# What is a PET-CT scan and what is it used for in cancer?

Source: https://oncologyistanbul.com/answers/what-is-a-pet-ct-scan
Last updated: 2026-07-12

According to the National Cancer Institute (NCI), a PET-CT scan is a procedure that combines the pictures from a positron emission tomography (PET) scan and a computed tomography (CT) scan. NCI notes the PET and CT scans are done at the same time with the same machine, and the combined scans give more detailed pictures of areas inside the body than either scan gives by itself. In a PET scan, a small amount of radioactive glucose (sugar) is injected into a vein; because cancer cells often take up more glucose than normal cells, the pictures can be used to find cancer cells in the body. NCI states a PET-CT scan may be used to help diagnose disease, such as cancer, plan treatment, or find out how well treatment is working. This is general information, not personal medical advice.

## Verify at
- [NCI Dictionary — PET-CT scan](https://www.cancer.gov/publications/dictionaries/cancer-terms/def/pet-ct-scan) — National Cancer Institute (NCI) (checked 2026-07-12)
- [NCI Dictionary — PET scan](https://www.cancer.gov/publications/dictionaries/cancer-terms/def/pet-scan) — National Cancer Institute (NCI) (checked 2026-07-12)

Related: [PET-CT, defined in the glossary](https://oncologyistanbul.com/glossary/pet-ct)