Info
PET-CT (positron emission tomography)
A combined investigation: CT for anatomical structure + PET for metabolic activity. Active cancer cells consume a lot of glucose and are highlighted on the PET images.
What it means
A combined investigation that joins metabolic information (PET) with anatomical detail (CT). It shows which cells are very active (consuming a lot of glucose) and helps detect the spread of the disease, identify small nodules and assess the response to treatment.
In short
A combined investigation: CT for anatomical structure + PET for metabolic activity. Active cancer cells consume a lot of glucose and are highlighted on the PET images.
Where you will see it
Recommended for staging, assessing the response to treatment or detecting a recurrence.
What it does not tell you on its own
Not every active area on a PET scan means cancer — inflammation and infections can look the same. It does not confirm the diagnosis on its own.
Questions for your doctor
- What does the PET-CT show in my case?
- Are there active sites of disease and where?
- Is the disease responding to treatment compared with the previous PET-CT?
- Why a PET and not just a CT?
Related terms
The terms below often appear alongside this one. Each definition is right here, so you do not have to look elsewhere.
- CT (computed tomography)
- An imaging investigation carried out with X-rays that produces cross-sectional images of the body. It helps locate and assess the size of the tumor, check for spread to the lymph nodes and plan treatment.
- MRI (magnetic resonance imaging)
- An imaging investigation that uses a magnetic field and radio waves to produce detailed images of the organs. It does not use ionising radiation. It is useful for assessing the brain, the spinal cord, the prostate and soft tissues.
- Metastasis
- The spread of cancer cells from the site of origin to other organs or tissues. Metastases show that the disease has spread to distant sites and they influence the stage, the prognosis and the type of treatment recommended.
- Lymph node
- A small structure of the lymphatic system, involved in the body's defence. In cancer, the lymph nodes are important for staging, because they can be the route by which the disease begins to spread.
Other terms in “Diagnosis”
Glossary definitions are written for patients by the OncoDots team and go through internal medical review. They explain terms; they do not establish a diagnosis and do not recommend a treatment.