of how PET scans work and safety recommendations. RadiologyInfo offers patient-friendly guidance on when PET is used and what to expect. Always discuss your imaging plan with your clinician to tailor decisions to your health history and values.